A Review of Contemporary Ideomotor Theory

A Review of Contemporary Ideomotor Theory

Yun Kyoung Shin, Robert W. Proctor, and E. J. CapaldiPurdue University

A framework for action planning, called ideomotor theory, suggests that actions are represented by theirperceivable effects. Thus, any activation of the effect image, either endogenously or exogenously, willtrigger the corresponding action. We review contemporary studies relating to ideomotor theory in whichresearchers have investigated various manipulations of action effects and how those effects acquirediscriminative control over the actions. Evidence indicates that the knowledge about the relation betweenresponse and effect is still a critical component even when other factors, such as stimulus–response orresponse–response relations, are controlled. When consistent tone effects are provided after responses aremade, performance in serial-reaction tasks is better than when the effects are random. Methodology inwhich acquisition and test stages are used with choice–reaction tasks shows that an action is automat-ically associated with its effect bilaterally and that anticipation of the effect facilitates action. Ideomotorphenomena include stimulus–response compatibility, in which the perceptual feature of the stimulusactivates its corresponding action code when the stimulus itself resembles the effect codes. For this reason,other stimulus-driven action facilitation such as ideomotor action and imitation are treated as ideomotorphenomena and are reviewed. Ideomotor theory also implies that ongoing action affects perception ofconcurrent events, a topic which we review briefly. Issues concerning ideomotor theory are identified andevaluated. We categorize the range of ideomotor explanations into several groups by whether intermediatesteps are assumed to complete sensorimotor transformation or not and by whether a general theoreticalframework or a more restricted one is provided by the account.

Keywords: ideomotor theory, motor control, action planning, common coding, response– effectassociation

An approach to perception–action relations called ideomotortheory originated in the 19th century along two roots (Stock &Stock, 2004): those of the German philosophers Herbart (1816,1825), Lotze (1852), and Harless (1861) and those of the Britishphysiologists Laycock (1845) and Carpenter (1852). Various ver-sions of ideomotor theory have been promulgated, but the ideabehind them all is that internal images of actions and the actionsthemselves are tightly linked or that perceptual events tend togenerate actions for which the feedback is similar. James (1890/1950) emphasized ideomotor theory and brought it to the attentionof many psychologists. With the advent of behaviorism, ideomotortheory fell into disfavor due to challenges posed by Thorndike(1913) and others. The first modern statement of ideomotor theorywas that of Greenwald (1970), who published studies on what hecalled the ideomotor principle. Also in the early 1970s, someanimal learning researchers began to incorporate the concept ofaction effect in their theories (e.g., Bolles, 1972). However, wide-spread interest in ideomotor theory did not occur until later,

starting with a chapter by Prinz (1987). Since then, there has beenincreasing effort devoted to developing ideomotor theory andconducting experiments related to the principle.

Stock and Stock (2004) reviewed the history of ideomotortheory up to the middle of the 20th century. The present article isintended as a complement to their article; in it, we review andevaluate contemporary work on ideomotor theory from that time tothe present. After describing use of the term ideomotor, we brieflydiscuss the early views of ideomotor theory. In the remainder ofthe article, we review contemporary research.

Use of the Term Ideomotor

As of Week 1 of February 2010, PsycINFO listed 134 entrieswith ideomotor/ideo-motor in the title and 517 results with it askeyword. About 60% of those entries are related to the study ofideomotor apraxia, a neurological disorder characterized by aninability to translate an idea into voluntary movement (Rothi &Ochipa, 1991). In other entries, the term ideomotor/ideo-motor isused in various contexts, with the concept loosely defined. Ideo-motor action narrowly indicates movements that arise in individ-uals while they observe actions of others (e.g., Knuf, Aschersle-ben, & Prinz, 2001) or action control guided by an anticipatoryrepresentation of the action’s sensory feedback (e.g., Elsner &Hommel, 2001). Several investigators have also studied ideomotor(IM)-compatible tasks for which the response feedback resemblesthe stimulus (e.g., Greenwald & Shulman, 1973). The followingare examples of use of the term ideomotor:

This article was published Online First September 6, 2010.Yun Kyoung Shin, Robert W. Proctor, and E. J. Capaldi, Department of

Psychological Sciences, Purdue University.Robert W. Proctor’s work on the article was supported in part by Army

Research Office Multidisciplinary University Research Initiative GrantW911NF-05-1-0153.

Correspondence concerning this article should be addressed to YunKyoung Shin, Department of Psychological Sciences, Purdue University,West Lafayette, IN 47907-1364. E-mail: [email protected]

Psychological Bulletin © 2010 American Psychological Association2010, Vol. 136, No. 6, 943–974 0033-2909/10/$12.00 DOI: 10.1037/a0020541

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• “The term ideomotor action denotes body movements thattend to arise in observers watching other people perform certainactions” (Knuf et al., 2001, p. 779).

• “The term ideo-motor action has been used to refer to move-ments that are performed in accordance with movements that areperceived—i.e., to situations where action is (seems to be) imme-diately guided by perception” (Prinz, 1987, p. 47).

• “In terms of IM [ideomotor] theory, the response code isdirectly activated by signals that closely resemble sensory feed-back from the response. A relationship between stimulus andresponse of IM compatibility is defined, then, as one in which thestimulus resembles sensory feedback from the response” (Green-wald & Shulman, 1973, p. 70).

• “The feedback of the button-pressing response does not totallyresemble the vibration stimulation and the ideomotor compatibilityis relatively low” (ten Hoopen, Akerboom, & Raaymakers, 1982,p. 156).

Ideomotor comes from the Greek word idea, meaning form, andthe Latin word motare, meaning to move about, and is defined byMerriam-Webster’s Online Dictionary as “not reflex but motivatedby an idea” (“Ideomotor,” n.d.). Most of the ideomotor referentsindicate phenomena of induced action either endogenously orexogenously. Historically, ideomotor action has referred to sym-pathetic action, which is induced movement evoked by a dynamicvisual scene (Knuf et al., 2001; Prinz, 1987). Though research hasfocused mainly on the influence of perceivable environmentalchange on action, as reflected by use of the more popular termideomotor action rather than the term ideomotor perception, theideomotor approach does not deny the opposite direction of influ-ence on perception while a certain action is being performed.

Historical Background of Ideomotor Action

The term ideomotor action was first coined by Carpenter (1852),who viewed ideomotor action as a “reflex action of the cere-brum . . . that manifests itself not only in Psychical change, butalso in Muscular movements: and these may . . . proceed . . . fromsimple Ideas, without any excitement of Feeling, in which casethey may be designated ideo-motor” (1874, p. 105). Carpenter isknown for invoking ideomotor action to explain paranormal phe-nomena such as table turning in seances, “magic” movement of apendulum held by a string, and movement of a divining rod usedfor dowsing. These reflex actions were considered by him to bemost evident for situations in which “the current of thought andfeeling flows on under the sole guidance of Suggestion, andwithout any interference from the Will” (1874, p. 105). Carpenteralso considered ideomotor action to be involved in many behav-iors, stating, “We may range under the same category all thoseactions performed by us in our ordinary course of life, which arerather the automatic expressions of the ideas that may be dominantin our minds at the time, than prompted by distinct volitionalefforts” (1874, p. 280). According to Carpenter, “In a certain stateof mental concentration, the expectation of a result is sufficient todetermine—without any voluntary effort, and even in opposition tothe Will (for this may be honestly exerted in the attempt to keepthe hand perfectly unmoved)—the Muscular movements by whichit is produced” (1874, p. 287).

Carpenter’s views on ideomotor action were based on those ofLaycock (1845), who observed that hydrophobic patients (i.e.,

persons with rabies) reacted physically not only to water itself butalso to the idea of water provided through suggestion. From theseobservations, Laycock concluded that mental images were suffi-cient to initiate actions reflexively. Laycock (1860) treated volun-tary motoric acts in a similar manner, saying, “The intent as to thefuture . . . arises in the consciousness before the state ‘I will’passes into act. This includes two things—a perception of the end,and a desire to attain it” (p. 55).

The German philosophers were interested in formulating ideo-motor theory as a general explanation of action control. Herbart’s(1816, 1825) views on ideomotor action are especially similar tothose of current researchers. He did not restrict ideomotor action toreflexive behavior, and he considered the role of learning in thedevelopment of ideomotor codes. According to Herbart, actionsare initiated by anticipation or desire of the to-be-produced sensoryeffects. He proposed a two-step process: (a) automatic associationof actions and their sensory effects when they are executed and (b)purposeful use of these associations to initiate actions and bringabout the intended action effects. Lotze (1852) and Harless (1861)expanded on Herbart’s views.

James (1890/1950) defined ideomotor action as “the sequenceof movement upon the mere thought of it” (p. 522), saying,“Whenever movement follows unhesitatingly and immediately thenotion of it in the mind, we have ideo-motor action” (p. 522). Hesuggested that the immediate or direct relation between “ideas”and movements is the critical factor to induce a voluntary move-ment by assuming that an action is represented in terms of thesensory form of its effect. According to James (1890/1950, p. 526),merely thinking of its effect image will activate the intended motorprogram: “Every representation of a movement awakens in somedegree the actual movement which is its object.” One reason whymovements will not occur in all situations is that “the bare pres-ence of another idea will prevent its taking place” (p. 527). Jamesattributed development of ideomotor action to the co-occurrence ofsensory input and action: “When a sensation has once produced amovement in us, the next time we have the sensation, it tends tosuggest the idea of a movement, even before the movement occurs”(p. 585).

Stock and Stock (2004) noted that although ideomotor theoryfell out of favor early in the 20th century, a few researcherspursued its implications in empirical and theoretical work. We willnot review the work that they covered but will describe Hull’s(1931) proposed solution to ideomotor behavior. Hull developedthe notion of anticipatory goal reactions, depicted as rG�sG, whichin his theory are representations of the goal reaction (RG) and theresulting proprioceptive stimuli (SG). He argued against the viewthat ideas precede and evoke acts. According to Hull:

In contrast to that view, the hypothesis here put forward is (1) thatideo-motor acts are in reality anticipatory goal reactions and, as such,are called into existence by ordinary physical stimulation; and (2) thatthese anticipatory goal reactions are pure-stimulus acts and, as such,guide and direct the more explicit and instrumental activities of theorganism. In short, ideo-motor acts, instead of being evoked by ideas,are ideas. (p. 502)

Thus, Hull (1931) emphasized the importance of the goal actionand resulting sensory feedback in his explanation of ideomotorbehavior. Hull’s analysis was given detailed coverage by Green-wald (1970) in his article that initiated the modern revival of

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ideomotor theories of action. Greenwald stated, “The fundamentalinsight in Hull’s rG�sG analysis was the use of sensory feedbackfrom an anticipated response as a mediator of performance” (p.78). However, Hull’s insight has not been credited in most subse-quent work on the topic.

A Modern Version of Ideomotor Theory: Greenwald’s(1970) Ideomotor Mechanism

Greenwald’s (1970) analysis of the ideomotor mechanism isgenerally regarded as a revival of James’s (1890/1950) ideomotorprinciple and a functional translation of James’s ideas into moreverifiable terms (e.g., Knuf et al., 2001). Greenwald contrastedfour different feedback mechanisms mediating voluntary perfor-mance: serial chaining, fractional anticipatory goal response,closed-loop mechanism, and ideomotor mechanism. In all mech-anisms, sensory feedback resulting from self-action is considereda crucial mediator in action control. Greenwald gave “specialreference” (p. 73) to the ideomotor principle and noted that it is abasic mechanism of voluntary action.

Greenwald (1970) suggested that the idea or image of a responseand contiguity of events are sufficient for instrumental condition-ing. According to his description of James’s (1890/1950) deriva-tion of the ideomotor mechanism, there are three significantevents1 (see Figure 1): Stimulus (S)–response (R)–effect/sensoryfeedback (E).

The S, R, and E events unfold in sequence across time, and theyare usually contingent or causally related to each other. If an agentgenerates a certain movement, action-dependent feedback willfollow. Unique triplets of S1–R1–E1, S2–R2–E2, . . . , Sn–Rn–En

occur repeatedly to an agent. By repeated exposure to the contin-gent triplets, the agent can associate the relationship betweenevents automatically to some degree. This association results in“conditioned anticipatory images of response feedback” (Green-wald, 1970, p. 85),2 denoted by the lowercase letter en, in Figure 1.Anticipatory images are conditioned to each contingent forthcom-ing effect and then finally acquire discriminative control over theircorresponding responses even without the original stimulus totrigger the responses. Anticipatory associations are chained be-tween the consecutive elements of the effect sequence so thatactivation of the anticipatory image triggers the anticipation of thenext effect to be produced, which in turn triggers the respectiveserial response. In the ideomotor mechanism, a motor command isexhaustively coded with the intrinsic feedback that it aims togenerate.

Greenwald (1970) suggested use of a two-phase experimentalmethod, practice and test, to investigate the ideomotor principle.For the practice phase, a participant is exposed to the contingenttriplets of S1–R1–E1 repeatedly, and the response (R1) is condi-tioned to the anticipatory image of distinctive sensory conse-quences (e1). For the test phase, the combined event of S1 with E1

is presented, and E1 is not a task-relevant stimulus to be per-formed. The response to the target stimulus S1 will be executedfaster and more accurately than in the control condition, which isa triplet of three events that has never been experienced before. Inthe last decade, the experimental paradigm consisting of practiceand test phases has become the main setting for investigations ofaction effects (e.g., Elsner & Hommel, 2001; Kunde, Koch, &Hoffman, 2004).

The Theory of Event Coding

The most influential ideomotor theory in recent years is Hom-mel, Musseler, Aschersleben, and Prinz’s (2001) theory of eventcoding (TEC), which is based on a common representationalsystem of perception and action codes. TEC is a theoretical frame-work rather than a fully articulated theory; some of its coreconcepts, such as event, are loosely defined, although the conceptshave been elaborated in later studies (e.g., Hommel, 2007b). Con-sequently, the theory is not easily falsifiable, as the authors men-tioned. They suggested that TEC’s empirical validity could betested within task-specific models derived from the general theory.TEC has been referred to in more than 300 articles and is regarded

1 The original alphabetical denotation that Greenwald used was partiallychanged to avoid confusion of terms used in this review. Uppercase lettersdenote overt external events, and lowercase letters denote covert internalstate.

2 Images refer to “central representations of sensory feedback fromresponses” (Greenwald, 1970, p. 84).

Figure 1. Panels a–d illustrate hypothetical associations in Greenwald’s(1970) ideomotor mechanism. Some of the denotation here was revised,but the basic structure is the same as in Greenwald’s article. The capitalletters denote the overt sensory (S for stimulus and E for effect) and motorevents (R), and lowercase letters denote internal images of perceivableevents. Automatic bonds between events are connected by solid lines, andconditioned bonds are connected by dotted lines. Thus, en representsinternalized image of forthcoming action effect. Repeated experience ofstimulus–response and following consistent action effect (Panel a) resultsin conditioned anticipatory image to a certain stimulus (Panel b), whichthen becomes anticipatory to the actual effect (Panel c). Panel d demon-strates that the anticipatory images eventually acquire the control over thesequence of the actions. Adapted from “Sensory Feedback Mechanisms inPerformance Control: With Special Reference to the Ideo-Motor Mecha-nism,” by A. Greenwald, 1970, Psychological Review, 77, p. 85. Copyright1970 by the American Psychological Association.

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as a powerful framework in terms of its heuristic and explanatorypower in general.

The following are TEC’s basic assumptions: (a) Perceived andto-be-produced events are represented in a common domain; (b)actions are represented in a similar distributed fashion as percep-tion; (c) the codes referring to the event are part of an abstract andcontents-driven distal description rather than a proximal referenceof the events; (d) event codes are integrated and activated bytwo-stage procedures; and (e) event codes are structured withseveral hierarchical levels. Hommel et al. (2001) noted that TECincorporates some components from older ideas, especially fromthe theorists who postulated an integrated relation between per-ception and action planning (e.g., Gibson, 1950). The originalideomotor principle (e.g., Greenwald, 1970; James, 1890/1950)also has been reinterpreted in more specific terms. The represen-tational structure of TEC is close to that of a cortical networksuggesting that features of the events, such as color, shape, andlocation, are activated in a distributed fashion (Allport, 1987;Singer, 1994). How these distributed codes are integrated into onecode that refers to one consistent event and how two differentcodes of stimulus and response can be represented within a com-mon domain are the key issues addressed by TEC.

Event File

How the brain encodes each feature of an object has beenstudied since the 1960s, and this research has shown the brainsystem to be highly segregated (e.g., Livingstone & Hubel, 1988).How these distributed features are integrated into one homogenousrepresentation, usually called the binding problem, has remained apuzzle. Behaviorally, Treisman and Schmidt (1982) and Kahne-man, Treisman, and Gibbs (1992) found that perceiving an eventautomatically induces binding of the individual codes representingit. Kahneman et al. refined the original feature integration theoryby claiming that feature-code bindings are integrated together withmore abstract semantic knowledge in an object file. As aknowledge-enriched structure of specific feature combinations, anobject file does not just register features of a perceived object butalso represents an episodic trace of a particular stimulus perceivedin a particular context.

TEC’s core concept of event is a more generalized form ofobject file. Event file refers to both perception and action descrip-tion. Hommel et al. (2001) defined event as “an easily discrim-inable, well-defined snapshot of the world or a single, discretemovement” (p. 864). Every external event, including one’s ownaction, is coded in an event file. Hommel et al. (2001; Hommel,2003) proposed that planning an action also should be representedin a manner parallel to how visual objects are represented andintegrated. Perceiving and action planning are functionally equiv-alent, inasmuch as they are alternative ways of doing the samething.

Distal Coding of Events

To represent action and perception in a common domain, thecodes should refer to distal events in the environment. Hommel(2009) commented that the distal concept is based on terminologyfrom Heider (1926/1959, 1930/1959) and Brunswik (1944), whodistinguished four different layers of the perceiving world. Ac-

cording to them, the outermost layer is D, which refers to objects,people, and events existing in the real world. These distal thingsare experienced as beings (D�) through transformation of physicalattributes of the things (V) such as light or sound energy, which isan incomplete copy of the things, into corresponding neural pat-terns by the sense organs (V�). The event code is a modality-freefunctional description of an object, which represents meaningfulinteraction of one’s action in the environmental context. Kahne-man et al. (1992) suggested that only a distal and contents-orienteddescription is functionally and practically usable to describe andcontrol an action consciously. MacKay (1982, 1987) also proposedthat the end processes of perception and action are highly segre-gated but that the cognitive level of the analysis communicateswith the same processing language and in the same way withperception and action. The fine-tuned motor command or reaffer-ent information hardly enters awareness.

Hommel et al. (2001) indicated that TEC’s theoretical scope islimited to the “late” cognitive products of perceptual processing(D� in the previously discussed terminology) and “early” cognitiveantecedents of action. Event codes for action and perception referto the same distal features in the environment, coded in terms ofthe perceiver-and-environment relation, including any body-related information. The concept of distal coding is analogous tothat of affordance advanced by Gibson (1950). Gibson regardedperception as a process of extracting invariant information aboutpotential contents of action in an optic array; therefore, action doesnot require transformation of the contents of the perceptual anal-ysis into actionable codes. TEC also suggests that action planningspecifies the codes of the intended action features, which areactivated when one perceives the stimulus; thus, complex adaptivevalues like walk-on-ability, grasp-ability, and sit-on-ability arepicked up in the course of perceiving.

Hommel et al. (2001) explained how codes are integrated in acommon system (see Figure 2). Two feature codes, f1 and f2,

Figure 2. Feature coding according to theory of event coding (TEC). Inthe example, sensory codes coming from two different sensory systems (s1,s2, s3, and s4, s5, s6, respectively) converge onto two abstract feature codes(f1 and f2) in a common coding system. These feature codes spread theiractivation to codes belonging to two different motor systems (m1, m2, m3,and m4, m5, m6). Sensory and motor codes refer to proximal information;feature codes in the common coding system refer to distal information.Reprinted from “The Theory of Event Coding (TEC): A Framework forPerception and Action Planning,” by B. Hommel, J. Musseler, G. Aschersle-ben, and W. Prinz, 2001, Behavioral and Brain Sciences, 24, p. 862. Copyright2001 by the Cambridge University Press.


denote “left” and “high,” respectively. These codes are made bylistening to a high-pitch tone from the left side: f1 receives anyperceptual input relating to “left” from the visual system (S1, S2)or auditory system (S4), and f2 processes information relating to“high” from visual system (S3) and auditory system (S5 and S6).Each sensory input or motor output refers to proximal information,whereas feature codes are represented in distal information. Anaction plan can be executed by activation of these feature codes.Activation of f1 may facilitate any “left” action such as saying“left” or moving the eye to the left. Thus, the feature codes controlall relevant effectors rather than being limited to a specific mode.Activating features f1 and f2 simultaneously produces a homoge-neous event code; thus, hearing “left” in a high-pitch tone willautomatically activate saying “left” in a high-pitch tone.

Remarks on the Ideomotor Mechanism

The core character of ideomotor accounts is that actions arerepresented in terms of their sensorial effects, which can be clas-sified in different manners. Greenwald (1970) categorized feed-back on the basis of the pathway used to transmit the sensoryinformation. Interoceptive feedback is delivered by propriocep-tion, including kinesthetic or muscular feeling of the movement; incontrast, exteroceptive feedback is delivered by visual, auditory,tactile, and olfactory pathways. Effects can also be categorized bywhether the source of information is from the actor’s own body orthe outside environment. Resident effects refer to the sensoryconsequences occurring with body movements, and remote effectsare the environmental consequences such as the flight of a ballafter one throws it (Hommel et al., 2001). In terms of Greenwald’scategorization, the visual feedback of the arm’s movement trajec-tory is exteroceptive, but in terms of the resident/remote catego-rization, it is resident. When the ball hits the body as a conse-quence of an action, this can be defined as interoceptive and alsoremote.

The ideomotor accounts take all types of effects into theirtheoretical consideration, Most ideomotor accounts do not specifywhich effect type is of concern in their theoretical structure, thoughmostly exteroceptive and remote effects are manipulated in theexperiments. Greenwald (1970) even suggested that his ideomotoranalysis could be generalized to extrinsic feedback, which iscontrolled by an outer mechanism such as reinforcement. Hommelet al. (2001) also conjectured that any kind of action-contingentevent (e.g., turning on a light, producing a tone, pressing a key)could be accommodated by its TEC account.

TEC’s proximal/distal concept is thought to be different fromthe resident/remote categorization, although Hommel et al. (2001)sometimes used expressions such as proximal effect. The defini-tion is not from the source of the effect or the sensory pathways butfrom the manner of the coding. As far as perception is concerned,the distal information (D) existing in the world is recovered (D�)even with arbitrary encoding (V�) of the physical attributes (V). Vseems to be inherently ambiguous and noisy, and V� lacks therichness of the real world, but the correlation between V and V� isassumed to be high, and the restoration (D�) is a veridical repre-sentation of the world (D).

Since only D� can be consciously accessed and D� refers to thesame D for action and perception, this level of information issuggested to be functionally usable to control actions. V layers are

involved in different types of neural activity for processing inputand output information and thus are incommensurate. Though thefeedback (action effect) is conjectured as a core dynamic force, theideomotor mechanism can be contrasted with the closed-loopmechanism, in which peripheral information of resident effects isused to update parameters of continuous movements (Adams,1971). Adams hypothesized that feedback from responses leaves aperceptual trace, which is used as a goal to be compared withcurrent performance. If incoming feedback signals a discrepancyfrom that goal, this difference results in error, and an individualcan adjust error by minimizing the difference between performanceand goal. Comparing and correcting error occurs until the movementachieves the final goal state. Hence, adjustment of motor executionemerges from a dynamic interaction between the motor system andthe environment. In contrast, the ideomotor principle emphasizes theprocess of selecting and initiating an action (Kunde et al., 2004),although some authors have suggested that the ideomotor mechanismalso serves an evaluative function in that the outcome of the perfor-mance is compared with the intended effect in real time (Band, vanSteenbergen, Ridderinkhof, Falkenstein, & Hommel, 2009; Nattkem-per & Ziessler, 2004).

Reflexive Behavior, Volition, and Consciousness

Another characteristic of ideomotor accounts is immediacy be-tween perception and action, which means that no intermediatesteps are required for motor transformation from idea. Thus, al-though ideomotor control is essentially endogenous action startingfrom a certain intention, it also includes motor activation from aphysically given stimulus such as sympathetic, induced actions andstimulus–response compatibility (SRC) effects. Seemingly exoge-nous control is included in ideomotor accounts because (a) themental and physical events are not dissociable (thus, the physicalevent is transformed into a mental representation) and (b) when thestimulus itself resembles its anticipatory image, the stimulus acti-vates ideomotor control.

With regard to the ideomotor characteristic of immediacy ofaction, the role of conscious intent in action control should beidentified (Westwood & Goodale, 2001). Because of the ill-defined nature of consciousness, the debate about what a consciousprocess is easily leads to an “agree-to-disagree” argument. Con-sciousness is often defined with a dichotomous description con-trasting it to un-, sub-, or nonconsciousness. Historically, in dual-process theory, controlled versus automatic processing has beenstereotyped as denoting conscious versus subconscious processing.Other terms used to represent consciousness include supraliminal,intentional, effortful, serial process, voluntary, intelligent, control-lable, accessible, and reportable. In contrast, terms used to repre-sent unconsciousness include subliminal, unintentional, effortless,parallel process, involuntary, dumb, uncontrollable, inaccessible,and nonreportable. However, this dichotomous approach has beencriticized. For example, Bargh and Morsella (2008) called uncon-sciously controlled behavior, such as highly skilled behavior with-out conscious guidance, intelligent adaptive unconscious behavior,breaking the boundary of the conscious/unconscious dichotomy.Also, Hommel (2007a) suggested the concept of automatic goal-driven behavior, saying that even an automatic process reflects acurrent task goal. Nowadays, even a more radical statement isbeing made: that the acts are essentially unconsciously activated

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and that the phenomenal experience of causality by free will is aperceived illusion (Haggard, Clark, & Kalogeras, 2002; Wegner,2003).

James (1890/1950), who was most responsible for promulgatingthe concept of ideomotor action in psychology, described action asfollowing “unhesitatingly and immediately” (p. 522) the idea in themind. In his view, no intervening mental operation (will) is nec-essary for evoking muscular movement from the idea of sensoryfeedback. James said, with regard to ideomotor action,

The question is this: Is the bare idea of a movement’s sensible effectsits sufficient mental cue . . . , or must there be an additional mentalantecedent, in the shape of a fiat, decision, consent, volitional man-date, or other synonymous phenomenon of consciousness, before themovement can follow?

I answer: Sometimes the bare idea is sufficient, but sometimes anadditional conscious element, in the shape of a fiat, mandate, orexpress consent, has to intervene and precede the movement. Thecases without a fiat constitute the more fundamental . . . . (p. 522)

Later in his book, James also stressed the tight link betweenperception and action, saying,

No impression or idea of eye, ear, or skin comes to us withoutoccasioning a movement, even though the movement be no more thanthe accommodation of the sense-organ; and all our trains of sensationand sensational imagery have their terms alternated and interpene-trated with motor processes, of most of which we practically areunconscious . . . . From this point of view the distinction of sensoryand motor cells has no fundamental significance. All cells are motor.(1890/1950, p. 581)

The mundane actions are supposed to be instigated by incomingsensations and fleeting ideas without interrupting other activities.

Carpenter (1852) also defined ideomotor action as reflexlikebehavior, for which the idea itself has impulsive features thatcorrelate to the neuronal activity, and thus the mere idea is suffi-cient to initiate action. Conscious intent to act is not an antecedentof the action. In both Carpenter’s and James’s (1890/1950) views,will seems to play a gate-keeping role to keep a certain action frombeing set in motion in an antagonistic way. This idea is echoed bymodern accounts in which control is treated as self-regulatory innature, inhibiting or suppressing inappropriate or unwanted re-sponses (e.g., Baumeister & Vohs, 2004). Thus, although an in-tentional property was included in the original ideomotor view toaccount for human behavior (as in the answer by James citedearlier), the ideomotor process tended to be treated as a more orless subconscious one.

The assumption of ideomotor action as a reflexive expression ofidea still existed in Greenwald’s (1970) version of the ideomotorprinciple, but recent formulations have placed relatively moreemphasis on intentional actions. In their characterization of ideo-motor views, for which their TEC is an example, Hommel et al.(2001) stated,

Ideomotor views stress the role of internal (volitional) causes of actionand at the same time disregard the role of external (sensory)causes. . . . In this view, actions are considered creations of the will—events that come into being because people pursue goals and entertainintentions to realize them. (p. 856)

They also indicated, “In TEC, event coding in perception andaction is highly (although not completely) dependent on the per-ceiver/actor’s current aims and goals” (p. 863).

Although Hommel et al. (2001) did not take an explicit stanceon the issue of consciousness, the terms volition, will, goals, andintentions that they use are typically treated as synonymous withconsciousness, as James (1890/1950) noted (see Hommel, 2007a,for an argument for distinguishing goal-driven behavior fromconsciousness). Definitions of volition include “the capability ofconscious choice and decision and intention” (“Volition,” n.d.-a)and “a conscious choice or decision” (“Volition,” n.d.-b), andgoal-driven behavior frequently is equated with conscious control(e.g., Umilta, 1988). Moreover, in Hommel et al.’s (2001) responseto commentaries on their article, they stated that TEC sharesseveral attributes of the ventral sensory stream, which is involvedin object identification (“what it is”) and closely linked withconscious awareness, rather than the dorsal stream, which providesinformation for guidance of action (“where it is”; Milner &Goodale, 1995):

The ventral stream of their [Milner & Goodale’s] model seems toshare several attributes with the perception-action system TEC pro-poses. It is assumed to work off-line to mediate associate learning, andmake use of its results, and to make sure that the animal’s behaviormeets emotional needs and social requirements. These features wouldmake the ventral stream a perfect candidate for mediating perceptionand action planning along the lines of TEC. (p. 925)

The link between the ventral stream and consciousness is suf-ficiently strong that Westwood and Goodale (2001), in a commen-tary on Hommel et al.’s (2001) article, labeled that pathway the“ventral stream of conscious visual perception” (p. 908). Given theterminology used by Hommel et al. and their relating TEC tothe ventral stream, it seems reasonable to say that TEC stressesintentional action of the type typically associated with conscious-ness more than most prior ideomotor views do.

Tests of the Ideomotor Principle

The ideomotor principle has been tested with several researchmethods. Recently, scientific inquiries into the ideomotor mecha-nism have been conducted mainly by the TEC theorists. Theseinquiries include (a) acquisition of associations between actionsand their effects in incidental sequence learning, (b) examinationof relations between actions and their effects in choice-reactiontasks, (c) comparison of SRC effects for sets with different ideo-motor relations, and (d) consideration of actions induced in anindividual by his or her viewing dynamic scenes or others per-forming actions. Also, some researchers who credited their formu-lations to James’s (1890/1950) ideomotor action have investigatedthe topic of consciousness (e.g., Aarts, Custer, & Marien, 2008;Bargh & Chartrand, 1999), and others the issue of how ongoingaction modulates encoding of a perceivable scene (e.g., Schutz-Bosbach & Prinz, 2007). We review this research in the followingsections.

Goal-Driven Action: Action–Effect Paradigm

Most of the behaviors people perform are intended to producecertain outcomes. For example, a driver turns a steering wheel


counterclockwise to turn a vehicle to the left, a person presses an“up” button to call an elevator to go to a higher floor, and so on.Current versions of ideomotor theory consider actions to be inev-itably goal driven and therefore view accounts of human behavioras requiring a larger role for the element of action effects than istypical.

Evidence about spontaneous acquisition of contingent relation-ships between actions and their effects has been provided inseveral studies (e.g., Elsner & Hommel, 2001; Hoffman, Sebald, &Stocker, 2001; Ziessler, 1998). The consensus of these studies isthat voluntary behavior is initiated by anticipation of the outcomeof the to-be-performed action. As Greenwald (1970) suggested inhis formulation of the ideomotor mechanism, the training phase ofacquisition of the associative relationship among stimulus–response–effect (S–R–E) and the test phase of measurement of thepriming effect of “E” to activate a certain response have been usedfor testing ideomotor theory.

One of the first experiments to investigate the role of actioneffects is that of Morin and Grant (1955), in which participantsperformed a task for which eight keypress responses (executed byeight fingers on keys) were made to the locations of eight redstimulus lights. A row of green lights mapped compatibly to theresponse keys was located immediately below the row of stimuluslights. When a key was pressed, it turned on the correspondinggreen light as an action effect. On each trial, two stimulus lightsappeared simultaneously to which their assigned keypresses wereto be made. For different participants, various S–R mappings wereused, including completely compatible, mirror-opposite, random,and four other mappings with intermediate positive or negativecorrelations between stimulus and response locations. Participantswere instructed to try to learn the mapping by matching theresponse lights to the stimulus lights.

Across nine blocks of 25 trials each, reaction time (RT) de-creased in all conditions but more so for the more difficult S–Rmappings. In a 10th block, for which the response lights weredeactivated, RT increased for all conditions except that with thecompatible S–R mapping. Morin and Grant (1955) noted,

In general, the amount of loss in performance efficiency seemed to bedirectly related to the difficulty during Blocks 1–9. It may be con-cluded, therefore, that the green lights provided important visualinformation and that their importance was directly related to thedifficulty of the task or the lack of correspondence between displayand control. (p. 43)

Thus, participants acquired knowledge of the relation betweenactions and their visual effects, which they used for controlling theaction when the mapping was not compatible.

There is currently a revival of interest in the idea of couplingaction and perception codes with more theoretically oriented ex-perimental investigations, and action–effect studies have becomeone of the primary domains for the study of the ideomotor prin-ciple. Two task paradigms have been used to elucidate the relationbetween action and effect. One is serial RT (SRT; e.g., Ziessler,1998), and the other is choice RT (CRT; e.g., Hommel, 1996). Inan SRT task, a sequence of stimuli and actions is repeated peri-odically, and benefits in performance of this repetition are exam-ined. SRT tasks are usually carried out to explore how skill isacquired from repeated coupling of actions and their effects, suchas a playing a musical instrument. In CRT tasks, there is no

systematic sequence to trials, and the emphasis is on associationsbetween actions and their effects. CRT tasks were motivated byGreenwald’s (1970) original ideomotor formulation of a two-stageassociation, and they have the goal of explicating the bidirectionalrelation between action and perception. Both paradigms assumethat all human behaviors are purposeful. In both tasks (reviewedlater), performance is usually better when a required response iscoupled with a unique outcome and the relation between actionand outcome is consistent.

The manipulation of action effect and its relation to other eventsis a key variable of interest. Historically, three events in series—stimulus, response, and outcome—have been identified as signif-icant in experimental trials. The relation between stimuli andresponses has been investigated extensively, but outcomes haveoften been omitted from theoretical interests, especially in humanbehavior. Experimenters typically offered the action effects asfeedback about whether the response was correct or incorrect.They did not consider in much detail the structure of outcomes intheir theoretical systems (Bush, Galanter, & Luce, 1963).

However, the manipulation of the reinforcer, that is, the actionoutcome, has been shown to be vital in producing learning inanimals and has been of longtime theoretical interest. Instrumentalbehavior is controlled by its consequences. If a response to astimulus offers a satisfying event, the response–stimulus (R–S)association is strengthened (the law of effect; Thorndike, 1905).After acquisition of the association between behavior and itscontingent consequence, an animal will perform goal-directedactions to influence the environment. A number of studies haveshown that animals are highly sensitive to changes of the outcomesituation, such as delay in delivery of the reinforcer, contingencyor contiguity of the reinforcer, and quantity and quality of thereinforcer (e.g., for contiguity, Lattal & Gleeson, 1990; for con-tingency, Caspy & Lubow, 1981).

When two discriminative responses are followed consistently bytwo different outcomes, animals learn to differentiate the twostimuli more quickly and accurately than if the same outcomeoccurs for both responses, a phenomenon called the differentialoutcome effect (e.g., Trapold, 1970; Urcuioli & DeMarse, 1996).The differential outcome paradigm has shown that the responseoutcome is not a passive motivator to induce an intended behavior,but rather it is a critical element of learning that modulates behav-ior. The implications from instrumental behavior for animal learn-ing seem to be relevant to voluntary action of human behavior.Hommel et al. (2003) suggested that the differential outcomeparadigm can be applied to evaluate bidirectional response–effect(R–E) mechanisms in human learning. Elsner and Hommel (2004)proposed that if associational learning of action effects is mediat-ing the selection of action, action selection should be influenced byfactors known to affect instrumental learning in animal behavior.They reported that the manipulation of contingency and contiguitybetween an action and its effect modulated speed and accuracywith which animals acquired the action–effect relation.

Also, ideomotor theory assumes that any perceivable feedbackresulting from an action can be formulated as an anticipatoryimage to initiate action, provided that the effect is reliably consis-tent with the responses (Greenwald, 1970). For example, effectssuch as tactile sensations and perceivable consequences of envi-ronmental change can be coded as anticipatory images. The kin-esthetic response effects from a keypress may exert control over

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response selection, and participants can learn an SRT task merelywith contingent tactile perception, without any reference to exter-nal events (Hoffmann & Koch, 1997). Though any perceivableevents can be associated with an action, Hommel et al. (2001)claimed that the common cognitive codes for action and perceptionrefer to the distal events. Only distal events can be coded at anabstract level and shared among different modalities, and distalcoding is the level to which TEC applies. A similar suggestion wasmade by de Wit and Dickinson (2009) in connection with animalinstrumental learning. They suggested that the intention to act isproduced by an interaction of a belief about a causal relationbetween the action and the outcome, influenced by the currentdesire for the outcome.

Resident effects are difficult to manipulate arbitrarily as inde-pendent variables (cf. ten Hoopen et al., 1982). Therefore, remoteeffects offered as results of actions are typically used to constructand evaluate theories related to action effects. In most experi-ments, auditory tone effects or visual display onsets have beenused as action effects. In the following, we examine action–effectstudies with regard to the ideomotor principle and show howevidence from those studies can help formulate the ideomotorprinciple in more precise terms.

Action Effect in Serial Reaction-Time Tasks

Nissen and Bullemer (1987) introduced what has become thestandard SRT procedure. In their study, participants made index-and middle-finger responses on four keys mapped compatibly to arow of four asterisks. The experimenters presented the stimuli in arepeating sequence of 10 elements without informing participantsof the event regularities. Performance improved across 10 blocksof practice for participants who received the repeating sequencecompared with those who received a random trial order. Whenparticipants in the repeated-sequence condition were tested with arandom trial order in the next-to-the-last block, their performancewas disrupted, indicating that the regularity of the stimulus–response sequence was incorporated into behavioral control. Thisincorporation seemed to have occurred automatically, since par-ticipants showed little awareness of the stimulus regularity. Aparticipant develops an internal model of the sequential structure,and this model is activated and applied to anticipate future events.The general procedure in which a repeated sequence is replaced bya random or deviant trial block has been used to measure learningin many subsequent studies (e.g., Koch, 2001; Koch & Hoffmann,2000; Ziessler, 1998).

The SRT task is considered to be an experimental analog ofskilled behavior in everyday life (Hoffmann et al., 2001; Ziessler& Nattkemper, 2001). The world presents predictable events by itsregular characteristics, and humans adapt to these structured ele-ments and prepare for upcoming events. Hoffmann et al. (2001)presumed that sensitivity to serial order should be regarded as acritical ability of an organism to adapt in the external world. Theknowledge about the sequence is consequently employed to selectthe correct action and accelerate its initiation.

What Is Acquired During Serial Learning?

Two main accounts have been proposed to explain what elementof a sequential structure is learned for skilled serial behavior. Some

researchers have argued that knowledge about the relation of thestimulus sequence is obtained by stimulus–stimulus (S–S) associ-ations (e.g., Cleeremans & McClelland, 1991; Lewicki, Czyze-wska, & Hoffman, 1987). According to this S–S–based learningaccount, a participant predicts a particular sequence of stimuli afterrepeated exposure to the systematic sequence. The other mainaccount is based on response–response (R–R) associations (e.g.,Nattkemper & Prinz, 1997; Ziessler, 1994). According to thisaccount, a participant learns motor execution in sequence, and thisknowledge is generated when a similar pattern of responses isrequired. Thus, the issue involves whether learning is mediated bythe perceptual system (S–S view) or the motor system (R–R view).However, a third (ideomotor) approach that stresses R–E learninghas also been proposed (Ziessler, 1998; called the R–S account).

In serial learning tests with a fixed sequence of stimuli thatrequire contingent responses, S–S, R–R, and R–S associations areconfounded (e.g., Nissen & Bullemer, 1987): The sequences ofstimuli, responses, and relations between the response and the nextstimulus all covary. Thus, which type of associational learningcontributes to control over the serial behavior cannot be deter-mined unambiguously with this method (Ziessler, 1998).

To find out which component is learned in a serial task, re-searchers must use a task in which the confounded changes ofstimulus and response sequences are dissociated. One method is toswitch the effector mode in a transfer phase after the sequencetraining. Cohen, Ivry, and Keele (1990) trained participants tomake three different keypresses to the stimulus sequence usingthree fingers of a single hand. After the learning curve stabilized,a transfer phase was introduced in which participants then pressedthe three keys using a single finger on the same hand. This changeof effector mode did not disrupt the serial learning acquiredpreviously, and Cohen et al. concluded that knowledge about thesequence of stimulus events is a key component in serial learning.However, selection of the response might occur not only at thephysical level of fingers but also at a more abstract level oflocation codes, with the representational structure being the samefor three fingers as for one. If the motor commands to controleffectors are changed more radically, serial performance may bedisrupted. This proposition seems convincing when one considersthat transfer of prior sequential knowledge is impeded when re-sponses are switched from manual to vocal (Keele, Jennings,Jones, Caulton, & Cohen, 1995).

Howard, Mutter, and Howard (1992) reported further evidenceof stimulus-based learning. They compared transfer performancefor an observational group that was exposed to the sequence ofpositional asterisk stimuli but not required to make any responsesand a responding group that made keypresses to the sequence ofstimuli. When the observational group was later required to re-spond to the sequence of stimuli, their performance was similar tothat of the responding group. For both groups, performance dete-riorated when a random sequence was introduced. Howard et al.concluded that the observational group had acquired the knowl-edge of event regularity purely by perceptual information and thatthis knowledge was sufficient to control the serial responses.

In contrast, Nattkemper and Prinz (1997) reported evidence infavor of response-based learning. They used an n:1 mappingmethod in which two stimulus letters were mapped to each of fourkeypress responses. Participants performed an SRT task composedof repeating sequences of eight elements, divided into two subsets


of four different letters. For each subset, the response sequencewas the same, meaning that it repeated every four trials. Occasion-ally, a deviant stimulus replaced one stimulus in the sequence.Performance deteriorated when the deviant stimulus led to a dif-ferent response than in the learned sequence but not when it led tothe same response. Therefore, the authors concluded that partici-pants acquired knowledge about response regularities, which ismore important than knowledge about stimulus regularity forcontrol of serial behavior. However, if a participant were to detectthat a fixed sequence of four responses was repeating within eachsequence of eight stimuli, he or she might choose not to attend tochanges of the stimuli but only to the sequence of responses.

The learning of R–S relations in serial behavior has receivedless attention than the S–S and R–R possibilities. However, theideomotor principle implies that R–S coupling is the key elementto obtain the knowledge of sequential structure (Greenwald, 1970).The chain of anticipatory feedback images of the to-be-performedsequence helps to trigger the sequence of actions in correct order.R–S–based learning is equivalent to ordinary performance inwhich people are doing something to bring about the outcome theydesire to achieve. For a typical example, a piano player presses thekeys to produce intended melodies, not merely to respond to thekeynotes. Stocker, Sebald, and Hoffmann (2003) stated that serialbehavior in our life is equivalent to producing a series of intendedoutcomes rather than responding to a series of stimuli.

With the previously described n:1 mapping solution to dissoci-ate covariation of response and stimulus, one risks inducing astrategy of not attending to the stimuli since the regularity of thestimulus sequence covaries with that of the response sequence. Toprevent this covariation, several researchers have adopted an am-bivalent stimulus to which participants respond (e.g., Cock &Meier, 2007; Koch, 2001). An ambivalent stimulus has two prop-erties, usually location and identity, one of which appears in asystematic sequence and the other at random. Participants are toldto respond to one stimulus property, the target property, and thisproperty can be dissociated from that of the other stimulus prop-erty, to which the participant is not to respond.

In their Experiment 3, Willingham, Nissen, and Bullemer (1989)had participants respond to the colors of the stimuli with key-presses. In one condition, the stimulus colors appeared with asystematic sequence while the stimulus locations appeared withrandom variation; thus, participants acquired the regularity of theirresponses (response–sequence condition). In another condition, thelocation of the stimulus appeared in a regular sequence withrandom variation of the color while the participants were stillrequired to respond to the color (perceptual–sequence condition).Thus, participants in this condition had no chance to learn asystematic motor sequence, but they might acquire knowledge ofregularity for stimulus location implicitly. Participants in theseconditions were compared with a baseline control group that waspresented randomly varying color and location sequences.

After the training phase, a transfer phase was introduced to eachgroup, which required participants to make keypresses to thelocations of the same-colored stimuli. The location sequence ofthe stimuli was the same in the perceptual–sequence condition, andthe required serial responses to the location were the same as thosein the response–sequence condition. Participants from theperceptual–sequence group did not show any advantage fromregularity of the target location, whereas participants from the

response–sequence group revealed a strong benefit from system-atic learning of their responses during training. This result seemedto favor motor-based learning; however, the response–sequencegroup did not respond faster when they were required to performthe same motor sequence in the transfer phase. Willingham andcolleagues concluded from these results that exclusively stimulus-or response-based learning does not exist and that mapping rulesunderlying the R–S pairing may be the critical component oflearning.

R-S–Based Learning Evidence from Ziessler (1998)

Though Willingham et al.’s (1989) study suggested that someR–S learning occurred in a serial task, the authors did not specif-ically examine the possibility for learning the relation between aresponse and its effect. Ziessler’s (1998) study has been widelycited as providing clear evidence of R–E association in seriallearning. Ziessler investigated the implicit learning componentsunderlying serial reaction tasks using a serial-search-and-reactiontask, originally devised in a previous study (Ziessler, 1994), whichwe describe first.

Ziessler (1994) had participants classify target letters (W, S, F,X) with keypresses made by the index and middle fingers of thetwo hands. Each trial consisted of presentation of a sequence of sixletter matrices composed of five rows of six letters each (seeFigure 3). For each matrix, one letter was the target for thatdisplay, and the remaining letters were not from the target set.Participants were to find the target letter and respond to its identityas quickly and accurately as possible. The presentation of thedifferent target letters was random, and thus there was no system-atic sequence of letter identities and responses to learn. For the firstdisplay in a sequence, the target letter was always in the centerposition. For the next display, the target letter could occur in anadjacent position above, below, left, or right of the current targetposition. Of importance, the current target identity indicated wherethe next target would be located. The target letter in the seconddisplay specified whether the target letter in third display would beabove, below, left, or right of it, and so on, until the sixth display.It contained a fifth target letter, to which a keypress with the rightthumb was to be made, indicating the end of the sequence. Par-ticipants were not told about the relation between the currentstimulus identity (Sid) and next stimulus location (Sloc), nor wasknowledge of this relation necessary to perform the task. However,if a participant acquired the relation between the current trial andthe upcoming event implicitly, he or she would locate the targetletter much faster than if he or she did not learn the relation.

After participants had performed moderately extensive practice(usually 2 hr) with these sequences, experimenters introduced adeviant session in the last experimental block to assess the partic-ipants’ learning of the relations of Sid and Sloc. For the deviantblock, the next stimulus appeared in the location opposite thatexpected on the basis of the prior relations. Sequential perfor-mance was significantly disrupted in this deviant block. However,the question of which knowledge of regularity was acquired stillremained because the relation of Sid and Sloc or current responseand upcoming Sloc covaried in the experiment. In Ziessler’s (1994)Experiment 2, the four critical target letters required a singlekeypress with the right index finger, and the fifth letter a keypresswith the right thumb; in this case, the disruptive effect of the

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deviant block was not sizable. If the same responses are made tothe different target letters, the relation between the current re-sponse and the next target location becomes unsystematic. There-fore, Ziessler concluded that learning of regularity between Sid andSloc in Experiment 1 was mediated mainly by knowledge of theresponse and its corresponding effect (the location of the nextstimulus).

Ziessler (1994) based his conclusion on comparison of his twoexperiments. However, the task in Experiment 1 was more difficultthan that in Experiment 2, because the four critical stimuli requiredunique responses in the former but the same response in the latter.This could result in participants from Experiment 1 being moreattentive to differentiating the identity of the stimulus, thus guidingS–S–based learning. To rule out this possibility, Ziessler (1998)manipulated R–S congruency by adopting the n:1 mapping proce-dure combined with a bivalent stimulus. He used a proceduresimilar to that in his previous study but with two letters assignedto each of the four responses. For the high R–S congruent condi-tion, the two letters assigned to the same keypress had the samerelation to the location in which the next target stimulus would

occur (see Figure 4, left column). The relation between the re-sponse and the subsequent stimulus location thus was unique inthis condition. For the R–S incongruent condition, the two stimuliassigned to the same response did have the same relation to thelocation in which the next target stimulus would occur (Figure 4,right column). For the medium R–S congruent condition, somedegree of congruency was still intact; for example, the left-handresponse always induced the next stimulus to be located at the leftor above the current one (Figure 4, middle column). Through thismethod, Ziessler could prevent covariation of the current trial’sstimulus and response to the next event while dissociatingresponse-based and stimulus-based learning.

If S–S learning is a critical factor in serial learning, the threecongruency conditions should not produce different performance,since the relations between the current stimulus and the nextstimulus for the three conditions are all unique. A similar predic-tion is made for R–R learning. However, if the regularity of thecurrent response and the next stimulus accounts for the reliableanticipation of controlling serial behavior, the R–S congruentcondition group should perform better than the groups in other

Figure 3. Illustration of Ziessler’s (1994) task. Example 1 demonstrates a six-element sequence (WFSFXV),and Example 2 demonstrates a four-element sequence (XSSV). At Time 1 (T1), the trial number was presented.The first stimulus followed at T2 in the middle location. The circled letters were target stimuli (the targets arecircled in the figure but were not in the experiment). After the stimulus “W” at T2, the next target appeared onelocation above the “W” at T3. Following the stimulus “F,” the next targets appeared at the relevant location ofone position left from the “F” (see T4 and T6). For responses, LI, LM, RI, LM, RM, and RTH denote left index,left middle, right index, left middle, and right middle fingers and right thumb, respectively. For the “different”conditions, response to each target letter was to be performed by each distinct finger, whereas for the “same”condition, same responses were required to be made for all targets except one. Reprinted from “The Impact ofMotor Responses on Serial Pattern Learning,” by M. Ziessler, 1994, Psychological Research, 57, p. 33.Copyright 1994 by Springer.


conditions. This result was found in Ziessler’s (1998) Experiment1. In addition, the R–S congruent group’s performance was moredisrupted by presentation of a random or reversed R–S relationshipblock, which is also evidence of using knowledge of R–S congru-ency to locate the target in the next matrix. Ziessler concluded thatthe coupling relationship of action and its effect is a key contrib-uting component for controlling serial action.

Ziessler and Nattkemper (2001) also examined whether R–Slearning is a key element to obtain skillful serial learning byadapting Nissen and Bullemer’s (1987) paradigm. They found thatlearning and transfer effects occurred when the R–S relation wassystematic but not when the S–S relation was. Ziessler, Nattkem-per, and Frensch (2004) further investigated the nature of the R–Slearning mechanism by presenting distractor tones during responsepreparation or between response execution and presentation of theeffect (the next target letter). The R–S learning was disrupted whenthe distractor occurred during response preparation but not afterexecution, which Ziessler et al. attributed to impairment of antic-ipation of potential effects. In a second experiment, they alsofound that the learning of R–S relation was not strictly automatic.Ziessler et al. accomplished this by having a letter and a digitproduced as action effects by each keypress response and instruct-ing participants to produce letters or digits. R–S learning wasfound only for the instructed effect category. Ziessler et al. con-cluded that an anticipated effect is generated during the prepara-tion of response and that learning of action effect proceeds selec-tively only for the events that contain the intended effect.

Ziessler and Nattkemper (2002) and Ziessler et al. (2004) pro-posed the anticipative learning model through their R–S associa-tion studies. This model explains the role of anticipatory effect inthe way of an evaluative function, which compares the observedoutcome (actual effect) against the intended outcome (anticipatedeffect) following a particular action. Two different behaviors,cue-driven (forward model) and goal-driven (inverse model), areformulated in an integrated system (see Figure 5). The termsforward and inverse are used in a manner parallel to Wolpert’s(1997) computational model of motor control. The forward modeluses an efference copy to predict the sensory consequences ofmotor commands. The inverse model provides the motor com-mands to make adjustments to achieve the desired outcome. Theinteraction between the inverse and forward mechanisms evokesthe anticipative model mechanism.

Serial Learning Task With Irrelevant Action Effect

The SRT tasks described previously are based on the seriallearning method introduced by Nissen and Bullemer (1987), inwhich the learning effect is measured by inserting a deviant block.In those studies, the stimulus has two components at the sametime: an outcome resulting from the response and a target stimulusto which a response is to be made for the next trial. Otherresearchers have investigated the role of a perceivable action effectby dissociating the action effect from the target stimulus in a serialtask (e.g., Drost, Rieger, Brass, Gunter, & Prinz, 2005; Hoffmann

Figure 4. Ziessler (1998) manipulated the response–stimuluslocation(R–Sloc) congruency by assigning differentpairings of stimuli to the same response. LI, LM, RI, LM, RM, and RTH represent the effectors left index, leftmiddle, right index, left middle, and right middle fingers and right thumb, respectively, in the same way as inFigure 3. Arrows denote the relevant position of the next stimulus from the current target location. For high R–Sregularity, two stimuli to which the same keypress response was to be made were followed by the next stimuluslocated to the left of the current stimulus. For medium R–S regularity, the next stimulus appeared in one of twoadjacent locations for which certain locational features were still intact (e.g., consequent target locations after leftkeypresses were always to the left or upward). For low R–S regularity, the next target location was unrelated thekeypresses made in the current trial. Reprinted from “Response-Effect Learning as a Major Component ofImplicit Serial Learning,” by M. Ziessler, 1998, Journal of Experimental Psychology: Learning, Memory, andCognition, 24, p. 966. Copyright 1998 by the American Psychological Association.

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et al., 2001; Pfordresher, 2005). Participants in those studies per-formed an SRT task, and the task-irrelevant action effect waspresented solely to the response. In most studies, auditory toneshave been used as action effects3 because when visual actioneffects are irrelevant, participants may fail to attend to the effects,whereas an auditory tone tends to attract attention (Hommel et al.,2003).

Hoffmann et al. (2001) used an SRT task similar to Nissen andBullemer’s (1987) but with distinct irrelevant tone effects trig-gered by the responses. Faster learning was produced when thetone effects were contingent than when they were not, and thelearning was disrupted more for the contingent group when arandom block was inserted in the ninth block. Hoffmann et al. alsoreported that only the contingent group showed disruption ofperformance when the tone effect changed into another mapping.The tone effects influenced serial learning only when participantswere given sufficient time to anticipate them. Hoffmann et al.suggested that the redundant tone effects facilitate establishing thesequential structure of the events.

Serial tasks with irrelevant tone effects are analogous to musicalperformance, such as piano playing, which requires a correct orderand timing of keypresses to bring about an intended melody orchord. Drost et al. (2005) reported that pianists responded to theimperative stimuli faster and more accurately when congruenttones followed them. Usually in the piano-playing studies, perfor-mance of novices was compared with that of trained pianists (e.g.,Finney & Palmer, 2003). Pfordresher’s (2003, 2005) studies dem-onstrated that the difference in performance between novice andtrained players is in the initiation timing of the action, not in actionselection.

One of the simplest ways to evaluate the role of tone effects inserial behavior is to compare performance between conditions withcontingent auditory feedback and with no feedback. The size of

disruption is usually measured by response rate and serial orderingerrors. It is rather surprising that several researchers have reportedthat performance in a serial task was unhindered by the absence offeedback (e.g., Finney & Palmer, 2003). However, many othershave found disruption of serial performance when the actioneffects were distorted in some manner. Presentation of alteredfeedback with unrelated contents or randomized feedback from theplanned action did not cause serial performance to deteriorate(Finney, 1997), but when a delay was added for auditory feedbackonsets, sizable disruption was induced (e.g., Pfordresher, 2003).

Pfordresher (2005) presented altered feedback by offering toneeffects in synchrony. Altered feedback was identical to the stim-ulus sequence structure but with a serial shift (i.e., number ofevents separating current action and its following tone effects).Disruption of performance depended on similarity of the plannedsequence and the sequence of sensory effects. Maximal disruptionoccurred when the feedback sequence structure was identical, butthe sequence was serially shifted so that a lag of one was addedbetween the current action event and the associated feedbackevent. The least disruption was brought out by randomly selectedtone effects or an absence of feedback. When the tone pitches wereselected by scrambling the order of the tones among those of theplanned action, the disruption was larger than if the tones did notmatch the planned action at all. Pfordresher concluded that dis-ruption increased as the sequence of the altered feedback eventsbecame more similar to the sequence of the planned action. Thedisruption by altered feedback contents only influenced the errordata, and the timing of the execution was not different among thevarious feedback conditions. Thus, the altered feedback disruptedselection of action but not the timing of execution. This impliesthat altered auditory feedback hinders planning (related to accu-racy) but not execution (related to timing).

Pfordresher and Palmer (2006) also used a task that requiredmanual keypresses to serial stimuli with altered feedback from theplanned sequence. The feedback of the current event was from thecontingent effect of the past action (delays) or future event (pre-lays). The serial separation between the current event and theplanned position of auditory feedback was also varied from one tothree. Performance was disrupted by almost the same amountregardless of the manipulation of direction or distance. The authorssuggested that a match of planned and perceived outcomes is basedon a global level, such as structural similarity, including the localmatches between individual planned and perceived events. Thisexplains why performance was drastically disrupted by a serialshift. Pfordresher’s (2003, 2005; Pfordresher & Palmer, 2002)findings imply that a person performs a serial reaction with respectto matching individual feedback to the planned action and feed-back about the series of actions to the global structure.

These findings of altered feedback agree with the hierarchicalcoding assumption of perception and action made by Hommel etal. (2001) for TEC. Planning action and perceiving action arecontrolled by the same representation, and this common represen-tation is hierarchically structured. Representation of sequentialbehavior is typically considered to be hierarchical (e.g., Colwill &

3 There are some exceptions. Hommel (1993) coupled light flash effectsat different locations for actions in different locations. Kunde (2001b) usedpositioned visual effects to the manual responses.

Figure 5. Anticipative learning model of the role of action–effect codesin action control. A stimulus directly activates response planning, whichresults in execution of the action and occurrence of some environmentaleffect. A desired effect based on goals activates the response planningappropriate for achieving the effect (inverse model). The effect that exe-cution of the activated response plan is likely to produce (forward model)is compared with the desired effect. Differences between desired andanticipated effects provide a basis for modifications of the response plans.Reprinted from “The Role of Anticipation and Intention in the Learning ofEffects of Self-Performed Actions,” by M. Ziessler, D. Nattkemper, and P.Frensch, 2004, Psychological Research, 68, p. 174. Copyright 2004 bySpringer.


Rescorla, 1990; Rosenbaum, Kenny, & Derr, 1983). In a simplerversion of the hierarchy assumption (Pfordresher, 2005), the levelsare supposed to be two tiered, consisting of individual events andtheir organization. Participants integrate auditory feedback into aplan of action, and they are sensitive to matches between theplanned and perceived actions. In a hierarchical representation, asequence is coded as a series of groups, with each group beingmore finely divided at a lower level. This group coding is some-times revealed by the pauses between subgroups of a motor se-quence (e.g., Rosenbaum et al., 1983), the RTs to prepare move-ments for execution (e.g., Klapp, Anderson, & Berrian, 1973), andpatterns of errors and transfer from one sequence to another (e.g.,Gordon & Meyer, 1987; MacKay, 1982).

Explicitly, Pfordresher and his colleagues addressed this issueby disrupting the serial performance through alteration of thestructure of the feedback sequence. When the perceived event ismatched with one of the to-be-performed actions, it activates theindividually associated action representation. However, removingfeedback or distorting it by random presentation of tones fails toaccess any individual or organized representational code of theplanned action and hence leads to intact performance. As analtered structure of the auditory effects becomes closer to theorganization of a planned action, it activates the higher order ofstructural representation, such as the planning of the event se-quence. Therefore, the global level of mismatch will lead to drasticinterference on performance for the case of serial shift. Pfordresherand Palmer (2006) suggested that both past and future events canbe simultaneously accessible through the hierarchical representa-tion system, if those events are linked at a higher level.

Hoffmann et al. (2001) found that when the keypress responsesare assigned compatibly to the response effect, serial responses arefaster than when they are assigned in an incompatible manner. Forexample, responses were faster for the ascending pitch tone effectsto the compatibly assigned keypresses from left to right than inmixed R–E mapping or descending right-to-left R–E mapping.Contingent tone effects only became effective when there wassufficient time for participants to anticipate the next to-be-produced tone before the next response signal was presented.

Disruption from distortion of the feedback signals can be foundin other domains of motor behavior. One can freely and compe-tently speak without the auditory feedback resulting from self-speech. However, the presentation of delayed auditory feedbackdisrupts performance: For example, a 200-ms delay of feedbackinduces hesitations and repetitions similar to stuttering (MacKay,1986). Asynchronous feedback induces disturbance of perfor-mance in speech (e.g., Howell & Powell, 1987) and tapping (e.g.,Chase, Harvey, Standfast, Rapin, & Sutton, 1961). However, elim-ination of feedback does not seem to impede motor performancefor rapid movements. Several studies also showed that participantscan point at a target without visual information feedback with onlyminor reduction of accuracy (e.g., Carlton, 1981).

Comparable results also can be found in deafferented insects oranimals. Eliminating feedback has been shown to produce negli-gible disruption of motor behavior in animals (e.g., Bassler, 1983).Destroying sense organs that signal leg position did not producedisruption of walking movements for insects, and monkeys withdorsal root section showed no impairment of motor performance.However, distortion of the sensory feedback provoked drasticdisruption of motor performance; for example, when the organs

signaled incorrect forward leg position signals continuously, in-sects failed to initiate the swing movement of walking (e.g.,Bassler, 1977, 1987).

Serial Learning in Animals

Learning of complex mazes, in which different responses aremade at different choice points, may be considered a variety ofserial learning. Early in this task, animals make incorrect as well ascorrect responses, and thus response patterns from one trial to thenext differ, while, of course, stimuli from trial to trial remain thesame. Consequently, early in training response learning is pre-cluded while learning on the basis of stimuli is possible. Later intraining, when the animals have learned the task, response learningas well as stimulus learning may occur. The animal literaturecontains many reports of efforts to determine the extent to whichserial responding in complex mazes is due to stimulus learning orresponse learning (Munn, 1950). This issue has also been raised inexperiments involving simpler mazes with a single choice point,most particularly, the cross maze (Restle, 1957). In a cross maze,the animals may be started from the north or the south and requiredeither to turn always to the west (stimulus learning, also calledplace learning) or to turn to the west when started from the southand to the east when started from the north (response learning).Place learning requires the animals to make two different re-sponses to get to the same place and, therefore, implicates stimuluslearning, whereas response learning requires the animals to makethe same response (left turn or right turn) at the same choice point.

The data from both complex and simpler mazes appear to beconsistent. When abundant visual stimulation is available, stimuluslearning predominates. When such stimulation is absent, as, forexample, when animals are tested under conditions of low illumi-nation, response learning predominates. Whether response learn-ing involves S–R or R–S relations or both is not clear from thesedata. In any event, it seems to be generally accepted that whetherresponse learning or stimulus learning predominates in such situ-ations depends on the conditions of the test, many of which aredescribed in Munn (1950) and Restle (1957).

The animal literature indicates that both stimulus learning andresponse learning may occur, and which is more important in aparticular case depends on the conditions employed. ThoughZiessler (1998; Ziessler & Nattkemper, 2001) has provided evi-dence that R–S learning predominates in many situations used tostudy human serial learning, the maze research suggests that S–Sand R–R learning may also occur in situations more favorable tothose relations.

Action Effect in Choice Reaction-Time Task

Another paradigm used to study the role of action effects inmotor control is the CRT task (e.g., Aschersleben & Prinz, 1995;Hommel, 1993). A participant is to select a correct response to aspecific stimulus among alternatives and execute it for each trial.Contrary to the serial learning task, a response is not related to thesubsequent trial in any systematic manner. Greenwald (1970)suggested that two stages of training and testing of associationalknowledge of action and action effect would be adequate to verifyideomotor theory. His suggestion is analogous to the tasks studiedby animal learning researchers. It consists of two sessions:

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training–acquisition phase (S–R–E relational learning) and testphase (test of acquisition).

Prototypical Two-Stage Action-Effect Procedures

Hommel (1996) had participants perform a speeded CRT task.For a training phase, left (R1) or right (R2) keypresses were madeto the letters, O (S1) or X (S2), respectively. The responses werefollowed by low (E1) or high (E2) pitch tones according to theresponses made. By repeated exposure to the stimulus–response–effect in series (S1–R1–E1 and S2–R2–E2), participants spontane-ously acquired the contingent relations among them. According toHommel, participants should form an association between themotor pattern underlying the action (r1; denoted as lowercase torepresent internal process) and the cognitive representation of theaction effect (e1), which is a bidirectional relation (r17 e1). If thisassociation is formed, presentation of one of the effects will primethe activation of e1 and eventually spread the activation to thecorresponding motor pattern. To test this facilitation, Hommelprovided the high or low pitch tones randomly with the stimulusletters (e.g., S1 � E1 or S1 � E2). When the tone effects corre-sponded with the required responses, the keypresses were madefaster as predicted, though E1 was task irrelevant and participantswere not informed of its purpose.

Hommel’s (1996) study was simple, and he used methodologythat captured the gist of the ideomotor hypothesis. However, sinceeach S–R–E triplet is unique, interpretation of the results is un-clear. The association between S and E might affect action selec-tion in the test phase rather than R–E learning, as ideomotor theoryargues. Therefore, Elsner and Hommel (2001) discarded presen-tation of unique S–R–E triplets in training and implemented a freeCRT task. Participants were told to respond to a nondiscriminativestimulus (go signal) in training. They were allowed to press keysarbitrarily, left or right, to this go signal, while trying to make eachresponse equally often. The contingent tone effect for each re-sponse followed, such as a high pitch tone for a left keypress anda low pitch tone for a right keypress. Thus, participants wereprevented from learning unique S–R or S–E associations; only theR–E association was contingent.

During the test phase, participants were also required to make afree-choice action to a go signal, and the effect tones were ran-domly provided with the go signal. The priming effect of task-irrelevant tones was evident in both action-selection speed and thefrequency of choosing the contingent action. Participants weremore likely to make a compatible response to the task-irrelevanttone effects, although they had never been required to do so before.The priming effect of tones was stable during the test phase, eventhough the action effects were not continued in that phase. Theprocedure of a free-choice task for training R–E association hasbeen applied in other studies (e.g., Kray, Eenshuistra, Kerstner,Weidema, & Hommel, 2006). Rescorla (1995) trained rats toperform instrumental behavior that was followed by distinct out-comes and tested their associational knowledge. He found thatR–E association was quite robust, even after extinction procedures.

Action Effect Impacts Action Preparation

Kunde, Hoffmann, and Zellman (2002) found that execution ofan unprepared action was easier if the sensory effect was identical

to the prepared action. Participants were required to make fourdifferent keypresses to four colored stimuli. The responses werefollowed by contingent tone effects, following the n:1 mappingmethod for which two different responses triggered the same tone.After this training, a response-preparation paradigm was intro-duced in which a cue informed the participant of the color of theupcoming stimulus, shortly before it appeared. Only 75% of thecues were valid; thus an unexpected color stimulus was presentedon 25% of the trials. Kunde et al.’s interest was performance onthose invalid trials, which revealed how prepared action can beswitched to to-be-performed actions by formerly associated toneeffects. Two different conditions relating to action–effect mappingoccurred in invalid cases. For the corresponding condition, theto-be-performed action and cued-action shared the same pitchtone, whereas for the noncorresponding condition, they did not. Asimplied by the ideomotor principle, participants more easilyswitched the misinformed movement to the to-be-performedmovement when the two resulted in the same tone effects.

Kunde et al.’s (2002) other experiments also supported thecollateral facilitation hypothesis. Participants were required toprepare the cued action to one stimulus, and the next stimulus waspresented after various time intervals following the first stimulus.Participants were to make the two responses in series as soon asthey saw the second stimulus, and the second stimulus remainedvisible until the second response was made. When the sequentiallyexecuted responses shared the same sensory effect, facilitation wasfound that was larger when the interval between the two stimuliwas short. This outcome implies that the action effects influencedearlier rather than later phases of action preparation.

Redefining Action With Newly Acquired Valence

Previous studies have shown that action effects are automati-cally acquired and integrated with the action control system bybilateral association of action and contingent effect. Action can beredefined with any perceptual quality or even with abstract emo-tion through the repeated pairing with specifically designed actioneffects. A typical Simon task offers a stimulus that has two distinctproperties, such as color and location. Participants are to make achoice reaction to one stimulus property, called the target property,and the other property is referred to as task irrelevant. Usually therequired action has no overlap with the target property but doeswith the task-irrelevant property. The activation produced by thislatter relation causes some internal competition. For example, aparticipant is usually required to make spatial keypresses to thecolor of the stimulus, which is in a left or right location. Perfor-mance is better when the stimulus location corresponds with, andactivates, the same response as that to the target than when itactivates a different response (called the Simon effect; Simon,1990).

Hommel (1996, Experiment 2) introduced a combined versionof Simon and action–effect tasks. The set-up was similar to atypical Simon task, except that the required response set did notoverlap with the stimulus set (positioned color stimuli). The re-sponses were spatially neutral actions such as pressing a key onceor twice in response to the color of the stimulus. Otherwise, acontingent action effect overlapped spatially with the property ofthe stimulus. When a compatible mapping between stimulus andeffect occurred, such as left-side effect to the left stimulus, action


initiation was facilitated. Action codes were automatically inte-grated to the perceivable effect features. Spatially neutral actionswere “spatialized” by repeated pairing with location action effects.

This assumption of automatic creation of bilateral associationsand strategic application became essential parts of Elsner andHommel’s (2001) two-stage model.4 This model adopts assump-tions equivalent to Greenwald’s (1970) ideomotor principle, whichexplains how knowledge of the action–effect relationship is ac-quired (Stage 1) and how the anticipatory images exert controlover the selection of voluntary actions (Stage 2). The contingentrelation between the action and the effect is acquired in Stage 1.Randomly generated action will always lead to a unique andparticular sensory feedback. Perceiving several co-occurrences ofa self-produced movement and a movement-contingent event leadsto an obligatory and spontaneous association between them due toa sort of trace conditioning. The motor pattern is voluntarilyselected by activation of the perceptual codes in Stage 2. Thoughseveral intentional steps may be necessary to complete activationof the motor code, the spreading of activation in a distributedfashion by an anticipatory process is assumed to occur. However,Hommel (2004) suggested that activation of the motor pattern byway of acquired action effect is intentional and guided by context.

Hommel (2004) developed a manual version of the Stroop taskcombined with an action–effect task. During the learning phase,participants made left and right keypresses to letter stimuli withina gray frame. After a correct response, the color of the target letterchanged to provide an action effect. Each keypress mapped to acontingent action effect, for example, right keypress mapped to thered effect and left keypress to the green effect. In the test phase, thetarget was presented with a color frame. Although participantswere informed that the color frame was irrelevant, the colorfacilitated the action with which it had been coupled previously.Through the repeated experience of action and contingent coloreffects, the color-relating event became an efficient prime toinduce spatial action, which Hommel called “coloring an action.”

After the coloring of an action, participants were introduced toa manual version of the Stroop task in Experiment 2. The questionwas whether action coding in terms of color-related events isautomatic or strategic. In the test phase, participants pressed a leftor right key to the color of the color word, the two of which werecongruent or incongruent. There were three color–effect condi-tions: compatible (e.g., left keypress to red color produced a redcolor patch), incompatible (e.g., left keypress to red color pro-duced a green color patch), and control without color effects. Onlyfacilitation from the compatible R–E mapping was found: RT wasshorter in the compatible condition than in the other conditions,which did not differ. If action effects automatically reidentify theaction in terms of the color, the incompatible color–effect condi-tion should show interference of similar size to the facilitationfound for the compatible condition. But if use of the action effectfor action selection is strategic, performance should be affectedonly when the action effect is helpful. Hommel concluded thatacquisition of the action–effect relation occurs automatically. Incontrast, activation of a relevant action code is context specific andstrategic. The Stroop effect was found in the incompatible coloreffect and control conditions but not in the condition in whichcompatible color effects were provided after the keypresses, withshorter RTs for both congruent and incongruent trials.

Hommel (2004) explained that acquisition of the relation be-tween action and its color effect causes participants to redefinetheir actions in a less linguistic way in terms of color, which“keeps linguistic distractors out of the processing pathway andrenders them ineffective” (Hommel, 2004, p. 83). This process isnot semantically mediated, since the Stroop effect was producedwhen congruent color words were presented as action effectsinstead of color patches in Experiment 3. Figure 6 provides anillustration of how color-relating events acquire almost equal abil-ity to induce spatial action as a spatial stimulus does. Mainly twotypes of feedback are produced (see Figure 6A). One is anydirectional property of feedback that occurs on the left or rightfrom a visual or tactile medium. The other is artificially providedby the color effect. An association of the action and its perceivableeffects is created spontaneously by overlapping two events tem-porally. Hommel (2004) wrote,

If people have no means of controlling the way they code theiractions, the left-hand action, say, would always be coded as both leftand blue, so that left stimuli and blue stimuli would make equallygood action primes. However, given the finding that instructing peo-ple in a particular fashion can make them code a left-hand action asRIGHT, and vice versa (Hommel, 1993), we need to assume thatactors have considerable control over how actions are coded. If so,participants in the present experiments must have had a choice be-tween “attending” either the location features or the color features oftheir key presses (i.e., of the key press-contingent perceptual events;see Hommel, 1993, 2003). (p. 85)

The color effect codes are automatically associated with themotor codes. Once the bilateral association is formed, a left orright action is assumed to activate both codes of color and location(see Figure 6B). The opposite direction of activation is also pos-sible: color or location events can trigger left or right motorpatterns to some degree. Action acquires two types of valence, onebeing the original directional feature and the other the color, butparticipants can selectively attend to the properties of their actions.If a required task does not relate to a color event at all, there is noreason to switch on the color domain. However, for Hommel’sstudy, participants performed a manual version of Stroop task,which necessarily required color-related processing. For this case,participants should prevent some degree of activation from thecolor domain to make a correct manual response. Facilitation fromthe compatible R–E mapping and no impact from the incompatiblemapping support this idea.

Beckers, De Houwer, and Eelen (2002) reported a similar phe-nomenon in which action is redefined with an action-irrelevantfeature by a newly acquired action– effect association. Theyadopted the affective Simon task originated by De Houwer andEelen (1998), who found that responding was facilitated whenparticipants were to say “Negative” for a noun when the noun hadnegative rather than positive meaning and to say “Positive” for theopposite situation. Beckers et al. told participants to make afree-choice reaction by moving a key upward or downward to a gosignal, while keeping the frequency of each response approxi-mately the same. One of the two responses triggered aversive

4 Note how this assumption is different from the view of Ziessler et al.(2004), who stated that the process for acquisition and application of actioneffect is quite selective and strategic to the context.

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electrocutaneous feedback. In a subsequent forced-choice taskphase, participants were to decide whether a word was a noun oradjective with the same response set (upward or downward). Whenthe word’s affective connotation corresponded to the key re-sponse’s valence acquired during the training phase, initiation of aresponse was facilitated.

These studies imply that any distal effects can be coupled withthe action. An intended action can be elicited not only by the

physical property of the response effect but also by a more abstractsemantic feature that was not directly observable. Once feedbackfeatures are integrated into a common cognitive structure, theactivation of a certain motor code is even generalized to semanti-cally related actions. Let us assume that whenever a spatiallyneutral keypress is made, a left-positioned visual stimulus is pre-sented. By this procedure, a neutral keypress acquires the “left-ness” value. The activation of leftness code is not limited to thespecific context of the setting in which the original relation wasestablished. If any “left” context is given to a participant such asuse of the left hand, or turning to the left or even saying “left,” theaction code of leftness will be activated to some degree.

Spreading Activation of the Acquired Valence

Hommel et al. (2003) carried out a free CRT task for anacquisition phase in which each keypress led to a contingent wordeffect. Words were category names (e.g., animal) or exemplars(e.g., dog). After participants completed the acquisition trials, atest phase of forced-choice reaction task was introduced. When theresponse effect was compatible with the stimulus for the test phase,pronounced facilitation was found, as in prior studies. This effectgeneralized to other exemplars in the same category (e.g., cat) andto words referring to a perceptually similar attribute in anothercategory (e.g., circle for orange). Hommel et al. concluded that aword in the acquisition phase can spread its activation to similarwords, allowing an extra relation between newly activated wordsand a particular motor command to be formed. Thus, the associ-ation with similar concept and a particular action is created auto-matically in the acquisition phase.

Endogenous Activation of Anticipatory Image:Action–Effect Compatibility

After establishing a bidirectional association of action and ef-fect, an actor can initiate the voluntary action by anticipation of theaction’s effects. The facilitation from e1 to r1, e1 3 r1 (actionselection by the anticipatory process), is the most distinguishingassumption of the ideomotor principle. Greenwald (1970) pro-posed that a sensory image of the effect is incorporated into theideomotor mechanism so that this internalized image of the sen-sory feedback exerts control over the action rather than controlbeing exerted by the sensory feedback itself. Once a person ac-cesses this image or “thinks” of an intended effect, it primes theaction to some degree and the action will follow. Therefore, theideomotor principle works as an endogenous process, not like anexogenous cue-driven process. However, this endogenous processis not addressed within the two-phase action effect paradigmpreviously introduced. Elsner and Hommel (2001) physically of-fered an action effect as a redundant but task-irrelevant stimulus inthe test phase. Their study provides evidence that a participantacquires a certain association between the response and the pos-tresponse effect but for the endogenous characteristic of the ideo-motor principle, according to which action is generated via accessto the image of the sensory consequence. As noted by Kunde(2001a), “Ideomotor hypothesis explicitly claims that voluntarymovements are selected by future (anticipated) but not by present(perceived) effects” (p. 387).

Figure 6. Illustration of how bilateral association between action andeffect is formed and finally controls the keypresses. Panel A shows thatperforming keypresses can bring about two different action effects, thelocation and the color. After several trials of consequent action effect,performing the action would bring about the anticipatory effects of locationand color, and any perceivable stimulus that relates to a certain color orlocation also would trigger a certain movement, which is sketched in PanelB. Reprinted from “Coloring an Action: Intending to Produce Color EventsEliminates the Stroop Effect,” by B. Hommel, 2004, Psychological Re-search, 68, p. 86. Copyright 2004 by Springer.


Kunde (2001b, 2003; Kunde et al., 2002, 2004) sought to assesswhether this endogenous anticipation indeed occurs. If the antic-ipated image works as a “mental cue,” this cue also may havesimilar features to those of a physically presented cue. For in-stance, when there is dimensional overlap between a response andthe following effect, the anticipatory process will be facilitated byautomatic priming of the action in a way similar to SRC (see, e.g.,Kornblum, Hasbroucq, & Osman, 1990; Proctor & Wang, 1997),which results in R–E compatibility. In Kunde’s (2001b) Experi-ment 1, participants made four different aligned keypresses to fourdifferently colored circles. For the corresponding R–E mappingcondition, the horizontally aligned box on a monitor compatiblewith the location of the response was filled with a white color asan effect. For noncorresponding R–E mapping, the adjacent boxwas filled with white, which was not compatible with the responselocation. R–E mapping condition was fixed within blocks of trials,so that participants could reliably predict the spatial responseeffect within each block. RT was 21 ms shorter for the correspond-ing condition than for the noncorresponding condition. Kundereported that the endogenous activation is time consuming, findinga larger R–E compatibility effect for the longer RTs in a distribu-tion.

R–E compatibility has been shown to be replicable in many taskvariations (e.g., Kunde et al., 2004). For instance, R–E compati-bility has been applied to nonspatial dimensions of R–E mapping.Responses were facilitated when the intensity of the keypressescorresponded to the loudness of the tone effect (Kunde, 2001b,Experiment 2). An R–E mapping effect was found in the temporaldomain as well: RT was facilitated when short-duration keypresseswere followed by short tones and long-duration keypresses by longtones (Kunde, 2003). Other domains of mapping, such as color-naming response and visual color effect (either color name orcolored color name; Koch & Kunde, 2002) and typing responseand corresponding letter effect (Rieger, 2007), showed significantR–E compatibility effects of 10 ms to 80 ms.

Koch and Kunde (2002) extended Kunde’s (2001b) R–E com-patibility idea to the abstract property of R–E relation. They testedwhether the response also could be facilitated by a conceptuallyshared effect. Participants said color-word names (blue, yellow,green, or pink) in response to arbitrarily mapped visual digits (1, 2,3, or 4). The action effects were colored color words (e.g., greenwritten in green), colored Xs (XXXX in green), or a white-coloredword (for Experiment 2). Results showed an R–E effect of 80 msbetween compatible and incompatible mapping. When the R–Eeffect was compared across effect-type conditions, the largest R–Eeffect was found for the colored-color word condition, with anintermediate R–E effect for the color-word condition and the leastR–E effect for colored Xs condition. The authors concluded thatresponses can be facilitated by mutual priming of verbal andphysical properties of the effect.

In their Experiment 2, Kunde et al. (2004) explored the questionof whether the action effect influenced an early process of actioncontrol (selection) or a later process (initiation). On two thirds ofthe trials, a valid color cue preceded the target by randomly variedstimulus onset asynchronies (SOAs), indicating the next response.For the remaining trials, a neutral cue was presented. The R–Ecompatibility effect was still evident when the action was cuedsufficiently far in advance to allow selection to be completed. Ifthe action effect mediates only the selection process, the R–E

compatibility effect should have been eliminated at long SOAs.Thus, Kunde et al. suggested that response selection and initiationare not independent but are different phases of a single process foractivation of anticipatory effect codes. If the action–effect condi-tion mediates the selection process at all, the R–E compatibilityeffect should at least be reduced at long SOAs. However, resultsshowed a constant effect size, suggesting that the effect conditiononly affects the initiation process.

The authors of the studies reported pronounced learning im-provement by a natural R–E mapping. The issue of whether aparticipant can selectively attend more to the natural mapping ofR–E than to an arbitrarily offered mapping was raised by Hommel(1993). He showed that the performance of R–E mapping can bereversed by a task instruction; thus, the compatible R–E mappingwas not always superior to the incompatible mapping. Participantswere required to make spatial keypresses to different pitch tonespresented to the left or right, and a contingent light flash on theopposite side followed the response. For one condition, partici-pants were told to press left and right keys to the tones; for anothercondition, they were told to produce left and right light onsets. Inthe latter case, the Simon effect reversed to favor noncorrespond-ing keypresses. This finding reveals that the activation of theaction code is dependent on the actor’s goals and that the processis intentional rather than spontaneous. Wang, Proctor, and Pick(2007) also found that the Simon effect was eliminated when apostresponse cursor movement was opposite to the direction of thehand movement of a participant using a wheel control. Evidencesuggested that some participants encoded their actions in terms ofcursor movements, whereas others coded their actions relative tothe hand movements. Wang et al. concluded that the cursor move-ment provided an alternative option for coding the actions.

Action Effect in Animal Learning: DifferentialOutcome Paradigm

Though the experimental paradigm of manipulation of S–R–Etriplets is relatively new in human learning, researchers in animallearning studies have used this paradigm to test differential out-come effects for many years (e.g., Rescorla & Colwill, 1989). Theprocedure of the differential outcome task paradigm is comparableto the simple version of a CRT task used to measure primingeffects of sensorial feedback. Two discriminative stimuli, S1 andS2, which signal contingent responses, R1 and R2, are presented.When each response brings different outcomes, O1 and O2, respec-tively, the discrimination learning is typically completed fasterthan when the responses are reinforced by the same outcomes (e.g.,DeLong & Wasserman, 1981; Fedorchak & Bolles, 1986).

Meck (1985) conducted a study using two-phase procedures oftraining and testing,5 as in action–effect studies. For training, ratswere conditioned to press a left or right lever for each trial. No cue

5 Meck (1985) used three procedure phases: pretraining, postreinforce-ment signal training, and prereinforcement signal training. The pretrainingphase was to adjust rats to the box environment and the lever-pressingtasks. Postreinforcement and prereinforcement signal training were similarto the two-phase procedure devised by Elsner and Hommel (2001). Toavoid confusion, we refer to the postreinforcement signal training phase asthe training phase and the prereinforcement signal training as the testphase here.

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was provided to indicate which lever was to be pressed. The leverto be considered correct was determined randomly on each trial,with the probability of each lever being correct set at 50%. Eachcorrect response was reinforced with a food pellet that was ac-companied by a redundant noise signal. For instance, a 2-s noisesignal was given for a right response and an 8-s noise signal for aleft response for one group. After performing this discriminationtask in the training phase, the rats received a test phase in whichthey were to learn a new relation between tone and the spatial leverpressing. The short or long noise signals were provided as indica-tors of the correct lever to be pressed. The rats performed this newdiscrimination task better when the relation between the press andthe tone was consistent with the prior task than when it was thereverse. Meck concluded that the rats formed a bidirectional as-sociation between a particular lever press and a postreinforcementsignal. He suggested that rats may associate two events that occurwithin a brief time period as an adaptive way to predict eitherevent.

Historically, the role of reinforcer or action outcome in animallearning was treated as “stamping in” an association betweenstimulus and response. According to the law of effect (Thorndike,1905), the S–R association was solely responsible for the occur-rence of the instrumental response, and learning of the reinforcer(O) or the relation between the response and the reinforcingoutcome (R–O) was not a theoretical interest. However, Spence(1956) suggested that instrumental learning consists of two factors,Thorndikian S–R association and reward expectancy from a stim-ulus by S–O association.

According to modern two-process theory (Rescorla & Solomon,1967), the stimulus (S) in the presence of which the instrumentalresponse is reinforced is associated with the response outcome (O)through Pavlovian conditioning. Through this S–O association, Scomes to motivate the instrumental behavior by activation of acentral emotional state. This “expectancy” is reinforced also byE–R (expectancy–response) links. The nature of the emotionalstate or motivation will depend on the nature of the reinforcer,which is what Mowrer (1960) more generally called hope. Howcould hope or some other Pavlovian expectancy motivate instru-mental behavior? Rescorla and Solomon (1967) pointed out that ifa Pavlovian expectancy motivates instrumental behavior, then thepresentation of a Pavlovian conditional stimulus should alter thecourse of instrumentally reinforced responding. Thus, the rate ofan instrumental response will be modulated by the presentation ofa classically conditioned reinforcer.

The differential outcome paradigm in animal learning revealsthat the reinforcer (O) is an active participant in integration of theinstrumental association. Colwill and Rescorla (1985, 1986, 1990)found that instrumental behavior results from the formation of anassociation between a response (R) and its contingent outcome(O). They used a devaluation of outcome procedure to show thatthe responses are differentially associated with the outcome.Outcome-specific learning implies the presence of associationsbetween responses and outcomes. Rescorla (1991) also suggestedthat the strength of an association between R and O can bemodulated by selectively pairing the response with the same out-come or a different outcome in the test phase. Each stimulusactivates a unique representation of outcome and finally inducesthe appropriate response. This bidirectional R–O association issupposed to be a motivator of the differential outcome effect.

Trapold and Overmier (1972) accounted for the effect in a similarmanner. According to them, the co-occurrence of S1 and O1 or S2

and O2 makes unique associations between them. These differen-tial outcomes permit participants to anticipate differently for eachstimulus, E1 or E2. The distinctive anticipation to each stimulusalso plays a discriminative cue to initiate an action. Thus, discrim-ination learning involves both the exogenous cue of S and endog-enous activation of E. In the respect that a different anticipation isconditioned to each response, this account is strikingly close to theideomotor principle in human behavior.

Though Hommel (1996) pointed out that the Thorndikian for-mulation of instrumental behavior is considerably different fromthe action–effect model in human behavior, some formulationsmore analogous to the ideomotor principle can be found in modernanimal models (e.g., Trapold & Overmier, 1972). BidirectionalR–O association assumption and the modulation of the responsepattern by the outcome condition are similar to the ideomotorprinciple in the sense that only an R–O association is required tocarry out an intended behavior.

Stimulus-Driven Action

In this section, we offer varied examples of action controlmodulation by environmental cues. A perceiver can detect a dy-namic action feature inherent in a static display or comprehendanother person’s action by mirroring that action in her or hisrepresentation of action production. Mere observation of dynamicaction also affects the control of action. Responses can be activatedintentionally or automatically by exogenous events. Contrary tothe action–effect studies described previously, the studies de-scribed in this section did not offer an arbitrary action effect suchas a tone or visual stimulus. Otherwise, the studies demonstratedthat an action is facilitated by a display pattern that is similar to theconsequent feedback of the action.

Ideomotor Compatibility

Greenwald (1970) suggested that presentation of a stimulus thatresembles the following action’s sensory feedback can activate theaction itself; thus, the selection process is bypassed. Even withoutthe acquisition stage of relating actions to outcomes (Stage 1), avery special stimulus can prompt an action. Put another way, it canbe assumed that Stage 1 is completed already as a consequence ofexperiencing the environment during an observer’s past. Thus, thegeneration of the anticipatory image for its perceptual consequenceis a necessary and sufficient process to initiate the intended action.If the stimulus exactly corresponds to the perceptual image of theaction outcome, the response code does not need to be regenerated;thus, the time to select the required response code is reduced.

In this sense, Greenwald proposed that the ideomotor principlecan contribute to the phenomena of SRC (for review, see Proctor& Vu, 2006). Greenwald (1970) suggested,

S–R compatibility facilitates response selection by minimizing thetime required for access to an image of the correct response. Thisargument especially merits consideration in explaining effects ofcompatibility produced by spatial mapping of response onto stimuli,since, in these cases, it seems unwarranted to claim that highlypracticed relations are involved. (p. 91)


Prinz (1997) and Beckers et al. (2002) also suggested that SRCis the phenomenon that is most closely related to the commoncoding system. If one of the properties of the response is congruentto a property of the stimulus physically or conceptually, respond-ing to that stimulus is facilitated more than when the relationbetween a stimulus and a response is not congruent.

Greenwald (1972) introduced the term ideomotor (IM) compat-ibility for S–R relations in which a stimulus closely resembles thesensory feedback from the required response. For example, saying“a” to the auditory sound “a” is typically categorized as an IM-compatible task. This concept is also partly echoed by later re-searchers who advocated the common coding hypothesis. Forexample, Hommel et al. (2001) claimed that a person can activatethe action code when he or she perceives an event that resemblesthe to-be-performed action effect.

However, the boundary of the IM-compatibility concept is notsettled. IM compatibility has been treated as an absolutely differentquality from SRC in some literature (e.g., ten Hoopen et al., 1982),but occasionally it has been defined as a special case of SRC thatis due to similar factors as other SRC effects. For example,Greenwald (1972) identified IM compatibility as an extreme endof the compatibility continuum. He applied the term low IMcompatible to describe a task requiring participants to make left orright manual movements to the auditory stimuli “left” or “right” incontrast with the term high IM compatible applied to describe atask requiring participants to repeat the vocal responses “left” and“right” to the auditory stimuli “left” or “right.” Greenwald (2003)also claimed later that even an IM-compatible task still requires acost-consuming selection process if the level of preactivation forthe action code is subthreshold. However, if preparation of theaction code is largely complete, the presentation of the stimulustriggers the action without an extra cost of response selection. Thistype of ideomotor approach, which describes IM compatibility asan extreme form of SRC, is called a weak version of IM compat-ibility (Koch & Kunde, 2002). But Greenwald also put forward astrong version of the ideomotor mechanism (Greenwald, 1970;Greenwald & Shulman, 1973), in which IM compatibility is re-garded as a unique concept from typical SRC. An IM-compatibletask does not require transformation of the stimulus codes to theto-be-performed actions because action is encoded in terms of itsanticipatory feedback. Thus, any signals that closely resemble thefeedback will activate the corresponding response code directly.

Greenwald and Shulman (1973) had participants perform twoIM-compatible tasks in a dual-task setting. Task 1 (T1) required aleft–right joystick movement corresponding to the left or rightdirection in which an arrow pointed, and Task 2 (T2) requiredvocalization of “a” or “b” corresponding to the name of a spokenletter. The SOA between the stimuli for T1 and T2 was varied.Typically, when the SOA is short, the T2 performance is moredisrupted than when the SOA is long or when two tasks areperformed alone (e.g., Pashler, 1994). This phenomenon, calledthe psychological refractory period (PRP) effect, is often attributedto a response–selection bottleneck. Greenwald and Shulman ex-pected that the PRP effect would be eliminated when both taskswere IM-compatible and did not require response selection. TheirExperiment 2 showed no PRP effect, leading them to conclude thatthe limited-capacity translation process from stimulus to responseis bypassed for IM-compatible tasks.

However, several other researchers have not found perfect timesharing with two IM-compatible tasks (e.g., Lien, McCann, Ruth-ruff, & Proctor, 2005; Lien, Proctor, & Allen, 2002; Lien, Proctor,& Ruthruff, 2003; Shin, Cho, Lien, & Proctor, 2007). Also, it isunclear why one IM-compatible task paired with a non-IM-compatible task would produce impairment in participants who areperforming the two tasks at the same time if an IM-compatible taskdoes not require any selection process. Shin and Proctor (2008)suggested that the operational use of IM-compatible tasks in pre-vious studies was not adequate to assess strong IM compatibilityand showed that the visual–manual tasks did not activate an actioncode completely and automatically. CRT tasks usually show anincreasing pattern of RT as a function of the number of S–Ralternatives (Hick, 1952), which is attributed mainly to an increasein response-selection difficulty (e.g., Usher, Olami, & McClelland,2002). Shin and Proctor (2008) varied the number of S–R alter-natives (two or four) for a visual–manual task paired with atwo-choice auditory–vocal task in the PRP paradigm. RT waslonger with four visual choices than with two, and this lengtheningof RT for the four-choice task increased the size of PRP effect forthe auditory–vocal task. The results demonstrate that the visual–manual task still requires limited-capacity response-selection pro-cesses and is not IM compatible in the strong sense.

IM-compatible setting of a visual-manual task. Researchershave made several attempts to provide a body-related gesture as astimulus and then investigate the execution of the correspondingaction. Brass, Bekkering, Wohlschlager, and Prinz (2000) sug-gested that observing hand action evokes a corresponding responseto some degree. They required participants to make an index-fingermovement, either lifting or tapping, in response to a go signal,which was a lifting or tapping hand gesture. In one trial block, aparticipant lifted his index finger to the go signal, as in a simplereaction task. Brass and his colleagues used dynamic images offinger movements for a go signal, which were either lifting ortapping movements of index finger. The two go signals occurred atrandom in one block. When an upward moving finger signaledparticipants to initiate a lifting movement, the response was sig-nificantly faster than when a downward moving finger did. TheS–R compatibility effect was larger for slower mean RT quintiles,implying that the process would be time consuming.

Brass et al. (2000) suspected that the effect might have resultedfrom spatial direction of a go-signal image rather than beingtriggered by similar action of the finger movement. Thus, theyadded another condition, which provided a moving object for a gosignal. To achieve identical movements of object and hand, theydigitally recorded a black square marked on a finger engaged inlifting or tapping and then erased all but the black square from thepicture. Hence, the objects moved upward or downward withoutmeaningful human gestures of lifting or tapping. A more pro-nounced SRC effect was found for the hand gestures than for themoving object condition. Brass et al. noted that the SRC effectcame from two types of mechanisms, movement direction (up-ward/downward) and movement type (lifting/tapping). When thetwo types of compatibility are achieved in one stimulus conjointly,as is the case for observation of finger movements, performancecan be more easily facilitated than if only one source of informa-tion is available, as for moving objects. The facilitation frommovement direction (upward/downward) compatibility existed forfast and slow responses, suggesting that processing of spatial

961IDEOMOTOR THEORY

direction was simple and built up at an early stage. However, theSRC effect for finger movement (lifting/tapping) observation in-creased as RT increased. Consequently, Brass et al. proposed thatthe processing of finger movements is more complex and timeconsuming for effectively initiating action.

Brass et al. (2000) conducted another experiment, using flippedhand gestures as go signals to separate the movement type anddirection from finger movement picture. For a flipped picture, theexperimenters achieved the upward direction of finger movementby tapping gestures and the downward direction of finger move-ment by lifting gestures, which were opposite to the normal pic-ture. Therefore, if the compatibility effects of their Experiments 1and 2 were primarily caused by the directional component of thefinger images, the compatibility effect should have been presentonly when the direction of the finger image corresponded with theaction direction. The results showed that initiation of lifting ortapping movements was facilitated when the same body gestureswere offered even with the opposite direction of movement,though the size of the effect was smaller than with an unflipped gosignal. Brass et al. concluded that an ideomotor kind of S–Rarrangement was realized through the use of simulated real actionfor a go signal, and they posited that this arrangement is closer toGreenwald’s notion of IM compatibility. Two sources of facilita-tion mechanism, from movement type and direction, were exe-cuted simultaneously. When the required performance was a sim-ilar action with same effector, the body-related gesture primarilyaffected the corresponding action.

Other authors (e.g., Hommel & Lippa, 1995) have assumed thattwo different reference systems are processed to represent thespatial dimension. Klatzky (1998) distinguished an egocentricreference frame, in which locations are represented relative to theperceiver’s perspective, from an allocentric reference frame, inwhich locations are represented relative to an external referentobject. Analogous to these reference systems, there may be twodifferent mechanisms to represent a human’s body movementdirection. The egocentric system processes the spatial informationgiven by others’ body movements with respect to the movementsgenerated by the self. The allocentric system can process the sameinformation in terms of changes of position in the environment.When an individual observes others’ body movements, one infor-mation source from the egocentric system (e.g., lifting or tapping)and another from the allocentric system (e.g., downward or upwarddirection) may be processed simultaneously.

As shown by Brass, Bekkering, and Prinz (2001), the egocentricinformation is primarily used when the stimulus is a human-body-related movement and the response requires similar movement. Adynamic visual stimulus of moving the index finger was verysimilar to the required action of moving the index finger in therespect to body topology. Thus, this task required the same refer-ence system for perception and action, and the stimulus almostperfectly matched the representation of the action that the partic-ipant intended to perform. A biological motion picture might bringabout the corresponding action code more automatically than aspatial feature in the object stimulus, since a picture containing liftor tap movement shares more common features than a simplespatial cue. Sturmer, Aschersleben, and Prinz (2000) also reportedthat observing a task-irrelevant stimulus of grasping or spreadinggestures of hand can facilitate corresponding grasping or spreadingaction in a Simon-like task. However, Jansson, Wilson, Williams,

and Mon-Williams (2007) criticized the methods used by Brass etal., since their biological stimulus was more salient than the objectmotion of a dot. When Jansson et al. manipulated the objectmotion as a pen tapping/lifting scene and compared the perfor-mance with a finger tapping/lifting scene, they did not observe thestimulus type effect or any interaction with the stimulus type. Intheir other subsequent experiments, they did not find any perfor-mance difference for responses to the biological motion or biolog-ically generated motion compared with responses to the objectmotion.

Body-related spatial information does not always automaticallyfacilitate a corresponding action. Ottoboni, Tessari, Cubeli, andUmilta (2005) reported that a handedness picture (see Figure 7) didnot produce a Simon effect. However, if a hand picture wasprovided with forearm extension (see Figure 8), a Simon effectwas found. A regular Simon effect was obtained for the back view,and a reverse effect was obtained for the palm view. Ottoboni et al.concluded that what is automatically coded in the hand stimulus is“sidedness,” not “handedness.” In their experiments, participantsmade keypresses with the two index fingers; thus, their handpositions corresponded to the back view. When the hand viewswere presented without extension of the forearm, the views of theback of the left hand and the palm of right hand looked similar (seeFigure 7). This could cause participants to ignore any meaningfulinformation from the two pictures or a reverse effect from palmview could cancel out some inherent facilitation from a corre-sponding back view display. For the handedness picture withextension of forearm, the sidedness cue was provided by the jointangle of hand and forearm. A participant could process this clearinformation automatically, no matter which handedness is shownin the picture.

Regardless, the results from Ottoboni et al. (2005) seem tocontradict those of Brass et al. (2001), who found that a body-related motion picture facilitated the same action even when thedirection of movement in the picture was opposite to the requiredhand action. If a body-related visual stimulus automatically acti-vates corresponding movements, Ottoboni et al. should have foundfacilitation from the palm view version of the hand picture, butthey did not. However, the participants’ task in their study was tomake a left or right keypress to the color of dots, and the handpicture was irrelevant; this task is in contrast to Brass et al.’s taskin which participants were required to perform an action identical

Figure 7. Hand stimuli. Reprinted from “Is Handedness RecognitionAutomatic? A Study Using a Simon-Like Paradigm,” by G. Ottoboni, A.Tessari, R. Cubeli, and C. Umilta, 2005, Journal of Experimental Psychol-ogy: Human Perception and Performance, 31, p. 782. Copyright 2005 bythe American Psychological Association.


to the go-signal picture. Some researchers have found that animage of one’s body parts needs to be rotated for participants toidentify the side of the body to which a disoriented body partbelongs (e.g., Parsons, 1987; Sekiyama, 1982). Thus, a participantfrom Ottoboni et al.’s task should have tried a mental rotation toidentify the handedness of the picture, especially for a palm viewto match the participant’s current hand position, which from theparticipant’s perspective was a back view. Participants might givemore attention to the clear spatial cue such as the angle of theforearm rather than attending to the handedness cue, which maytake longer time to identify it.

Other examples of IM compatibility. In a CRT task, differ-ent reference frames typically are used for perceiving and acting.For example, in a standard task with visual stimuli and keypressresponses, perception for stimuli on a vertically oriented monitoroccurs in the vertical plane, and action occurs with keys on thehorizontal plane. A participant must parse the spatial componentsof the visual display and transform the resulting spatial represen-tation into the spatial property of the to-be-performed action.However, aimed movements such as saccades, pointing, catching,or grasping occur within the same physical reference system asthat for perception. In terms of low-level processing, aimed move-ments may also require a separate spatial reference system. Withregard to kinesthesia, an agent is to perform a one-to-one trans-formation from an object identification in a given visual display toa motor pattern to be performed. However, the aimed movement issupposed to share a common spatial reference with perception ofthe visual display in regard to a high-level, modality-free repre-sentational structure. According to the ideomotor principle, anaction is assumed to be represented by its goal state. Thus, plan-ning of movement in terms of kinesthetic force is not an ideomotorissue, and trajectory processing of the aimed movement is not acrucial parameter, but the final position of the action is.6 Thus,when displays and controls are eventually overlapped in the samephysical location, a participant does not need to parse the spatialproperty to transform perception to action.

Several researchers who have attempted to realize IM compat-ibility have used a physically common reference system for dis-plays and controls. Wright, Marino, Belovsky, and Chubb (2007)

reported that RT is independent of the number of S–R alternatives,provided that the S–R mapping is maximally compatible andselection of the effector is predetermined, as in a pointing task.7

Participants making aimed movements to the target did not exhibitprolonged RT when the number of alternative targets was in-creased. Ten Hoopen et al. (1982) concluded that IM compatibilitymay depend on a high degree of perceptual similarity betweenstimuli and responses. In their study, the number of alternativeseffect disappeared only when vibratory stimuli were presented tothe effectors with high frequency and amplitude. They consideredonly the vibrations that stimulated the same receptors as thosestimulated by pressing a response key to be truly IM compatible.It is noteworthy that for the tasks described by Wright et al. and tenHoopen et al., the same reference system was used for perceptionand action.

Ideomotor Action

When a person observes other people’s rapid and intense ac-tions, her or his body tends to move involuntarily or even counter-voluntarily. For example, when viewing a golfer missing a putt, theviewer’s body tends to lean in a certain direction. As a narrowlydefined term, the concept of ideomotor action was introduced as anaction that tends to arise from watching another’s performance(Carpenter, 1874; Prinz, 1987). Ideomotor action can be classifiedinto two categories, perceptually and intentionally induced actions(De Maeght & Prinz, 2004; Knuf et al., 2001; Prinz, 1987).

Knuf et al. (2001) considered perceptually induced ideomotoraction to be movement that carries on the inherent inducing powerin the perceptual representation of the scene, with an observertending to perform movements that would lead to the continuingmotion. Thus, the example of an observer of a missed putt tendingto lean in the direction of the golf ball’s trajectory falls in thiscategory. The other category of ideomotor action is intentionallyinduced movement, in which an observer acts in an intentional wayto seemingly affect the action in a perceived scene. For example,an observer of a missed putt tends to move his or her limbsinvoluntarily in the direction of the desired goal, as if trying tochange the direction of the ball. Knuf et al. termed this action as anidle-running instrumental act, since the action cannot be instru-mental at all.

To identify which ideomotor action is primarily used in invol-untary action during observation of movement scene, Knuf et al.(2001) used tasks that were similar to playing billiards and bowl-ing. In the task similar to billiards-playing in their Experiment 1,a participant was able to see a ball approaching a target, which theball either hit or missed. The participant was told to perform anintervening action to make hitting the target with a ball moreprobable. In the ball-control condition, the participant hit the ball

6 Rosenbaum et al. (1990) demonstrated that voluntary movement isgoal driven by citing ideomotor theory. They suggested that action plan-ning is modulated by minimization of conflict in the end-state posture.Participants grasped an object with initial awkwardness of posture to allowa final comfortable posture.

7 But several other investigators also have reported that a pointing taskwas affected by degree of choice (e.g., Lamb & Kaufman, 1965). Theineffectiveness of a number of alternatives seems to be restricted to limitedstimulus–response arrangements, even for a pointing task.

Figure 8. Hand stimuli with extended forearms. Reprinted from “IsHandedness Recognition Automatic? A Study Using a Simon-Like Para-digm,” by G. Ottoboni, A. Tessari, R. Cubeli, and C. Umilta, 2005, Journalof Experimental Psychology: Human Perception and Performance, 31, p.782. Copyright 2005 by the American Psychological Association.

963IDEOMOTOR THEORY

using a cue controlled by the joystick, and the ball was to hit theright cushion first and then the top cushion before finally hittingthe target. In the target-control condition, the participant was tomove the target horizontally to increase the chance of it being hit,but this intervening action was to be completed before the ball hitthe top cushion (Figure 9).

Knuf et al.’s (2001) Experiment 1 revealed intentionally inducedmovement in the target-control condition. Participants attempted toshift the target toward the ball even after the ball bounced off thetop cushion, thus the instrumental action was not effective at all.However, this intentionally induced movement was not found inthe ball-control condition, and perceptually induced movementwas not observed in any condition. Knuf et al. found that theinstrumental action seemed to be continuously effective for thetarget-control condition, but the intervening action of the ball-controlled condition was quite temporary, effective only when thecue hit the ball in the first scene. In Experiments 2 and 3, Knuf etal. employed a bowling game. Instrumental movements by handsand noninstrumental movements by feet and hands were measuredon each trial. Results showed that participants made systematichand shifts to increase hit rate. These induced movements werecarried out to control the ball in the ball condition and the target inthe target condition. Evidence of perceptually induced movementwas fairly weak for hand movements. For head and foot move-ments, both perceptual and intentional inducements were found,and intentional induction was guided by the ball trajectory for bothconditions. The authors suggested that noninstrumental move-ments were mainly controlled by the most dynamic component inthe perceived scene, the ball’s movement. In conclusion, Knuf etal. contrasted two ideomotor action principles. Perceptually in-duced movements are guided by overlapped features between theperceivable event and the to-be-programmed action. Intentional

induction relies on the overlapped feature between goal represen-tation and action.

De Maeght and Prinz (2004) extended Knuf et al.’s (2001) studyto observation of others’ actions so that the task allowed assess-ment of ideomotor action in passive observer mode. By limitingthe active role of the player in the task, they also preventedintentional inertia, in which initial intention is maintained after theaction is completed. They designed two combined events in onetask. One was a bowling-like task, similar to that in Knuf et al.’sstudy, and the other was a traveling-ball-tracking task. For thebowling-like task (player mode), the participant was to intervene inthe action of a ball hitting a target by moving either the ball (ballcondition) or the target (target condition) via a joystick. After theinstrumental maneuver, participants were required to track a trav-eling ball vertically using a joystick while observing an allegedplayer perform bowling (observer mode). Though participants wererequired to move the joystick vertically along with the vertical posi-tion of the ball, the interest in measurement was the horizontaldimension, specifically the pattern of the offset from the center lineproduced by hand movements. If action induction occurs when aparticipant perceives a dynamic bowling scene performed by analleged player, then systematic drift should appear in the horizontaldimension.

Results showed that, for the observer mode, strong perceptualinduction was reported for both effectors. When a participant wasnot allowed to experience player mode and was instructed toperform the tracking task later (pure observer mode), both effec-tors exhibited perceptual induction. Intentional induction was ex-hibited only in the ball condition and only for the hand effector. DeMaeght and Prinz’s study is in agreement with Knuf et al.’s (2001)study in showing that the strong intentional induction from instru-mental and noninstrumental effectors always seemed to be cap-tured by the dynamic property in the perceivable scene (balltrajectory).

Imitation

Prinz (1987) included imitation of others’ movements in thecategory of ideomotor action. However, imitation itself includesmuch broader research topics than ideomotor action. Review ofmost imitation-related studies is out of the scope of this article (fora review, see Meltzoff & Prinz, 2002), but several interestingresults about imitation will be described. Among those is that even1-day-old infants can imitate buccal and manual gestures of anadult actor (Meltzoff & Moore, 1977), suggesting that the ability toimitate is innate.

To account for imitative behavior, researchers have proposedtwo complementary models. One approach is the direct mappingview, which assumes a supramodal representational system forperception features and action features. TEC (Hommel et al.,2001), active intermodal mapping theory (Meltzoff & Moore,1977), and mirror neuron accounts (Buxbaum, Kyle, & Menon,2005) are typical examples of the direct mapping hypothesis.Perceiving or imitating human body action is known to be specialbecause of its unique neurological pattern (e.g., Iacoboni et al.,2005), though the localization of brain functioning is still unsettled(e.g., Bekkering, Brass, Woschina, & Jacobs, 2005). Some re-searchers have found that neurons in the ventral premotor cortex(area F5) in monkeys, now called mirror neurons, are involved in

Figure 9. Paradigm developed to study ideomotor movements (Experi-ment 1). The task was either to drive the ball on a suitable course by thecue (so that it could hit the target) or to shift the target to the left or the right(so that it could be hit by the ball). During the induction phase (larger dots),joystick movements were ineffective (i.e., noninstrumental) in both taskconditions. Reprinted from “An Analysis of Ideomotor Action,” by L.Knuf, G. Aschersleben, and W. Prinz, 2001, Journal of ExperimentalPsychology: General, 130, p. 781. Copyright 2001 by the AmericanPsychological Association.


action comprehension and imitative behavior (e.g., Rizzolatti,2005; Rizzolatti, Fadiga, Galleses, & Fogassi, 1996). These neu-rons were reported to be activated not only from the execution ofthe action but also from the observation of the same action byothers.

Though the mirror neuron system provides a basis for overlapbetween perceived and executed motor events, some investigatorshave suggested that an extra cognitive analysis should mediate tofulfill imitation. Several analyses of intelligent errors of imitationby children demonstrated that for a complex imitation task, chil-dren must reconstruct a goal by decomposing a perceived eventinto different aspects (e.g., Bekkering, Wohlschlager, & Gattis,2000; Meltzoff & Moore, 1997). Preschool children were reportedto make more contralateral than ipsilateral errors (e.g., touchingthe left ear with the right hand more than with the left hand) whenduplicating another’s action (Bekkering et al., 2000). Contralateralerrors were reduced when bimanual gestures were required (e.g.,touching both ears using both hands by crossing the midline). Thisresult suggests that the children coded the end point as the goal ofthe imitation, and thus their task description was “touch the leftear.” The goal-directed coding strategy would yield contralateralerrors more frequently. In Experiment 2, Bekkering et al. reducedthe competing goals for contralateral duplication by requiringchildren to touch only the ear on one side with either the left orright hand to duplicate the action. This method significantly re-duced the contralateral errors. Bekkering et al. posited that chil-dren decompose a task into subgoals such as an object, an agent,and a movement path. One dominant goal over other goals wouldcapture the imitative action. This goal hierarchy guides the medi-ation between perception and action. From an evolutionary view,this error is often called an intelligent error, since flexible imita-tion brings about more critical learning than does copying anoth-er’s action exactly. Thus, one does not copy others’ actions phys-ically but imitates their goals by parsing the events.

Modulation of Perception by Action

The ideomotor principle has given more attention to the phe-nomena for influence of perception on concurrent action planningor execution. Borrowing Prinz’s (1997) term, most researchers ofideomotor theory have sought to discover “the traces of perceptionin action” (p. 133). If the ideomotor principle assumes commonrepresentation of action and perception as well as a bidirectionalinfluence between them, the model should also take into accounthow the properties of action impact perception. Several investiga-tors recently have attempted to show this opposite direction ofinfluence, that is, how planning and execution of action influencesperceptual encoding (e.g., Witt, Proffitt, & Epstein, 2005). Thisphenomenon is sometimes called perceptual resonance (Schutz-Bosbach & Prinz, 2007). Some researchers inspired by the eco-logical approach have offered a number of reports about impacts ofaction on perception (e.g., Witt et al., 2005). Concurrent or pre-planned action influences perceptual sensitivity, either increasingor decreasing it, or perceptual bias, through either overestimationor underestimation.

Contrast

Perceptual contrast refers to disruption of the perceptual pro-cess, or perceptual bias in a direction opposite to that of the

planned or concurrent action. Musseler and Hommel (1997a;1997b) found an inverted SRC effect, for which stimulus identi-fication was disrupted more when a to-be-executed response wascompatible with a masked visual arrow than when it was incom-patible. They called this temporary insensitivity to the stimulusaction-induced blindness. In their task, a participant was to per-form a sequence of keypresses for two arrows (S1 and S2) pre-sented across time. The unmasked S1 was a precue that did notrequire an immediate response. Participants were then to make anobligatory double keypress (R0) after a fixed delay from S1, andthis R0 triggered the presentation of S2, which was provided forindividually customized durations ranging from 14 ms to 70 msbefore being masked. A compatible left or right keypress (R1) to S1

was to be made as quickly as possible after S2 appeared. Anunspeeded judgment (R2) of arrow direction for S2 (the maskedstimulus) was to be completed after a delay of at least 1 s fromcompletion of R1. Participants were less accurate at identifying thedirection of S2 when R1 corresponded to S2 than when it did not.Furthermore, the interval between R0 and R1 was longer when themasked S2 was compatible to R1. Musseler and Hommel explainedthese somewhat counterintuitive results by the common codingassumption: Participants became momentarily less sensitive to aparticular stimulus that shared features with the action. Blindnessto response-compatible stimuli has also been observed in otherstudies with a similar sequential keypress procedure (see Kunde &Wuhr, 2004; Wuhr & Musseler, 2002).

In line with this approach, Schubo, Prinz, and Aschersleben(2004) found that ongoing movement execution affected a simul-taneous perceivable event. Participants performed a sinusoidaldrawing task while observing sinusoidal movement of a dot alongan invisible trajectory for 2 s. Participants copied the motion andshape of the preceding trial’s stimulus and were to memorize thecurrent stimulus’s motion and shape for the next trial’s drawing,which was termed a serial overlapping response task. A new trialwas initiated after an intertrial interval (ITI) of 2–8 s. Amplitudeand velocity of the drawings were measured. The drawing move-ment was slower and smaller when large and fast stimulus motionwas presented concurrently, and vice versa. Hence, reverse SRCeffects were discovered when a stimulus and response for one trialwere temporally separated. Schubö et al. concluded that it becomesprogressively more difficult to distinguish two functionally unre-lated events as more features are shared between the currentmovement and the perceivable event. This contrast pattern waspreserved when a trajectory of traveling dots was kept visible onthe display. Schubö et al. argued that an action code shares manyfeatures with the stimulus code, and a conscious endeavor isrequired to inhibit automatic activation of the action code thatoccurs as a consequence of perceiving the current stimulus. Theyalso found that the contrast effect was pronounced only for theshortest ITI (2 s) and disappeared after a few seconds. For thelongest ITI (8 s), it was replaced by an assimilation pattern.

Contrast also refers to perceptual bias that is distorted in anopposite manner of the concurrent action planning. Viswanathan,Tobin, Fowler, and Magnuson (2008) observed that participantsless often categorized a certain sound as /ba/ when they were tomake a silent “kiss-like gesture” similar to the lip movements topronounce the /ba/ sound. This contrast effect was observed whenthe silent lip gesture preceded the sound presentation by 500 msand disappeared when participants were required to make the

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gesture at the same time as the sound. Hamilton, Wolpert, andFrith (2004) required participants to lift a box of various weightswhile observing a movie of another person lifting a box. Partici-pants overestimated the weight of the box lifted by the actor whenthe box that they lifted concurrently was relatively light andunderestimated it when the box they lifted was heavy.

Assimilation

Perceptual assimilation refers to enhancement of detection oridentification of the stimulus, or perceptual bias in the samedirection as the action. Craighero, Fadiga, Rizzolatti, and Umilta(1999) found that preparation for grasping an object facilitateddetection or discrimination of the change of the object alignmentwhen the features of the to-be-performed action and the targetobject matched. This effect disappeared in the case in whichidentity or orientation of the visual objects was matched, but themotor affordance (e.g., keypresses) did not correspond to theobject.

Ishimura and Shimojo (1994) discovered that participants weremore likely to judge the direction of ambiguous apparent motion asbeing the same as that of a concurrent hand movement, an effectthat they termed action capture. Wohlschlager (2000) extendedthis effect by varying the degree of correspondence between theapparent motion and the hand movement. He used circular flick-ering dots for the perceived motion stimulus. The motion direction(clockwise or counterclockwise) was judged by a left-hand key-press made concurrently with movements of the right hand. Anarrow in the center of the circular dots cued the direction of therequired hand movements. Participants varied the right-handmovements by rotating a knob (clockwise/counterclockwise forExperiment 1) or pressing a key (right/left for Experiment 2 andup/down for Experiment 3). Wohlschlager found the assimilativebias of perception for these three tasks and for a planned actiontask (Experiment 4). Witt et al. (2005) showed that participantsestimated the distance to a target to be less when they reached forthe target with a baton than when they reached without one.

The Mechanisms Underlying Contrast andAssimilation

It has usually been argued that phenomena of assimilation andcontrast result from common cognitive codes. One of the accountsfocuses on the temporary limitation of the attentional resource toprocess the same features for two different functions. According toSchutz-Bosbach and Prinz (2007),

[Because] action and perception-related processes draw on identicalcognitive codes . . ., those codes that are currently “in use” for spec-ifying a response are less available for perception. Increasing the timeinterval between action production and perceptual encoding mightdissolve this competition of action and perception-related codes. (p.351)

It is noteworthy that the attentional limitation in processingcommon features has been observed often in dual-task situations(e.g., Schubo et al., 2004). Though the two tasks were describedseparately, such as action and perceptual judgment, the tasks wereessentially the same in that participants had to attend to the samespatial feature of the stimulus to select responses for each task. An

action must be performed that shares the same property of theperceived scene simultaneously with the scene being encoded.Participants may have to suppress involuntary activation from thestimulus to perform an earlier planned action successfully at thesame time. This conflict will be more severe when the intervalbetween the two events is short. In several experiments (e.g.,Schutz-Bosbach & Prinz, 2007), increasing the interval betweenthe tasks has been shown to solve the conflicts of attending to thecommon feature and produce assimilation.

When the tasks for action and perception do not require attend-ing to the same stimulus feature, the assimilative enhancement hasoften been obtained. For instance, Craighero et al. (1999) askedparticipants to hold the instrument (action) while performing adetection task (perception). The action task did not require extract-ing a perceptual feature from the stimulus to be detected, whichmeans that perceptual conflicts from the dual-task setting wouldnot be involved in this action task. Thus, assimilation or contrastmay depend on whether the perceptual feature to be processed isrelevant or irrelevant to the current action planning. Some re-searchers have proposed a similar hypothesis based on TEC. Theysuggested that contrast occurs when two or more features in theenvironment need to be integrated. But when the feature to beperceived is not relevant to the required action, as in a Simon task,the feature does not need to be integrated, and assimilation occurs(Hommel & Musseler, 2006; Musseler & Hommel, 1997a, 1997b).

Contrast and assimilation phenomena also include perceptualbias, which can be in the same or opposite direction as theconcurrent action. The boundary condition to decide the directionof the bias is whether the perceptual judgment is relevant to theconcurrent action in terms of the “actionability” or intention. Forinstance, Witt et al. (2005) asked participants to give an oralestimate of the distance from a wood handle to the target in inches.Assimilation was observed when they were required to hold thehandle, with distance underestimated. According to Witt et al., theenvironment is perceived in terms of ability to act out. Theyposited that use of a hand tool changes the perception of theimmediate space, since the object seems to be more reachable orgraspable with the tool. In contrast to assimilative bias, a contras-tive effect was often observed when perceivers were required tojudge another person’s action (Hamilton et al., 2004), which waslikely to be unrelated to the actor’s intention to act out. Influencefrom perception to action seems rather consistent, typically pro-ducing assimilation; however, the perceptual modulation whileacting produces various types of illusion or sensitivity.

Discussion

Ideomotor Theory: Strong or Weak?

Our aim in this review was to provide ample evidence ofperception–action coupling phenomena under the name of ideo-motor phenomena and to organize those cases according to theirmethodologies and the category to which they refer. We havepresented evidence from several lines of research, which are or-ganized, along with major findings, in Table 1.

The interaction between action and perception is not a surprisingnew discovery. Incorporating an anticipatory mechanism betweentwo contingent events and, later, priming one event by presentingthe other is not a unique feature of the ideomotor account either. It


has been assumed to be an essential intelligent component ofadaptive behavior in cognitive psychology, neuropsychology, an-imal learning, and artificial intelligence (Blank, Lewis, & Mar-shall, 2005; Butz, Sigaud, & Gerard, 2003; Kunde, 2001b; Rosen,1985; Schubotz & von Cramon, 2001). In the cited articles, themental representation of the intended action effects is the cause ofthe action.

However, in ideomotor theory, this phenomenon is viewed in amore radical manner than in conventional approaches; for instance,ideomotor theory suggests a common domain for action and per-ception in general or action potential preserved in perception. Wedefine a strong ideomotor theory as one that describes theperception–action interface as one that does not require any inter-mediate steps for translation between the two domains. Mostideomotor theories are strong ones, although they may suggestdifferent levels of strength in specific subhypotheses. A stronghypothesis can be divided into whether it is a general framework(Category 1), such as TEC, or a more limited account for a specificdomain, such as imitation (Category 2). A weak hypothesis sug-gests that an action should be mediated by additional cognitiveprocesses to construct a motor pattern corresponding to the idea(Category 3). In fact, a weak hypothesis may not be truly anideomotor theory, but in custom, this view has been termed a weak

ideomotor hypothesis for depiction of the relation between percep-tion and action (e.g., Jansson et al., 2007; Shin & Proctor, 2008).

As noted, TEC has often been regarded as nonfalsifiable. Hom-mel et al. (2001) acknowledged that TEC is deliberately under-specified, indicating that “TEC’s main mission at this point is tostimulate deliberations and discussions about basic principles ofperception/action architectures” (p. 914). To decide whether TECis a strong or weak hypothesis does not seem to be simple either.If a hypothesis only accounts for the early part of action, as TECdoes, it may be not eligible to be called a strong ideomotor theory.As quoted in the introduction, Hommel et al. (2001) stated thatperception in their model shares several attributes with propertiesattributed to the ventral processing stream. If TEC is based onventral processing, the system should transform the sensory inputstored in memory to an action code in additional steps. Severalideomotor-related studies relate more directly to the dorsal pro-cessing stream, which specifies an action by discovering actionpotentiation from the perceived events (e.g., Brass et al., 2000).

Ideomotor theory should take into account late action (executionof action) by an idea; in other words, it should be “strong,” inwhich case it may acquire unique status for depiction of therelation of action and perception. Otherwise, it is difficult todissociate the ideomotor hypothesis from other competing cogni-

Table 1Findings of Ideomotor Studies Organized by Direction of Modulation, Activation Type, and Task Type

Direction/activation type/task type Finding

Modulation of action by perceptionEndogenous activation of anticipatory image (effect event)

Serial reaction-time taskWhen the effect event is the stimulus to which to

respond (task relevant)The response–stimulus association is a critical component of serial learning

(Ziessler, 1998).When the effect event is redundant Performance is better in response to the contingent tone effects than to random

effects (Drost et al., 2005; Hoffmann et al., 2001), most interrupted whenthe tone effects are altered by serial shift (Pfordresher, 2005), and improvedwhen the effect tones are compatibly assigned to the key locations(Hoffmann et al., 2001).

Choice reaction-time taskTwo-stage learning When the tone (paired with the response in the association phase) is presented

with the stimulus in the test phase, performance is better (Hommel, 1996).Action can be redefined with newly associated effect features (Beckers etal., 2002).

Response–effect compatibility When there is compatible relation between action and its effect, the perfor-mance is better than the incompatible relation (Kunde, 2001b).

Exogenous activation by stimulus eventIdeomotor compatibility Presentation of a stimulus that resembles the following action’s sensory

consequence can activate the action itself (Greenwald, 1972).Biological motion Observing biological motion can evoke a corresponding body-related gesture

(Brass et al., 2000; Sturmer et al., 2000) but not always (Ottoboni et al.,2005).

Ideomotor actionIntentional ideomotor action An act to try to change the direction of a ball desirably occurred in the

billiard-like task even after the effective control action was completed forthe hand effector (Knuf et al., 2001).

Perceptually induced ideomotor action Perceptual ideomotor action was weakly found for the foot and the headeffectors, and it was guided by the most dynamic moving scene (Knuf et al.,2001).

Modulation of perception by actionContrast Disruption of the perceptual process, or perceptual bias in a direction opposite

to that of planned or concurrent action (Musseler & Hommel, 1997a,1997b).

Assimilation Enhancement of detection or identification of the stimulus, or perceptual biasin the same direction as the action (Craighero et al., 1999).

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tive models. For instance, Kornblum’s (1992) dimensional overlapmodel also suggests a common representation in a higher mentalarchitecture, where perception and action features overlap to referthe same abstract property such as left. Little empirical evidencehas been found that would dissociate the dimensional overlapmodel and common coding theory experimentally with respect toSRC effects. Though Prinz (1997) introduced the orthogonal SRCeffect (up/right–down/left mapping advantage; Weeks & Proctor,1990) as evidence against the dimensional overlap model, thateffect does not seem to favor the common coding theory. Rather,the orthogonal SRC effect has been explained by dimensionaloverlap of asymmetric structural features, which can be calledpolarity correspondence (for review, see Cho & Proctor, 2003).Thus, when an ideomotor-related model confines its explanatorylevel to the highly cognitive area of early action, its acceptanceshould depend on demonstration that it can be separated from othercognitive models in which perception and action codes are as-sumed to overlap in some manner. Kunde (2001a) also suggestedthat more specification of “late action” is necessary for a compre-hensive theory about how abstract action codes can select oneparticular candidate from among an infinite number to achieve adesired state.

Some ideomotor accounts focus on a specific domain for per-ception and action such as biological motion or imitation (Cate-gory 2) and have been supported by numerous neurophysiologicalfindings. These studies can be divided into those that focus onamodal representation of action and perception, such as mirrorneuron accounts, or modal representation of perception onto motorneural correlates, such as Jeannerod’s (2001) account. Observingor imaging of action was reported to provoke the same neuralsubstrates and the same brain areas such as primary motor cortexexcept for a kinesthetic component (Abbruzzese, Trompetto, &Schieppati, 1996). Jeannerod proposed that cortical motor areasare primarily involved in mental imagery and also in observation,planning, and verbalization of actions. He suggested that thisactivity in the motor cortex can be interpreted as a covert stage(e.g., preparation) of action. Idea about action can activate theneural correlates corresponding to the motor command but inhibitsthe outflow signals at some point so that no overt behavior occurs.Otherwise, the idea may activate the descending motor pathways atsubthreshold level (e.g., Hanakawa, Dimyan, & Hallett, 2008). Ifthe inhibition fails or if the idea activates the motor componentabove the threshold level, it will produce involuntary action.Fadiga, Fogassi, Pavesi, and Rizzolatti (1995) even discovered asignificant increase of motor-evoked potentials in the peripheralmotor system, such as in hand muscles, when biological motion isobserved. The findings of these modal representation studies cor-respond to the original ideomotor concept from James (1890/1950). Although the scientific tools to measure brain activity werenot well developed in 1890, James implied that the representationof an idea activates the neural substrates corresponding to motorcontrol. According to him, ideomotor phenomena are those ofseamless operation from idea to action only if one observes,imagines, or represents the action.

A mirror neuron account can be applied to Category 2, but itdoes not suggest that all necessary parameters for the imitativeperformance be specified from observation. Instead, mirror neu-rons seem primarily involved in action semantics, which are re-lated to understanding the intention or goal of an action and early

action planning rather than late planning of construction of thekinematic detail of the action. If area F5 is involved in imitativebehavior, the involvement is in the observer’s imitation of theactor’s intention through the observer’s own interpretation ratherthan exactly copying the actor’s movement. Remember the con-tralateral imitative error for young children mentioned previously.They imitated the goal of the action “touch the left ear” byimprovising the movement in their own manner. Children ignoredother details and focused only on the end state of action. Theflexibility of area F5’s interpretation of action is evolutionarilymore beneficial (that is why the children’s error is often called anintelligent error), since it allows genuine communication withothers. Area F5 is highly overlapped with Broca’s area and isknown to discharge to observations of movements related to thehand and mouth. MacNeilage (1992) suggested that the evolution-ary origin of speech can be traced back to the use of hand gestures.Thus, matching of the observed and executed gestures is theprecursor of the speech communication with others. Area F5 isalso called a mind-reading cell for this reason (e.g., Iacoboni,2008).

However, for this characteristic of the mirror neurons, Vogt(2002) pointed out that motor representations in area F5 are stilltoo abstract for the relevant degrees of freedom corresponding toa motor command to be specified. This indication is analogous toTEC’s dilemma, which set a description boundary to the earlyaction. If one tags a neural correlate of TEC, then area F5 is themost appropriate candidate. Therefore, the question that still re-mains for the mirror neuron hypothesis is whether the hypothesisis indisputably strong if only the early action is considered. Be-cause a certain brain area could be expected to discharge to acertain meaning, for instance, an action’s goal either from theaction itself (planning of a goal) or action observation (understand-ing of action), it is predicted that this outcome occurs.

Category 3 is a weak ideomotor hypothesis, which suggests thatsome additional cognitive steps must be filled in to achieve trans-formation of perception into action. That automatic activation froman idea can be incorrect provides evidence to support this hypoth-esis. Ideomotor compatibility effect studies in the dual-task para-digm can be assigned into this type, since they showed that theeven two IM-compatible tasks disrupted performance when theyhad to be performed simultaneously. But Shin and Proctor (2008)noted that the operational definition of an IM-compatible task wasquestionable and left a further possibility that certain S–R sets suchas biological motion or goal-directed movement (pointing or eyesaccade) may have a minimum level of cost for translating per-ception into action.

Ideomotor apraxia can be a counterexample against the strongideomotor account. Though the consensus definition of the termapraxia is the inability to translate the intended movement into anappropriate motor act, the precise description of the malfunction isstill debated. The critical locus of apraxia has been the disruptedinteraction between cognitive representation and production (e.g.,Halsband, 1998). Since patients with apraxia display normalmovements in many spontaneous daily works, the syndrome isoften characterized as “a disorder of skilled movement not causedby weakness, akinesia, deafferentation, abnormal tone or posture,and movement disorders such as tremors or chorea” (Goldenberg,1995, p. 64). Furthermore, apraxia patients conceptually under-stand what to do but often fail to execute their idea into motion,


even with their intact motor ability. Most of all, they are unable toimitate meaningful (e.g., combing their hair) or meaningless (e.g.,placing an index finger on their nose) gestures or movements byfollowing another’s action (e.g., Ochipa, Rothi, & Heilman, 1989).However, skilled movements, such as connecting beads, remainrelatively intact (Goldenberg, 1995). Some patients conceptuallyunderstand how to use a specific tool (know what to do) but cannotexecute the action for using the tool appropriately (do not knowhow to do). These findings concerning ideomotor apraxia implythat a certain extra bridge is required to be intact to translate ideato action. If a strong ideomotor theory is true, when one knowswhat to do with intact motor skill, planning of action should beconverted into action seamlessly.

For all conflicting sensorimotor coupling hypotheses, the prob-lem often comes from the different levels of description of actionand perception that are subserved by functionally distinct neuralsubsystems, as Norman (2002) stated. Notably, a substantialamount of evidence has suggested that the vision system consistsof two functionally different visual pathways (Milner & Goodale,1995), the ventral and dorsal streams described earlier. Someideomotor researchers have defined clearly what they are referringto as perception in terms of the ventral–dorsal division. Buxbaumet al. (2005) proposed that ideomotor apraxia is attributable todamage in the inferior parietal lobe, which is closely related to theventral system. To achieve successful duplication of another’saction, one must bring about stored information about the other’saction and recalculate the action parameter to produce the actionthrough one’s own spatial body features. In contrast, the relevantinformation for an object-directed movement is delivered online,and the action upon object is unfolded on the same referentialframe for action and perception. The dorsal–ventral division wassupported by double dissociation evidence. Perenin and Vighetto(1988) found that patients with optic ataxia showed deficientability to reach to a target but were frequently unimpaired inimitation behavior. Some have suggested that the dorsal systemmay serve the transformation of perception to action when thestimulus is highly congruent to the action feature (Keller et al.,2006; Waszak et al., 2005). When the perception–action mappingis arbitrary, it requires representation at a higher cognitive level bycross-domain mapping, thought to be achieved by the ventralsystem (Passingham, Toni, & Rushworth, 2000; Wise, di Pelle-grino, & Boussaoud, 1996), which also corresponds to TEC’sdescriptive level. In further studies, researchers should elaborateupon how the dorsal–ventral division coexists with ideomotortheory by specifying their definitions more clearly.

Concluding Remarks

Ideomotor theory was initiated from the question of how an ideaproduces its intended action. The modern version of an answer toWilliam James’s search for how an action is initiated by an ideawas suggested by the ideomotor principle (Greenwald, 1970) andextended in the integrated account of TEC (Hommel et al., 2001).This ideomotor theory has now burgeoned into a framework thathas instigated much research about action and perception, primar-ily fueled by a variety of sensorimotor coupling findings fromneuroscience.

The ideomotor theory, dormant since early in the 20th century,was rediscovered by Greenwald (1970). He suggested that an

action is triggered automatically by anticipation of the sensoryfeedback in more elaborated scientific terms than those accountsfrom the 19th century. The anticipatory process to produce anaction was incorporated into TEC, which was formulated on thebasis of various accounts about the close relation between actionand perception. TEC focuses on the incommensurability betweenaction and perception in terms of their contents and suggests acommon representational domain for perception and action, espe-cially, with the cognitive antecedent of the action. The directlinkage between perception and action has received much supportfrom discoveries in cognitive neuroscience. The ideomotor theorycontinues to encourage research on hypotheses concerning codingof the action effects, a topic that previously had been somewhatneglected in human behavioral models.

References

Aarts, H., Custer, R., & Marien, H. (2008, March 21). Preparing andmotivating behavior outside of awareness. Science, 319, 1639. doi:10.1126/science.1150432

Abbruzzese, G., Trompetto, C., & Schieppati, M. (1996). The excitabilityof the human motor cortex increases during execution and mentalimagination of sequential but not repetitive finger movements. Experi-mental Brain Research, 111, 465–472.

Adams, J. A. (1971). A closed-loop theory of motor learning. Journal ofMotor Behavior, 3, 111–150.

Allport, D. A. (1987). Selection for action: Some behavioral and neuro-physiological consideration of attention and action. In H. Heuer & A. F.Sanders (Eds.), Perspectives on perception and action (pp. 395–419).Hillsdale, NJ: Erlbaum.

Aschersleben, G., & Prinz, W. (1995). Synchronizing actions with events - Therole of sensory information. Perception & Psychophysics, 57, 305–317.

Band, G. P. H., van Steenbergen, H., Ridderinkhof, R. K., Falkenstein, M.,& Hommel, B. (2009). Action-effect negativity: Irrelevant action effectsare monitored like relevant feedback. Biological Psychology, 82, 211–218. doi:10.1016/j.biopsycho.2009.06.011

Bargh, J. A., & Chartrand, T. L. (1999). The unbearable automaticity ofbeing. American Psychologist, 54, 462– 479. doi:10.1037/0003-066X.54.7.462

Bargh, J. A., & Morsella, E. (2008). The unconscious mind. Perspectiveson Psychological Science, 3, 73–79.

Bassler, U. (1977). Sensory control of leg movement in stick insectCarausius morosus. Biological Cybernetics, 25, 61–72.

Bassler, U. (1983). Influence of femoral chordotonal organ afferences onecdysis and on the development of motor programs in locust larvae.Physiological Entomology, 8, 353–357.

Bassler, U. (1987). Timing and shaping influences on the motor output forwalking in stick insects. Biological Cybernetics, 55, 397–401.

Baumeister, R. F., & Vohs, K. D. (2004). Handbook of self-regulation:Research, theory, and application. New York, NY: Guilford Press.

Beckers, T., De Houwer, J., & Eelen, P. (2002). Automatic integration ofnon-perceptual action effect features: The case of the associative affec-tive Simon effect. Psychological Research, 66, 166–173. doi:10.1007/s00426-002-0090-9

Bekkering, H., Brass, M., Woschina, S., & Jacobs, A. M. (2005). Goal-directed imitation in patients with ideomotor apraxia. Cognitive Neuro-psychology, 22, 1–14. doi:10.1080/02643290442000275

Bekkering, H., Wohlschlager, A., & Gattis, M. (2000). Imitation of ges-tures in children is goal-directed. Quarterly Journal of ExperimentalPsychology, 53, 153–164. doi:10.1080/027249800390718

Blank, D. S., Lewis, J. M., & Marshall, J. B. (2005). The multiple roles ofanticipation in developmental robotics. In C. Castelfranchi, C. Balken-ius, M. Butz, & A. Ortony (Program Cochairs), From reactive to

969IDEOMOTOR THEORY

anticipatory cognitive embodied systems (Association for the Advance-ment of Artificial Intelligence Fall Symposium Technical Report FS-05-05). Stanford, CA: AAAI Press.

Bolles, R. C. (1972). Reinforcement, expectancy, and learning. Psycholog-ical Review, 79, 394–409. doi:10.1037/h0033120

Brass, M., Bekkering, H., & Prinz, W. (2001). Movement observationaffects movement execution in a simple response task. Acta Psycho-logica, 106, 3–22. doi:10.1016/S0001-6918%2800%2900024-X

Brass, M., Bekkering, H., Wohlschlager, A., & Prinz, W. (2000). Com-patibility between observed and executed finger movements: Comparingsymbolic, spatial, and imitative cues. Brain and Cognition, 44, 124–143.doi:10.1006/brcg.2000.1225

Brunswik, E. (1944). Distal focusing of perception. Size constancy in arepresentative sample of situations. Psychological Monographs, 56,1–49.

Bush, R. R., Galanter, E., & Luce, R. D. (1963). Characterization andclassification of experiments. In R. D. Luce & R. R. Bush (Eds.),Handbook of mathematical psychology (pp. 77–102). New York, NY:Wiley.

Butz, M. V., Sigaud, O., & Gerard, P. (2003). Intentional models andanticipations in adaptive learning systems. In M. V. Butz, O. Sigaud, &P. Gerard (Eds.) Anticipatory behavior in adaptive learning systems:Foundations, theories, and systems, (pp. 86–109). Heidelberg, Ger-many: Springer.

Buxbaum, L. J., Kyle, K. M., & Menon, R. (2005). On beyond mirrorneurons: Internal representations subserving imitation and recognition ofskilled object-related actions in humans. Cognitive Brain Research, 25,226–239. doi:10.1016/j.cogbrainres.2005.05.014

Carlton, L. G. (1981). Processing visual feedback information for move-ment control. Journal of Experimental Psychology: Human Perceptionand Performance, 7, 1019–1030. doi:10.1037/0096-1523.7.5.1019

Carpenter, W. B. (1852). On the influence of suggestion in modifying anddirecting muscular movement, independently of volition. Proceedings ofthe Royal Institution, 147–154.

Carpenter, W. B. (1874). Principles of mental physiology. London, En-gland: Henry S. King.

Caspy, T., & Lubow, R. E. (1981). Generality of U.S. preexposure effects:Transfer from food to shock or shock to food with and without the sameresponse requirements. Animal Learning & Behavior, 9, 524–532.

Chase, R. A., Harvey, S., Standfast, S., Rapin, I., & Sutton, S. (1961).Studies on sensory feedback: 1. Effect of delayed auditory-feedback onspeech and keytapping. Quarterly Journal of Experimental Psychology,13, 141–152.

Cho, Y. S., & Proctor, R. W. (2003). Stimulus and response representationsunderlying orthogonal stimulus-response compatibility effect. Psy-chonomic Bulletin & Review, 10, 45–73.

Cleeremans, A., & McClelland, J. L. (1991). Learning the structure ofevent sequences. Journal of Experimental Psychology: General, 120,235–253.

Cock, J., & Meier, B. (2007). Incidental task sequence learning: Perceptualrather than conceptual? Psychological Research, 71, 140–151. doi:10.1007/s00426-005-0005-7

Cohen, A., Ivry, R. I., & Keele, S. W. (1990). Attention and structure insequence learning. Journal of Experimental Psychology: Learning,Memory, and Cognition, 16, 17–30. doi:10.1037/0278-7393.16.1.17

Colwill, R. M., & Rescorla, R. A. (1985). Postconditioning devaluation ofa reinforcer affects instrumental responding. Journal of ExperimentalPsychology: Animal Behavior Processes, 11, 120–132. doi:10.1037/0097-7403.11.1.120

Colwill, R. M., & Rescorla, R. A. (1986). Associative structures in instru-mental learning. Psychology of Learning and Motivation: Advances inResearch and Theory, 20, 55–104.

Colwill, R. M., & Rescorla, R. A. (1990). Evidence for the hierarchical

structure of instrumental learning. Animal Learning & Behavior, 18,71–82.

Craighero, L., Fadiga, L., Rizzolatti, G., & Umilta, C. (1999). Action forperception: A motor-visual attentional effect. Journal of ExperimentalPsychology: Human Perception and Performance, 25, 1673–1692. doi:10.1037/0096-1523.25.6.1673

De Houwer, J., & Eelen, P. (1998). An affective variant of the Simon paradigm.Cognition & Emotion, 12, 45–61. doi:10.1080/026999398379772

DeLong, R. E., & Wasserman, E. A. (1981). Effects of differential rein-forcement expectancies on successful matching-to-sample performancein pigeons. Journal of Experimental Psychology: Animal Behavior Pro-cesses, 7, 394–412. doi:10.1037/0097-7403.7.4.394

De Maeght, S., & Prinz, W. (2004). Action induction through actionobservation. Psychological Research, 68, 97–114. doi:10.1007/s00426-003-0148-3

de Wit, S., & Dickinson, A. (2009). Associative theories of goal-directedbehaviour: A case for animal–human translational models. Psychologi-cal Research, 73, 463–476. doi:10.1007/s00426-009-0230-6

Drost, U. C., Rieger, M., Brass, M., Gunter, T. C., & Prinz, W. (2005).When hearing turns into playing: Movement induction by auditorystimuli in pianists. Quarterly Journal of Experimental Psychology: Sec-tion A, 58, 1376–1389. doi:10.1080/02724980443000610

Elsner, B., & Hommel, B. (2001). Effect anticipation and action control.Journal of Experimental Psychology: Human Perception and Perfor-mance, 27, 229–240. doi:10.1037/0096-1523.27.1.229

Elsner, B., & Hommel, B. (2004). Contiguity and contingency in action-effect learning. Psychological Research, 68, 138–154. doi:10.1007/s00426-003-0151-8

Fadiga, L., Fogassi, L., Pavesi, G., & Rizzolatti, G. (1995). Motor facili-tation during action observation: A magnetic stimulation study. Journalof Neurophysiology, 73, 2608–2611.

Fedorchak, P. M., & Bolles, R. C. (1986). Differential outcome effect usinga biologically neutral outcome difference. Journal of Experimental Psy-chology: Animal Behavior Processes, 12, 125–130. doi:10.1037/0097-7403.12.2.125

Finney, S. A. (1997). Auditory feedback and musical keyboard perfor-mance. Music Perception, 15, 153–174.

Finney, S. A., & Palmer, C. (2003). Auditory feedback and memory formusic performance: Sound evidence for an encoding effect. Memory &Cognition, 31, 51–64.

Gibson, J. J. (1950). Perception of the visual world, Boston, MA: Hough-ton Mifflin.

Goldenberg, G. (1995). Imitating gestures and manipulating a mannikin:The representation of the human body in ideomotor apraxia. Neuropsy-chologia, 33, 63–72. doi:10.1016/0028-3932%2894%2900104-W

Gordon, P. C., & Meyer, D. E. (1987). Control of serial order in rapidlyspoken syllable sequences. Journal of Memory and Language, 26, 300–321. doi:10.1016/0749-596X%2887%2990116-1

Greenwald, A. G. (1970). Sensory feedback mechanisms in performancecontrol: With special reference to the ideo-motor mechanism. Psycho-logical Review, 77, 73–99. doi:10.1037/h0028689

Greenwald, A. G. (1972). On doing two things at once: Timesharing as afunction of ideomotor compatibility. Journal of Experimental Psychol-ogy, 94, 52–57. doi:10.1037/h0032762

Greenwald, A. G. (2003). On doing two things at once: III. Confirmationof perfect timesharing when simultaneous tasks are ideomotor compat-ible. Journal of Experimental Psychology: Human Perception and Per-formance, 29, 859– 868.

Greenwald, A. G., & Shulman, H. G. (1973). On doing two things at once:II. Elimination of the psychological refractory period effect. Journal ofExperimental Psychology, 101, 70–76. doi:10.1037/h0035451

Haggard, P., Clark, S., & Kalogeras, J. (2002). Voluntary action andconscious awareness. Nature Neuroscience, 5, 382–385. doi:10.1038/nn827


Halsband, U. (1998). Brain mechanisms of apraxia. In A. D. Milner (Ed.),Comparative neuropsychology (pp. 184–212). Oxford, England: OxfordUniversity Press.

Hamilton, A., Wolpert, D., & Frith, U. (2004). Your own action influenceshow you perceive another person’s action. Current Biology, 14, 493–498. doi:10.1016/j.cub.2004.03.007

Hanakawa, T., Dimyan, M. A., & Hallett, M. (2008). Motor planning,imagery, and execution in the distributed motor network: A time-coursestudy with functional MRI. Cerebral Cortex, 18, 2775–2788. doi:10.1093/cercor/bhn036

Harless, E. (1861). Der Apparat des Willens [The apparatus of the will]. InI. H. Fichte, H. Ulrici & I. U. Wirth (Eds.), Zeitschrift fur Philosophieund philosophische Kritik [Magazine for philosophy and philosophicalcriticism], 38, 50–73. Halle, Germany: Pfeffer.

Heider, F. (1959). The function of the perceptual system [Monograph].Psychological Issues, 1, 135–152. (Original work published 1930)

Heider, F. (1959). Thing and medium [Monograph]. Psychological Issues,1(3), 1–34. (Original work published 1926)

Herbart, J. F. (1816). Lehrbuch zur Psychologie [Textbook for psychol-ogy]. Königsberg, Germany: Unzer.

Herbart, J. F. (1825). Psychologie als Wissenschaft neu gegrundet aufErfahrung, Metaphysik und Mathematik. Zweiter, analytischer Teil[Psychology as science based on experience, metaphysics, and mathe-matics: Part 2]. Königsberg, Germany: Unzer.

Hick, W. E. (1952). On the rate of gain of information. Quarterly Journalof Experimental Psychology, 4, 11–26.

Hoffmann, J., & Koch, I. (1997). Stimulus–response compatibility andsequential learning in the serial reaction time task. Psychological Re-search, 60, 87–97. doi:10.1007/BF00419682

Hoffmann, J., Sebald, A., & Stöcker, C. (2001). Irrelevant response effectsimprove serial learning in serial reaction time tasks. Journal of Exper-imental Psychology: Learning, Memory, and Cognition, 27, 470–482.doi:10.1037/0278-7393.27.2.470

Hommel, B. (1993). Inverting the Simon effect by intention: Determinantsof direction and extent of effects of irrelevant spatial information.Psychological Research, 55, 270–279.

Hommel, B. (1996). The cognitive representation of action: Automaticintegration of perceived action effects. Psychological Research, 59,176–186. doi:10.1007/BF00425832

Hommel, B. (2003). Planning and representing intentional action. ScientificWorld Journal, 3, 593–608.

Hommel, B. (2004). Coloring an action: Intending to produce color eventseliminates the Stroop effect. Psychological Research, 68, 74–90. doi:10.1007/s00426-003-0146-5

Hommel, B. (2007a). Consciousness and control: Not identical twins.Journal of Consciousness Studies, 14, 155–176.

Hommel, B. (2007b). Feature integration across perception and action:Event files affect response choice. Psychological Research, 71, 42–63.doi:10.1007/s00426-005-0035-1

Hommel, B. (2009). Action control according to TEC (theory of eventcoding). Psychological Research, 73, 512–526. doi:10.1007/s00426-009-0234-2

Hommel, B., Alonso, D., & Fuentes, L. J. (2003). Acquisition and gener-alization of action effects. Visual Cognition, 10, 965–986.

Hommel, B., & Lippa, Y. (1995). S–R compatibility effects due to context-dependent spatial stimulus coding. Psychonomic Bulletin & Review, 2,370–374.

Hommel, B., & Musseler, J. (2006). Action–feature integration blinds tofeature-overlapping perceptual events: Evidence from manual and vocal.Quarterly Journal of Experimental Psychology, 59, 509–523.

Hommel, B., Musseler, J., Aschersleben, G., & Prinz, W. (2001). Thetheory of event coding (TEC): A framework for perception and actionplanning. Behavioral and Brain Sciences, 24, 849–937.

Howard, J. H., Mutter, S. A., & Howard, D. V. (1992). Serial pattern

learning by event observation. Journal of Experimental Psychology:Learning, Memory, and Cognition, 18, 1029–1039. doi:10.1037/0278-7393.18.5.1029

Howell, P., & Powell, D. J. (1987). Delayed auditory-feedback withdelayed sounds varying in duration. Perception & Psychophysics, 42,166–172.

Hull, C. L. (1931). Goal attraction and directing ideas conceived as habitphenomena. Psychological Review, 38, 487–506. doi:10.1037/h0071442

Iacoboni, M. (2008). Mirroring people: The new science of how we connectwith others. New York, NY: Farrar, Straus, and Giroux.

Iacoboni, M., Molnar-Szakacs, I., Gallese, V., Buccino, G., Mazziotta,J. C., & Rizzolatti, G. (2005). Grasping the intentions of others withone’s own mirror neuron system. Public Library of Science Biology, 3,529–535.

Ideomotor. (n.d.). In Merriam-Webster’s online dictionary (11th ed.).Retrieved from http://www.merriam-webster.com/dictionary/ideomotor

Ishimura, G., & Shimojo, S. (1994). Voluntary action captures visualmotion. Sarasota, FL: Association for Research in Ophthalmology andVisual Science.

James, W. (1950). The principles of psychology: Vol. 2. New York, NY:Dover. (Original work published 1890)

Jansson, E., Wilson, A. D., Williams, J. H. G., & Mon-Williams, M.(2007). Methodological problems undermine tests of the ideo-motorconjecture. Experimental Brain Research, 182, 549–558.

Jeannerod, M. (2001). Neural simulation of action: A unifying mechanismfor motor cognition. Neuroimage, 14, 103–109.

Kahneman, D., Treisman, A., & Gibbs, B. J. (1992). The reviewing ofobject files: Object-specific integration of information. Cognitive Psy-chology, 24, 175–219. doi:10.1016/0010-0285%2892%2990007-O

Keele, S. W., Jennings, P., Jones, S., Caulton, D., & Cohen, A. (1995). Onthe modularity of sequence representation. Journal of Motor Behavior,27, 17–30.

Keller, P. E., Wascher, E., Prinz, W., Waszak, F., Koch, I., & Rosenbaum,D. A. (2006). Differences between intention-based and stimulus-basedactions. Journal of Psychophysiology, 20, 9–20. doi:10.1027/0269-8803.20.1.9

Klapp, S. T., Anderson, W. G., & Berrian, R. W. (1973). Implicit speechin reading, reconsidered. Journal of Experimental Psychology, 100,368–374. doi:10.1037/h0035471

Klatzky, R. L. (1998). Allocentric and egocentric spatial representations:Definitions, distinctions, and interconnections. In C. Freska, C. Habel, &K. F. Wender (Eds.), Spatial cognition: An interdisciplinary approach torepresentation and processing of spatial knowledge (pp. 1–17). Berlin,Germany: Springer-Verlag.

Knuf, L., Aschersleben, G., & Prinz, W. (2001). An analysis of ideomotoraction. Journal of Experimental Psychology: General, 130, 779–798.doi:10.1037/0096-3445.130.4.779

Koch, I. (2001). Automatic and intentional activation of task sets. Journalof Experimental Psychology: Learning, Memory, and Cognition, 27,1474–1486. doi:10.1037/0278-7393.27.6.1474

Koch, I., & Hoffmann, J. (2000). The role of stimulus-based and response-based spatial information in sequence learning. Journal of ExperimentalPsychology: Learning Memory and Cognition, 26, 863– 882. doi:10.1037/0278-7393.26.4.863

Koch, I., & Kunde, W. (2002). Verbal response-effect compatibility. Mem-ory & Cognition, 30, 1297–1303.

Kornblum, S. (1992). Dimensional overlap and dimensional relevance instimulus–response and stimulus–stimulus compatibility. In G. E. Stelm-ach & J. Requin (Eds.), Tutorials in motor behavior II (pp. 743–777).Amsterdam, the Netherlands: Elsevier.

Kornblum, S., Hasbroucq, T., & Osman, A. (1990). Dimensional overlap:Cognitive basis for stimulus–response compatibility–A model and tax-onomy. Psychological Review, 97, 253–270. doi:10.1037/0033-295X.97.2.253

971IDEOMOTOR THEORY

Kray, J., Eenshuistra, R., Kerstner, H., Weidema, M., & Hommel, B.(2006). Language and action control: The acquisition of action goals inearly childhood. Psychological Science, 17, 737–741. doi:10.1111/j.1467-9280.2006.01774.x

Kunde, W. (2001a). Exploring the hyphen in ideo-motor action. Behavioraland Brain Science, 24, 891–892.

Kunde, W. (2001b). Response–effect compatibility in manual choice re-action tasks. Journal of Experimental Psychology: Human Perceptionand Performance, 27, 387–394. doi:10.1037/0096-1523.27.2.387

Kunde, W. (2003). Temporal response-effect compatibility. PsychologicalResearch, 67, 153–159. doi:10.1007/s00426-002-0114-5

Kunde, W., Hoffmann, J., & Zellmann, P. (2002). The impact of antici-pated action effects on action planning. Acta Psychologica, 109, 137–155. doi:10.1016/S0001-6918%2801%2900053-1

Kunde, W., Koch, I., & Hoffmann, J. (2004). Anticipated action effectsaffect the selection, initiation, and execution of actions. Quarterly Jour-nal of Experimental Psychology, Section A: Human Experimental Psy-chology, 57, 87–106. doi:10.1080/02724980343000143

Kunde, W., & Wuhr, P. (2004). Actions blind to conceptually overlappingstimuli. Psychological Research, 68, 199–207.

Lamb, J., & Kaufman, H. (1965). Information transmission with unequallylikely alternatives. Perceptual and Motor Skills, 21, 255–259.

Lattal, K. A., & Gleeson, S. (1990). Response acquisition with delayedreinforcement. Journal of Experimental Psychology: Animal BehaviorProcesses, 16, 27–39. doi:10.1037/0097-7403.16.1.27

Laycock, T. (1845). On the reflex functions of the brain. In Reprinted fromN. XXXVII of The British and Foreign Medical Review (pp. 1–16).London, England: Adlard.

Laycock, T. (1860). Mind and brain: Or, the correlations of consciousnessand organisation: Vol. II. Edinburgh, Scotland: Sutherland & Knox.

Lewicki, P., Czyzewska, M., & Hoffman, H. (1987). Unconscious acqui-sition of complex procedural knowledge. Journal of Experimental Psy-chology: Learning, Memory, and Cognition, 13, 523–530. doi:10.1037/0278-7393.13.4.523

Lien, M.-C., McCann, R. E., Ruthruff, E., & Proctor, R. W. (2005).Dual-task performance with ideomotor compatible tasks: Is the centralprocessing bottleneck intact, bypassed, or shifted in locus? Journal ofExperimental Psychology: Human Perception and Performance, 31,122–144. doi:10.1037/0096-1523.31.1.122

Lien, M.-C., Proctor, R. W., & Allen, P. A. (2002). Ideomotor compati-bility in the psychological refractory period effect: 29 years of oversim-plification. Journal of Experimental Psychology: Human Perception andPerformance, 28, 396–409. doi:10.1037/0096-1523.28.2.396

Lien, M.-C., Proctor, R. W., & Ruthruff, E. (2003). Still no evidence forperfect timesharing with two ideomotor-compatible tasks: A reply toGreenwald (2003). Journal of Experimental Psychology: Human Per-ception and Performance, 29, 1267–1272. doi:10.1037/0096-1523.29.6.1267

Livingstone, M., & Hubel, D. (1988, May 6). Segregation of form, color,movement, and depth: Anatomy, physiology, and perception. Science,240, 740–749. doi:10.1126/science.3283936

Lotze, R. H. (1852). Medizinische Psychologie oder Physiologie der Seele[Medical psychology or physiology of the soul]. Leipzig, Germany:Weidmannsche Buchhandlung.

MacKay, D. G. (1982). The problems of flexibility, fluency, and speed-accuracy trade-off in skilled behavior. Psychological Review, 89, 483–506. doi:10.1037/0033-295X.89.5.483

MacKay, D. G. (1986). Self-inhibition and the disruptive effects of internaland external feedback in skilled behavior. In H. Heuer & C. Fromm(Eds.), Generation and modulation of action patterns (pp. 174–186).New York, NY: Springer.

MacKay, D. G. (1987). Asymmetries in the relationship between speechperception and production. In H. Heuer & A. F. Sanders (Eds.), Per-

spectives on perception and action (pp. 301–333). Hillsdale, NJ: Erl-baum.

MacNeilage, P. (1992). Evolution and lateralization of the two greatprimate action systems. In J. Wind, B. Chiarelli, B. Bichakjian, & A.Nocentini (Eds.), Language origin: A multidisciplinary approach. Dor-drecht, the Netherlands: Kluwer.

Meck, W. H. (1985). Postreinforcement signal-processing. Journal ofExperimental Psychology: Animal Behavior Processes, 11, 52–70. doi:10.1037/0097-7403.11.1.52

Meltzoff, A. N., & Moore, M. K. (1977, October 7). Imitation of facial andmanual gestures by human neonates. Science, 198, 75–78. doi:10.1126/science.198.4312.75

Meltzoff, A. N., & Moore, M. K. (1997). Explaining facial imitation: Atheoretical model. Early Development and Parenting, 6, 179–192.

Meltzoff, A. N., & Prinz, W. (Eds.) (2002). The imitative mind: Develop-ment, evolution, and brain bases. New York, NY: Cambridge UniversityPress.

Milner, A. D., & Goodale, M. A. (1995). The visual brain in action.Oxford, UK: Oxford University Press.

Morin, R. E., & Grant, D. A. (1955). Learning and performance of akey-pressing task as a function of the degree of spatial stimulus-responsecorrespondence, Journal of Experimental Psychology, 49, 39–47. doi:10.1037/h0041584

Mowrer, O. H. (1960). Learning theory and symbolic processes. NewYork, NY: Wiley.

Munn, N. L. (1950). Handbook of psychological research on the rat.Boston, MA: Houghton Mifflin.

Musseler, J., & Hommel, B. (1997a). Blindness to response-compatiblestimuli. Journal of Experimental Psychology: Human Perception andPerformance, 23, 861–872. doi:10.1037/0096-1523.23.3.861

Musseler, J., & Hommel, B. (1997b). Detecting and identifying response-compatible stimuli. Psychonomic Bulletin & Review, 4, 125–129.

Nattkemper, D., & Prinz, W. (1997). Stimulus and response anticipation ina serial reaction task. Psychological Research, 60, 98–112. doi:10.1007/BF00419683

Nattkemper, D., & Ziessler, M. (2004). Cognitive control of action: Therole of action effects. Psychological Research, 68, 71–73. doi:10.1007/s00426-003-0145-6

Nissen, M. J., & Bullemer, P. (1987). Attentional requirements of learning:Evidence from performance measures. Cognitive Psychology, 19, 1–32.doi:10.1016/0010-0285%2887%2990002-8

Norman, J. (2002). Two visual systems and two theories of perception: Anattempt to reconcile the constructivist and ecological approaches. Be-havioral and Brain Science, 25, 73–96.

Ochipa, C., Rothi, L. J. G., & Heilman, K. M. (1989). Ideational apraxia:A deficit in tool selection and use. Annals of Neurology, 25, 190–193.doi:10.1002/ana.410250214

Ottoboni, G., Tessari, A., Cubeli, R., & Umilta, C. (2005). Is handednessrecognition automatic? A study using a Simon-like paradigm. Journal ofExperimental Psychology: Human Perception and Performance, 31,778–789. doi:10.1037/0096-1523.31.4.643b

Parsons, L. M. (1987). Imagined spatial transformation of one’s body.Journal of Experimental Psychology: General, 116, 172–191. doi:10.1037/0096-3445.116.2.172

Pashler, H. (1994). Dual-task interference in simple tasks: Data and theory.Psychological Bulletin, 116, 220 –244. doi:10.1037/0033-2909.116.2.220

Passingham, R. E., Toni, I., & Rushworth, M. F. S. (2000). Specialisationwithin the prefrontal cortex: The ventral prefrontal cortex and associa-tive learning. Experimental Brain Research, 133, 103–113. doi:10.1007/s002210000405

Perenin, M. T., & Vighetto, A. (1998). Optic ataxia: A specific disruptionin visuomotor mechanisms: I. Different aspects of the deficit in reachingfor objects. Brain, 111, 643–674.


Pfordresher, P. Q. (2003). Auditory feedback in music performance: Evi-dence for a dissociation of sequencing and timing. Journal of Experi-mental Psychology: Human Perception and Performance, 29, 949–964.doi:10.1037/0096-1523.29.5.949

Pfordresher, P. Q. (2005). Auditory feedback in music performance: Therole of melodic structure and musical skill. Journal of ExperimentalPsychology: Human Perception and Performance, 31, 1331–1345. doi:10.1037/0096-1523.31.6.1331

Pfordresher, P. Q., & Palmer, C. (2002). Effects of delayed auditoryfeedback on timing of music performance. Psychological Research, 66,71–79. doi:10.1007/s004260100075

Pfordresher, P. Q., & Palmer, C. (2006). Effects of hearing the past,present, or future during music performance. Perception & Psychophys-ics, 68, 362–376.

Prinz, W. (1987). Ideo-motor action. In H. Heuer & A. F. Sanders (Eds.),Perspectives on perception and action (pp. 47–76). Hillsdale, NJ: Erl-baum.

Prinz, W. (1997). Perception and action planning. European Journal ofCognitive Psychology, 9, 129–154. doi:10.1080/713752551

Proctor, R. W., & Vu, K. P. L. (2006). The cognitive revolution at age 50:Has the promise of the human information-processing approach beenfulfilled? International Journal of Human-Computer Interaction, 21,253–284. doi:10.1207/s15327590ijhc2103_1

Proctor, R. W., & Wang, H. F. (1997). Set- and element-level stimulus-response compatibility effects for different manual response sets. Jour-nal of Motor Behavior, 29, 351–365.

Rescorla, R. A. (1991). Association of multiple outcomes with instrumen-tal response. Journal of Experimental Psychology: Animal BehaviorProcesses, 17, 465–474.

Rescorla, R. A. (1995). Full preservation of a response-outcome associa-tion through training with a 2nd outcome. Quarterly Journal of Exper-imental Psychology, 48B, 252–261.

Rescorla, R. A., & Colwill, R. M. (1989). Associations with anticipatedand obtained outcomes in instrumental learning. Animal Learning &Behavior, 17, 291–303.

Rescorla, R. A., & Solomon, R. L. (1967). Two-process learning theory:Relationship between Pavlovian conditioning and instrumental learning.Psychological Review, 74, 151–182. doi:10.1037/h0024475

Restle, F. (1957). Discrimination of cues in mazes: A resolution of the“place-vs.-response” question. Psychological Review, 64, 217–228. doi:10.1037/h0040678

Rieger, M. (2007). Letters as visual-action effects in skilled typing. ActaPsychologica, 126, 138–153. doi:10.1016/j.actpsy.2006.11.006

Rizzolatti, G. (2005). The mirror neuron system and imitation. In S. Hurley& N. Chater (Eds.), Perspectives on imitation: From neuroscience tosocial science: Vol. 1. Mechanisms of imitation and imitation in animals(pp. 55–76). Cambridge, MA: MIT Press.

Rizzolatti, G., Fadiga, L., Galleses, V., & Fogassi, L. (1996). Premotorcortex and the recognition of motor actions. Cognitive Brain Research,3, 131–141.

Rosen, R. (1985). Anticipatory systems. London, England: PergamonPress.

Rosenbaum, D. A., Kenny, S. B., & Derr, M. A. (1983). Hierarchicalcontrol of rapid movement sequences. Journal of Experimental Psychol-ogy: Human Perception and Performance, 9, 86–102. doi:10.1037/0096-1523.9.1.86

Rosenbaum, D. A., Marchak, F., Barnes, H. J., Vaughan, J., Slotta, J. D.,& Jorgensen, M. J. (1990). Constraints for action selection: Overhandversus underhand grips. In M. Jeannerod (Ed.), Attention and perfor-mance XIII: Motor representation and control (pp. 321–342). Hillsdale,NJ: Erlbaum.

Rothi, L. J., & Ochipa, C. (1991). A cognitive neuropsychological modelof limb praxis. Cognitive Neuropsychology, 8, 443–458. doi:10.1080/02643299108253382

Schubö, A., Prinz, W., & Aschersleben, G. (2004). Perceiving while acting:Action affects perception. Psychological Research, 68, 208–215.

Schubotz, R. I., & von Cramon, D. Y. (2001). Functional organization ofthe lateral premotor cortex: fMRI reveals different regions activated byanticipation of object properties, location and speed. Cognitive BrainResearch, 11, 97–112.

Schutz-Bosbach, S., & Prinz, W. (2007). Perceptual resonance: Action-induced modulation of perception. Trends in Cognitive Sciences, 11,349–355. doi:10.1016/j.tics.2007.06.005

Sekiyama, K. (1982). Kinesthetic aspects of mental representations in theidentification of left and right hands. Perception & Psychophysics, 32,89–95.

Shin, Y. K., Cho, Y. S., Lien, M.-C., & Proctor, R. W. (2007). Is thepsychological refractory period effect for ideomotor-compatible taskseliminated by speed-stress instruction? Psychological Research, 71,553–567. doi:10.1007/s00426-006-0066-2

Shin, Y. K., & Proctor, R. W. (2008). Are spatial responses to visuospatialstimuli and spoken responses to auditory letters ideomotor-compatibletasks? Examination of set-size effects on dual-task interference. ActaPsychologica, 129, 352–364.

Simon, J. R. (1990). The effects of an irrelevant directional cue on humaninformation processing. In R. W. Proctor & T. G. Reeve (Eds.),Stimulus–response compatibility: An integrated perspective (pp. 31–86).Amsterdam, the Netherlands: North-Holland.

Singer, W. (1994). The organization of sensory-motor representations inthe neocortex: A hypothesis based on temporal coding. In C. Umilta &M. Moscovitch (Eds.), Attention and performance XV: Conscious andnonconscious information (pp. 77–107). Cambridge, MA: MIT Press.

Spence, K. W. (1956). Behavior theory and conditioning. New Haven, CT:Yale University Press.

Stock, A., & Stock, C. (2004). A short history of ideo-motor action.Psychological Research, 68, 176–188.

Stöcker, C., Sebald, A., & Hoffmann, J. (2003). The influence of response-effect compatibility in a serial reaction time task. Quarterly Journal ofExperimental Psychology; Section A, 56, 685–703. doi:10.1080/02724980244000585

Sturmer, B., Aschersleben, G., & Prinz, W. (2000). Correspondence effectswith manual gestures and postures: A study of imitation. Journal ofExperimental Psychology: Human Perception and Performance, 26,1746–1759. doi:10.1037/0096-1523.26.6.1746

ten Hoopen, G., Akerboom, S., & Raaymakers, E. (1982). Vibrotactualchoice reaction-time, tactile receptor systems and ideomotor compati-bility. Acta Psychologica, 50, 143–157.

Thorndike, E. L. (1905). The elements of psychology: New York, NY:Seiler.

Thorndike, E. L. (1913). Ideo-motor action. Psychological Review, 20,91–106. doi:10.1037/h0072027

Trapold, M. A. (1970). Are expectancies based upon different positivereinforcing events discriminably different. Learning and Motivation, 1,129–140.

Trapold, M. A., & Overmeier, J. B. (1972). The second learning process ininstrumental learning. In A. H. Black & W. F. Prokasy (Eds.), Classicalconditioning II: Current theory and research (pp. 427–452). New York,NY: Appleton-Century-Crofts.

Treisman, A., & Schmidt, H. (1982). Illusory conjunctions in the percep-tion of objects. Cognitive Psychology, 14, 107–141. doi:10.1016/0010-0285%2882%2990006-8

Umilta, C. (1988). The control operations of consciousness. In A. J. Marcel& E. Bisiach (Eds.), Consciousness in contemporary science. Oxford,England: Oxford University Press.

Urcuioli, P. J., & DeMarse, T. (1996). Associative processes in differentialoutcome discriminations. Journal of Experimental Psychology: AnimalLearning and Behavior, 22, 192–204. doi:10.1037/0097-7403.22.2.192

Usher, M., Olami, Z., & McClelland, J. L. (2002). Hick’s law in a

973IDEOMOTOR THEORY

stochastic race model with speed-accuracy tradeoff. Journal of Mathe-matical Psychology, 46, 704–715. doi:10.1006/jmps.2002.1420

Viswanathan, N., Tobin, S. J., Fowler, C. A., & Magnuson, J. S. (2008,November). Motor compatibility effects on speech perception. Postersession presented at the 49th annual meeting of the Psychonomic Soci-ety, Chicago, IL.

Vogt, S. (2002). Visuomotor couplings in object-oriented and imitativeactions. In A. Meltzoff & W. Prinz (Eds.), The imitative mind: Devel-opment, evolution, and brain bases (pp. 206–220). New York, NY:Cambridge University Press.

Volition. (n.d.-a). In Wikitionary. Retrieved from http://en.wiktionary.org/wiki/volition

Volition. (n.d.-b). In WordNet [Database]. Retrieved from http://wordnetweb.princeton.edu/perl/webwn?s�volition

Wang, D.-Y. D., Proctor, R. W., & Pick, D. F. (2007). Coding controlledand triggered cursor movements as action effects: Influences on theauditory Simon effect for wheel-rotation responses. Journal of Experi-mental Psychology: Human Perception and Performance, 33, 657–669.

Waszak, F., Wascher, E., Keller, P., Koch, I., Aschersleben, G., Rosen-baum, D. A., & Prinz, W. (2005). Intention-based and stimulus-basedmechanisms in action selection. Experimental Brain Research, 162,346–356. doi:10.1007/s00221-004-2183-8

Weeks, D. J., & Proctor, R. W. (1990). Salient-features coding in thetranslation between orthogonal stimulus and response dimensions. Jour-nal of Experimental Psychology: General, 119, 355–366.

Wegner, D. (2003). The mind’s best trick: How we experience consciouswill. Trends in Cognitive Sciences, 7, 65– 68. doi:10.1016/S1364-6613%2803%2900002-0

Westwood, D. A., & Goodale, M. A. (2001). Perception and action plan-ning: Getting it together. Behavioural and Brain Sciences, 24, 907–908.

Willingham, D. B., Nissen, M. J., & Bullemer, P. (1989). On the devel-opment of procedural knowledge. Journal of Experimental Psychology:Learning, Memory, and Cognition, 15, 1047–1060. doi:10.1037/0278-7393.15.6.1047

Wise, S. P., di Pellegrino, G., & Boussaoud, D. (1996). The premotorcortex and nonstandard sensorimotor mapping. Canadian Journal of

Physiology and Pharmacology, 74, 469–482. doi:10.1139/cjpp-74-4-469

Witt, J. K., Proffitt, D. R., & Epstein, W. (2005). Tool use affects perceiveddistance, but only when you intend to use it. Journal of ExperimentalPsychology: Human Perception and Performance, 31, 880–888. doi:10.1037/0096-1523.31.5.880

Wohlschlager, A. (2000). Visual motion priming by invisible actions. VisionResearch, 40, 925–930. doi:10.1016/S0042-6989%2899%2900239-4

Wolpert, D. M. (1997). Internal models in human motor control: A com-putational and psychophysical perspective. Journal of Physiology (Lon-don), 501P, S12–S12.

Wright, C. E., Marino, V. F., Belovsky, S. A., & Chubb, C. (2007).Visually guided, aimed movements can be unaffected by stimulus-response uncertainty. Experimental Brain Research, 179, 475–496.

Wuhr, P., & Musseler, J. (2002). Blindness to response-compatible stimuliin the psychological refractory period paradigm. Visual Cognition, 9,421–457. doi:10.1080/13506280143000520

Ziessler, M. (1994). The impact of motor responses on serial-patternlearning. Psychological Research, 57, 30–41. doi:10.1007/BF00452993

Ziessler, M. (1998). Response-effect learning as a major component ofimplicit serial learning. Journal of Experimental Psychology: Learning,Memory, and Cognition, 24, 962–978. doi:10.1037/0278-7393.24.4.962

Ziessler, M., & Nattkemper, D. (2001). Learning of event sequences isbased on response-effect learning: Further evidence from serial reactiontask. Journal of Experimental Psychology: Learning, Memory, andCognition, 27, 595–613. doi:10.1037/0278-7393.27.3.595

Ziessler, M., & Nattkemper, D. (2002). Effect anticipation in action plan-ning. In W. Prinz & B. Hommel (Eds.), Attention and performance XIX:Common mechanisms in perception and action (pp. 645–672). Oxford,England: Oxford University Press.

Ziessler, M., Nattkemper, D., & Frensch, P. (2004). The role of anticipationand intention in the learning of effects of self-performed actions. Psy-chological Research, 68, 163–175. doi:10.1007/s00426-003-0153-6

Received April 9, 2009Revision received May 4, 2010

Accepted May 17, 2010 �

Correction to Shin et al. (2010)

In the Online First Publication of the article “A Review of Contemporary Ideomotor Theory” byYun Kyoung Shin, Robert W. Proctor, and E. J. Capaldi (Psychological Bulletin, posted September6, 2010, doi: 10.1037/a0020541), the title of the article was incorrectly listed as “A Review ofContemporary Idiomatic Theory.” All versions of this article have been corrected.

DOI: 10.1037/a0021628


A Review of Contemporary Ideomotor Theory

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