Bodies and other visual objects: the dialectics of reaching toward objects
-
Upload
mike-tucker -
Category
Documents
-
view
214 -
download
1
Transcript of Bodies and other visual objects: the dialectics of reaching toward objects
![Page 1: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/1.jpg)
ORIGINAL ARTICLE
Bodies and other visual objects: the dialectics of reachingtoward objects
Rob Ellis • Dan Swabey • John Bridgeman •
Benjamin May • Mike Tucker • Amanda Hyne
Received: 4 May 2011 / Accepted: 5 November 2011 / Published online: 19 November 2011
� Springer-Verlag 2011
Abstract Participants viewed video clips of a left or
right-handed reach toward an object that was orientated
with a handle to the left or right. They were required to
classify the object by making a left or right-handed key-
press and ignore the reach. These responses were, never-
the-less, affected by the observed reach in ways which
largely reflected the opportunities for complementary
actions in the viewed scenes, given the simultaneous con-
straints of the object orientation combined with the direc-
tion and hand of reach. These influences are claimed to
reflect the interdependency of the action possibilities that
arise from a set of objects and agents in three-dimensional
space that together determine behaviour.
Introduction
It is increasingly recognised that cognition should not be
regarded as a set of disembodied processes, but is strongly
determined by the constraints of its bodily implementation.
In the case of visual cognition, this embodied approach has
led to an emphasis on the role of vision in exploring the
world and, therefore, on the integration of vision and
action. It has been argued, for instance, that the action
properties of objects are an intrinsic part of its mental
representation. Evidence for this view includes a series of
studies employing a stimulus–response compatibility par-
adigm (Tucker & Ellis, 1998, 2001; Ellis & Tucker, 2000)
showing that the sight of an object potentiates (affords) the
actions associated with it. So for instance when participants
viewed an object to judge whether it was manufactured or
organic, their responses were facilitated when compatible
with an action needed to handle the object (a precision grip
for a pea or a power grip for a hammer are examples)
compared to the incompatible cases. Entirely analogous
object to action compatibility effects (which we term
micro-affordance) were observed for other elements of a
reach-to-grasp action: the hand of response and the direc-
tion of wrist rotation. The effects appear to be the results of
object-based attention, in that attending to a location on an
object does not necessarily elicit micro-affordance (Vainio,
Ellis, & Tucker, 2007) and an ignored object does not
produce action compatibility effects provided the target
object is cued by location (Ellis, Tucker, Symes, & Vainio,
2007). It seems that viewing an object, as an object,
potentiates the actions associated with it irrespective of
whether there is an intention in the viewer to act on it.
Similar action potentiation effects were observed when
participants classified named graspable objects (Tucker &
Ellis, 2004) or recalled previously seen objects (Derby-
shire, Ellis, & Tucker, 2006). It is concluded that micro-
affordance is a product of the representation of an object,
whether elicited by external or internal stimulation.
So-called canonical neurons (found in parietal-premotor
cortical circuits of monkey) respond both to an action and
to the visual properties of an object (Di Pellegrino, Fadiga,
Fogassi, Gallese, & Rizzolatti, 1992; Rizzolatti, Fadiga,
Fogassi, & Gallese, 1996). Generally, the action they code
and the objects they respond to are congruent, for instance
the grip type used to handle the object. It seems plausible
that the analogue of this system in humans is involved in
micro-affordance effects. In contrast to canonical neurons,
mirror neurons (also found in the parietal-premotor cortical
R. Ellis (&) � D. Swabey � J. Bridgeman � B. May �M. Tucker � A. Hyne
School of Psychology, University of Plymouth,
Drake Circus, Plymouth PL4 7AA, UK
e-mail: [email protected]
123
Psychological Research (2013) 77:31–39
DOI 10.1007/s00426-011-0391-y
![Page 2: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/2.jpg)
circuits of monkey) fire when actions are executed by the
individual, and upon observation of the same action exe-
cuted by another agent (Di Pellegrino et al., 1992; Gallese,
Fadiga, Fogassi, & Rizzolatti, 1996; Rizzolatti et al., 1996).
The existence of a human mirror system seems likely given
similar observation and execution activation effects infer-
red from transcranial magnetic simulation data (Hari et al.,
1998) and brain imaging (Gazzola & Keysers, 2009).
Actual measures of single cell responses in humans,
undergoing surgery to treat severe epilepsy, confirm the
existence of neurones responding to both the execution and
observation of particular grips (Mukamel, Ekstrom, Kap-
lan, Iacoboni, & Fried, 2010).
The human mirror system is thought to account for
behavioural imitation effects. For instance, Brass, Bek-
kering, Wohlschlager, and Prinz (2000) demonstrated that
observing an action (finger movements) facilitated a
response consisting of the same action even when the
observed action was an irrelevant stimulus property. Sim-
ilarly, Edwards, Humphreys, and Castiello (2003) showed
that observing prehension-facilitated compatible actions on
an object by the observer. Importantly for what follows,
there is evidence that the human mirror neurone system
includes responses that represent complementary actions.
In an fMRI study, participants observed an agent grasping
an object with either a precision or power grip, and then
prepared either an imitative or complementary response
(Newman-Norlund, van Schie, van Zuijlen, & Bekkering,
2007). Activation, as measured by the BOLD response,
was greater for the complementary cases.
Clearly, the properties of the mirror system suggest a
profound role for it in the coordination of intentional
behaviours among agents. It is commonly seen as under-
pinning our understanding of the actions and intentions of
others, allowing us to predict their behaviour and, there-
fore, successfully engage in joint actions with them (Riz-
zolatti & Craighero, 2004). A decision to cooperate or
compete with others might be expected to condition how
the mirror system influences our responses. Sebanz,
Knoblich, Prinz, and Wascher (2006) demonstrated affects
on event-related potentials that they argue show that indi-
viduals acting together form shared action representations.
Ocampo and Kritikos (2010) describe how instructions to
imitate or produce an action complementary to one
observed in a video, elicits imitative or complementary
effects, respectively, when participants are required, in
catch trials, to simply perform either a precision or power
grip (irrespective of the type of grip they observe in the
video).
Our concerns in this paper are somewhat different to any
of these preceding studies, having two key differences.
First, we aim to investigate the interaction of canonical and
mirror neurone systems, rather than examine their
independent influences on behaviour. For the most part,
they are considered to be different in kind, but we will
attempt to show that there is a case for regarding them as
different aspects of a common system for orchestrating the
actions of agents within their material culture. The second
difference, with the preceding studies, is that our proce-
dures are designed to assess the implicit effects on
responses of observed actions and the actions associated
with seen objects when both are irrelevant to the response.
In summary, we are interested in how the mirror neurone
system and the canonical neurone system interact when we
observe other agents acting on objects, irrespective of our
goals. So, for instance are micro-affordance effects mod-
ulated when another agent acts on a seen object? Does the
mere observation of another agent’s actions on an object
produce imitative or complementary action effects analo-
gous to the effects objects have on their observers? It is our
conjecture that mirror and canonical neural systems have
their primary role in coordinating the actions on objects by
agents. That is, they are part of a dynamic system in which
the actions of other agents and objects in a scene together
and simultaneously determine the actions afforded to an
observer. We presume that intentional mechanisms act to
harness or inhibit these afforded actions so that actual
behaviour is consistent with an agent’s current goals. To be
clear, we are interested in the implicit effects of other
agents and objects in combination.
So, the objects afford the actions associated with them in
human observers; actions performed by humans elicit those
same or complementary actions in other humans seeing
them. How are these two phenomena related? Some
behavioural studies have shown interactions between
affordance and imitation. Bach, Bayliss, and Tipper (2010)
showed that stimulus–response compatibility effects on
making a left or right responses in classifying the grip
aperture of a left or right moving arm were only significant
when the observed grip was congruent with an incidental
goal object. Vainio, Symes, Ellis, Tucker, and Ottoboni
(2008) had participants view an animation of a hand
making a power or precision grip, before classifying
objects compatible with a precision or power grip grasp, by
themselves making a precision or power grip. The usual
object by response compatibility effect was observed, but
only when the observed grip was congruent with the object.
Clearly, imitation and affordance effects may be mutually
constraining, and we now describe two experiments that
examine the effects of observing actual reaches towards a
goal object so as to better understand what we will call the
‘dialectical relations’ between agents and their material
culture.
When another person reaches toward an object our
attention will often be drawn to that object. Given we have
noticed both the action of the other agent and the object
32 Psychological Research (2013) 77:31–39
123
![Page 3: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/3.jpg)
they are reaching toward, how do the affordance and mirror
systems jointly affect our responses? In an initial study, our
participants were shown a video of a left or right-handed
reach, from the participant’s perspective, toward an object.
The hand movement was tracked and the object only came
into view towards the end of the observed reach. The task
of the participant was to classify the object using a right or
left-hand key-press. The object was orientated so as to be
optimally graspable with a left or right hand. Which of the
various action-related properties of these scenes affect
responses? Does the object orientation facilitate responses
with a congruent hand? Does the hand of reach depicted in
the video produce imitation effects? Or might comple-
mentary action effects be observed, such that observing a
reach toward the handle side of an object facilitates a
response with the hand that would be optimal for reaching
to the non-handle side?
Experiment 1
Method
Participants
All the 33 participants were students at the University of
Plymouth and they received course credit for participating.
All were right-handed by self-report and had normal or
corrected to normal vision. Informed consent was obtained
from each participant prior to commencing the task.
Apparatus and materials
Video clips were presented on a LCD screen approximately
50 cm distant from the participant. Stimulus presentation
was controlled by Eprime 2.0 and responses collected on an
Eprime button box.
The stimuli consisted of 112 clips of reaches toward
common objects. Each clip started with a view of a pair of
arms and hands resting on a table, viewed from above and
immediately behind (approximating therefore to the par-
ticipants’ perspective on the scene). One of the hands
reached forward in space, and the camera tracked this
movement. Each clip was edited such that the object first
came into view in frame number 82 of each clip (just over
3 s from the start), and each lasted a total of 5 s. The clip
ended with the hand located either at the handle or non-
handle side of the object, and before the shaping of the
hand for an actual grasp. There were 28 objects (named in
the Appendix) in the clips, half were kitchen implements
and half were tools. Each was filmed four times with all
combinations of left or right reaches to left- or right-ori-
entated objects. Figure 1 shows the start and end frame
from a typical case.
Procedure
After ten practice trials, there were 112 experimental ones.
Participants were told to response as quickly as possible
with a left-hand button press if they saw a kitchen object,
and a right-hand button press if they say a tool. There was a
Fig. 1 The start and end frames
of a video clip used in
experiment one (upper panels);
and in experiment two (lowerpanels)
Psychological Research (2013) 77:31–39 33
123
![Page 4: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/4.jpg)
blank screen for 500 ms between each trial, and at the end
of the video the screen displayed the final frame until the
participant responded or was timed out after 2 s.
Results
Response times
The response latency data were filtered for outliers, for
each participant, by removing responses plus or minus two
standard deviations from the mean. The remaining data
were analysed in a three-factor, within-subjects analysis of
variance, with object orientation, hand of reach of the
actor, and hand of response of the participant as the factors.
There was one significant main effect. Left-handed
responses were faster (M = 784 ms) than right-handed
(M = 798 ms), F(1,31) = 4.91, p = 0.034. This latter
difference, we assume, merely reflects the greater ease in
classifying a kitchen implement compared to a tool.
The theoretically important interaction of object orien-
tation by hand of response was significant, F(1,31) = 5.30,
p = 0.028, suggesting that object affordance was an
influence on responses. This took the form of a typical
object to object orientation compatibility effect; with
congruent cases, 12 ms faster than incongruent trials. Also
significant was the interaction of object orientation by hand
of reach of the actor, F(1,31) = 4.24, p = 0.048, sug-
gesting that the observed actions of the actor influenced
response too. Again, this took the form of a compatibility
effect; with congruent reaches, 18 ms faster than incon-
gruent trials. Critically, the actor reach effects are not
simply spatial, Simon-like, effects, as revealed by the
significant interaction of response by actor reach,
F(1,31) = 37.47, p \ 0.0005. In fact, responses were
39 ms slower whenever the hand of response and hand of
reach were the same.
There was a significant and striking three-way interac-
tion of object by reach and response, F(1,31) = 362.68,
p \ 0.0005, i.e. illustrated in Fig. 3. There appears to be
huge negative response to object orientation compatibility
effects whenever the actor reaches with their left hand
(congruent trials are 73 ms slower), and equally large
positive effects when they reach with their right hand
(congruent trials are 97 ms faster).
Error rates
Mean error counts were subject to a similar analysis. This
indicated main effects of object orientation (responses to
left-orientated objects were more accurate (M = 0.76) than
to right-orientated (M = 0.96), F(1,31) = 6.02, p = 0.020)
and the reach of the actor (responses on left reach trials were
more accurate (M = 0.71) than to right-orientated
(M = 1.01), F(1,31) = 18.20, p \ 0.0005).
The interaction of hand of response by object orientation
was significant, F(1,31) = 15.95, p \ 0.0005, but, unlike
the effect in reaction times, was a negative compatibility,
with congruent cases producing more errors (M = 1.06)
than incongruent ones (M = 0.67). The interaction of
object orientation by hand of reach of the actor was sig-
nificant, F(1,31) = 6.06, p = 0.020, and was also not
entirely consistent with the reaction time effect. That is,
although congruent reaches to left-orientated objects pro-
duced fewer errors than incongruent (M = 0.70 and 0.81,
respectively), the reverse was true for responses to right-
orientated objects (M = 1.20 and 0.72 for the congruent
and incongruent cases). The interaction of response by
actor reach was not significant, F(1,31) = 2.01,
p = 0.157), but, importantly, the trend was consistent with
the reaction time data, there being more errors when the
actor’s and participant’s reach was similar compared to
dissimilar (M = 0.95 and 0.78, respectively).
The three-way interaction of object by reach by response
is again significant, F(1,31) = 3.06, p = 0.003, but
appears to be driven by differential error rate for the
required responses for the two reaches. That is when a left
hand reach is viewed, more errors are made in the case of
what should be left-hand responses compared to the right-
hand response trials (M = 0.92 and 0.50, respectively),
suggesting that viewing a left-hand reach tends to elicit a
right-hand response in the participant. For right-hand reach
trials, there is little difference (the corresponding means
being 1.04 and 0.97). In both cases of reach, there is a
negative compatibility of hand of response by object ori-
entation, which contrasts, of course, with the reaction time
data. In the latter, a negative compatibility effect was found
for the left-hand reach trials and a positive compatibility
for the right-hand cases.
A summary of the error data can be inspected in
Table 1.
Table 1 Mean error scores in experiment one
Object
orientation
Reach of
actor
Response of
participant
Mean
error
Left Left Left 1.00
Right 0.40
Right Left 1.15
Right 0.47
Right Left Left 0.84
Right 0.59
Right Left 0.94
Right 1.47
34 Psychological Research (2013) 77:31–39
123
![Page 5: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/5.jpg)
Normalised reaction times
Given the various inconsistencies in the two data sets, a
further, similar analysis was conducted on a single data set
derived by dividing the reaction times by the proportion of
correct responses (Townsend & Ashby, 1978).
There were just two significant effects. The interaction
of hand of participant response by the observed hand of
reach, F(1,31) = 18.04, p \ 0.0005, confirms the perfor-
mance benefit for responding with the opposite hand
to that in the observed reach. The three-way interaction
of object compatibility by reach by response,
F(1,31) = 129.01, p \ 0.0005, also confirmed the effect
of the hand of the observed reach on the object compat-
ibility effect, with left-hand reaches associated with neg-
ative compatibility and right-hand reaches associated with
a typical positive compatibility effect. These interactions
in the normalised reaction time data are illustrated in
Fig. 2.
Discussion
To summarise this data set: (1) the reach of the actor did
produce overall effects on the responses, it being easier to
respond with the hand opposite to that of the observed
reach and (2) the actions associated with the object also
effected responses, but these were modulated by the
observed reach, with a negative compatibility effect when
observing a left-hand reach, compared to a positive com-
patibility effect when observing a right-hand reach. It is
worth reminding oneself that neither the reach of the actor
nor the action properties of the object are relevant to the
goal of the participants.
The influence on responses of the reach of the actor
was not a simple imitation or spatial congruency effect; it
could be interpreted as a complementary action effect.
That is, it was generally easier for the participants to
respond with the opposite hand to the observed reach,
suggesting the potentiation of a reach towards the part
that was not to be occupied by the end state of the actor’s
reach. The observation of an actor’s reach also strongly
affected the relationship between the participant’s
response and the orientation of the object, a reliable
negative compatibility effect being observed with left-
hand reaches and the reverse when a right-hand reached
was seen.
The modulation of the object to action compatibility
effect by the hand of reach could be regarded as a conse-
quence of the hand observed or the visual field in which the
hand reaches from, given the two are confounded. The next
experiment seeks to identify which is the case by simply
having the actor depicted reaching from a position opposite
to the participant.
Fig. 2 The interaction, in experiment 1, of the hand of response of
the participant and the hand of the actors reach (top figure) and the
three-way interaction of object orientation by hand of response by
actor’s reach (bottom two figures)
Psychological Research (2013) 77:31–39 35
123
![Page 6: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/6.jpg)
Experiment 2
Method
Participants
All the 30 participants were students at the University of
Plymouth and they received course credit for participating.
All were right-handed by self-report and had normal or
corrected to normal vision. Informed consent was obtained
from each participant prior to commencing the task.
Apparatus, materials and procedure
These were identical to those in experiment one except the
video clips showed a reach from opposite the participant as
illustrated in Fig. 1.
Results
Response times
One participant’s data were excluded because of a high
error rate. The response latency data for the remainder
were filtered for outliers, for each participant, by removing
responses plus or minus two standard deviations from the
mean. The remaining data were analysed in a three-factor,
within-subjects analysis of variance, with object orienta-
tion,1 hand of reach of the actor, and hand of response of
the participant as the factors.
There were significant main effects of all three factors.
Consistent with the previous experiment, left-handed
responses were faster (M = 716 ms) than right-handed
(M = 828 ms), F(1,28) = 170.85, p \ 0.0005. This dif-
ference is an order of magnitude greater than that observed
in the first experiment however. Also in contrast to the first
experiment, there were main effects of object orientation
and the hand of the actor’s reach. Responses to left-ori-
entated objects were faster (M = 753 ms) than to right-
orientated (M = 791 ms), F(1,28) = 22.92, p \ 0.0005.
Responses to stimuli depicting a left-hand reach by the
actor were faster (M = 762 ms) than the responses to a
right-hand reach (M = 782), F(1,28) = 10.21, p = 0.003.
The interaction of object orientation by hand of response
was significant, F(1,28) = 21.60, p \ 0.0005, and is
broadly similar to that obtained, in non-normalised reaction
times, in the first experiment. Specifically, a left-hand
response to a left-orientated object is 81 ms faster than the
same response to a right-orientated object, whereas the
equivalent difference for the right-handed responses is only
39 ms. Given the main effect of hand of response, this
would suggest an influence of affordance on the right-hand
responses. The interaction of object orientation by reach of
the actor was significant, F(1,28) = 51.68, p \ 0.0005,
and rather more emphatic. It takes the form of a compati-
bility effect, but, given the actor’s perspective reverses the
handle orientation relative to the reach, it is best interpreted
as faster responses (M = 751 ms) whenever the actor’s
hand reached toward the non-handle side of the object
compared to a reach towards the handle (M = 793 ms).
The interaction of hand of response by hand of actor’s
reach was also significant, F(1,28) = 51.68, p \ 0.0005,
which reflects a huge advantage for responding with the
left hand (M = 666 ms) compared to the right
(M = 896 ms) when the actor reached with their right
hand, but little difference when the actor’s reach was with
their left hand.
Finally, the three-way interaction between the factors
was significant, F(1,28) = 11.65, p = 0.002. As in the first
experiment there was a striking difference between the
interactions of object orientation by hand of response for
the different reaches of the actor. There was no interaction
in the case of left-hand reaches, but a typical (positive)
compatibility effect whenever the actor reached with their
right hand.
Error rates
Mean error counts were subject to a similar analysis. There
was single, significant main effect of hand of response,
F(1,28) = 60.85, p \ 0.0005, consisting of more errors for
left-hand responses (M = 1.35) compared to the right hand
(M = 0.33). This is of course the reverse of the perfor-
mance benefit in the reaction time data for left-hand
responses.
Of the interactions, only the three-way object by
response and by reach was significant, F(1,28) = 10.37,
p = 0.003. This had the form of there being negative
compatibility of object orientation by hand of response for
observing left-hand reaches and a positive compatibility for
right-hand reaches.
A summary of the error data can be inspected in
Table 2.
Normalised reaction times
A similar ANOVA was conducted with normalised reac-
tion times to resolve the discrepancies between the two
performance measures and to provide a consistent com-
parison with the data from the first experiment.
There were significant main effects of object compati-
bility, F(1,28) = 16.28, p \ 0.0005, and the participant’s
hand of response, F(1,28) = 12.79, p = 0.001. Faster
1 That is the orientation relative to the participant, which is, of
course, reversed for the actor’s perspective.
36 Psychological Research (2013) 77:31–39
123
![Page 7: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/7.jpg)
responses were observed with left-orientated objects
(M = 802 ms) than those orientated to the right
(M = 843 ms); and left-hand responding was faster
(M = 797 ms) than right (M = 849 ms).
All three two-way interactions were significant, but the
three-way was not. Both the interaction of response hand
by object orientation, F(1,28) = 17.73, p \ 0.0005, and
the interaction of hand of actor’s reach by object orienta-
tion, F(1,28) = 30.09, p \ 0.0005, reflected similar, posi-
tive compatibility effects observed in the reaction time
data. The interaction of hand of response by actor’s reach,
F(1,28) = 202.28, p \ 0.0005, was rather more emphatic
than in the reaction time data alone; for both left and right
hand reaches, it was easier to respond with the opposite
hand. Given these reaches are seen from opposite the
participant it should be noted that a spatial compatibility is
associated with responses with opposing hands. These
interactions are illustrated in Fig. 3.
Discussion
Once again the participants’ responses were influenced by
the observed reach of the actor and the actions afforded by
the object, even though both were irrelevant to their task.
As in the first experiment, responding with the opposite
hand to that of the reach was easier than responding with
the same hand, but the effect was larger, with an average of
129 ms faster responses for the opposite hand, compared to
44 ms in the first experiment.2 One interpretation of this
contrast is that the change from an egocentric to an allo-
centric reach enhanced the complementary action effect
(Bruzzo, Borghi, & Chirlanda, 2008). It is equally plausi-
ble, however, that the difference has its origin in the
additional spatial compatibility that occurs in the second
Fig. 3 The interactions, in experiment 2, object compatibility by the
hand of response of the participant (top) and the depicted hand of
reach of the actor (middle); and the interaction of response by reach
(bottom)
Table 2 Mean error scores in experiment two
Object
orientation
Reach of
actor
Response of
participant
Mean
error
Left Left Left 1.69
Right 0.71
Right Left 1.93
Right 0.39
Right Left Left 1.90
Right 0.54
Right Left 1.44
Right 0.60
2 A difference confirmed by a significant three interaction of response
by reach by experiment, F(1,59) = 29.47, p \ 0.0005, in an
additional analysis.
Psychological Research (2013) 77:31–39 37
123
![Page 8: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/8.jpg)
experiment, opposite hands sharing a left–right location in
the visual field.
The interaction of the reach of the actor and object
orientation is also open to an explanation in terms of
complementary action. That is, whenever the actor is seen
reaching toward the non-handle location on the object, the
participant’s performance was enhanced. On this interpre-
tation, a complementary action is conceived of as the
behavioural possibilities that are afforded jointly by an
object and the constraints that result from another agent
acting on that object.
General discussion
Participants observed another agent reaching to an object,
either from the observer’s point of view or an opposed
perspective. The orientation of the object was such that it
afforded either a left or right reach-to-grasp for the par-
ticipant. Despite the reach and the afforded actions being
entirely irrelevant to their task of classifying the object,
both influenced participants’ responses.
The influences of the observed reach were not simply
imitative as in previous studies (e.g. Brass et al., 2000).
When observing a reach, from either viewpoint, it was
easier to respond with the hand opposite to the reach. When
viewing a reach from opposite, participants found it easier
to respond when the reach was directed at the non-handle
side of the object. Whilst different in kind, both these
effects suggest responses tuned to the relations between an
object and another agent. In the first case, they seem
straightforwardly complementary action effects, in the
second they seem to reflect priority to another agent when
they reach toward the handle. It is important to note that
this facilitation of apparently complementary actions has
occurred in an experimental procedure which does not
direct manipulate participant’s expectations of the collab-
orative nature of the task as has been the case with previous
investigation of complementary action effects (e.g.
Ocampo & Kritikos, 2010). These new data provide a
demonstration of implicit, non-goal related influences of
the actions of other agents which are not merely imitative.
We assume that observing an act of grasping a single object
by another agent entails the (implicit) possibility of
the handing of that object to the observer. The recipient of
the object must necessarily prepare a grasp on a part of the
object not currently occupied by the other agent. Repeated
experience of such exchanges might be expected to adapt
the mirror neurone system, so it responds to complemen-
tary action, as a result of correlated sensorimotor learning
(akin to the mechanisms suggested for the formation of
imitative responses, as described by Gillmeister, Catmur,
Brass, and Heyes, 2008). We suggest that the handing of an
object between agents provides the foundations for more
elaborate and intentional forms of collaboration.
Object affordance effects, as reflected in object orienta-
tion to response compatibilities, were also found, but the
observed hand of reach modulated these. The relationship
was not, therefore, the equivalent of previous studies in
which the congruence between an observed action and an
object determined whether an object to response compati-
bility was obtained (Vainio et al. 2008; Bach et al. 2010).
Here we found that observing a left-hand reach, in both view
points, was associated with a negative object to response
compatibility and observing a right hand was associated with
the more usual positive compatibility.3 We think that this
unexpected and intriguing result may be best understood in
terms of the lateralisation in the brain of components of the
human mirror neurone system (MNS). Data from fMRI
studies of human participants engaged in cooperative tasks
(such as two individuals jointly maintaining the balance of a
virtual beam) indicate that joint activity appears to selec-
tively involve parts of the MNS in the right hemisphere
(Newman-Norlund, Bosga, Meulenbroek, & Bekkering,
2007, 2008). The implication that complementary actions
are lateralised in this way leads us to suggest that the
observation of a left-hand reach tends to elicit responses in
this system more directly or with greater potency than the
case when observing right-hand responses. It has to be
admitted, however, that this is highly speculative and, at this
point, inadequate as an account of the actual behavioural
differences reported here. But it does seem a fruitful starting
point for subsequent investigations.
Our major concern has been to demonstrate interactions
between elements of the motor system that occur when
agents jointly observe and act on objects. Using a simple,
but ecologically plausible, behavioural procedure, we have
shown that even the motor systems of mere observers,
irrespective of their goals, are simultaneously affected by
multiple sources of action possibilities. These influences
are claimed to reflect the interdependency of the action
possibilities that arise from a set of objects and agents in
three-dimensional space that together determine behaviour.
The actual behaviour is the outcome of dynamic and
sometimes conflicting influences from sources such as the
affordance associated with objects, the goals of the agents,
the spatial relations among the agents and objects, the
actions of the agents, and so forth. The actual behaviour of
an agent cannot of course itself be reduced to any of these
parts in particular, and it will also tend to have reciprocal
effects on those parts. Thus, to reach toward an object in a
crowded material and social world is best understood as a
dialectical process.
3 Albeit only in response latency in the case of the point of view
reaches.
38 Psychological Research (2013) 77:31–39
123
![Page 9: Bodies and other visual objects: the dialectics of reaching toward objects](https://reader036.fdocuments.in/reader036/viewer/2022082903/575094cf1a28abbf6bbc4c92/html5/thumbnails/9.jpg)
Appendix
Objects used in the two experiments:
Kitchen implement Tool
Washing-up brush Adjustable spanner
Mug Large saw
Cheese grater Blue hacksaw
Kettle Chisel
Ladle File
Peeler Hammer
Pizza slicer Paintbrush
Spatula Pliers
Sieve Screwdriver
Spoon Spanner
Tin opener Wooden hacksaw
Whisk Wire cutters
Wooden spatula Torch
Wooden spoon Yellow hacksaw
References
Bach, P., Bayliss, A. P., & Tipper, S. P. (2010). The predictive mirror:
interactions of mirror and affordance processes during action
observation. Psychonomic Bulletin Review, 18(1), 171–176.
Brass, M., Bekkering, H., Wohlschlager, A., & Prinz, W. (2000).
Compatibility between observed and executed finger move-
ments: Comparing symbolic, spatial, and imitative cues. Brainand Cognition, 44, 124–143.
Bruzzo, A., Borghi, A. M., & Ghirlanda, S. (2008). Hand-object
interaction in perspective. Neuroscience Letters, 441, 61–65.
Derbyshire, N., Ellis, R., & Tucker, M. (2006). The potentiation of
two components of the reach-to-grasp action during object
categorisation in visual memory. Acta Psychologica, 122, 74–98.
Di Pellegrino, G., Fadiga, L., Fogassi, L., Gallese, V., & Rizzolatti, G.
(1992). Understanding motor events: A neurophysiological
study. Experimental Brain Research, 91(1), 176–180.
Edwards, M. G., Humphreys, G. W., & Castiello, U. (2003). Motor
facilitation following action observation: A behavioural study in
prehensile action. Brain and Cognition, 53, 495–502.
Ellis, R., & Tucker, M. (2000). Micro-affordance: The potentiation of
components of action by seen objects. British Journal ofPsychology, 91, 451–471.
Ellis, R., Tucker, M., Symes, E., & Vainio, L. (2007). Does selecting
one visual object from several require inhibition of the actions
associated with non-selected objects? Journal of ExperimentalPsychology: Human Perception and Performance, 33, 670–691.
Gallese, V., Fadiga, L., Fogassi, L., & Rizzolatti, G. (1996). Action
recognition in the premotor cortex. Brain, 119, 593–609.
Gazzola, V., & Keysers, C. (2009). The observation and execution of
actions share motor and somatosensory voxels in all tested
subjects: single-subject analyses of unsmoothed fMRI data.
Cerebral Cortex, 19, 1239–1255.
Gillmeister, H., Catmur, C., Liepelt, R., Brass, M., & Heyes, C.
(2008). Experience-based priming of body parts: a study of
action imitation. Brain Research, 1217, 157–170.
Hari, S., Forss, S., Avikainen, S., Kirveskari, E., Salenius, S., &
Rizzolatti, G. (1998). Activation of human primary motor cortex
during action observation: a neuromagnetic study. Proceedingsof the National Academy of Science USA, 95, 15061–15065.
Mukamel, R., Ekstrom, A. D., Kaplan, J., Iacoboni, M., & Fried, I.
(2010). Single-neuron responses in humans during execution and
observation of actions. Current Biology, 20, 750–756.
Newman-Norlund, R. D., Bosga, J., Meulenbroek, R. G. L., &
Bekkering, H. (2008). Anatomical substrates of cooperative
joint-action in a continuous motor task: Virtual lifting and
balancing. NeuroImage, 41, 169–177.
Newman-Norlund, R. D., van Schie, H. T., van Zuijlen, A. M. J., &
Bekkering, H. (2007). The mirror neuron system is more active
during complementary compared with imitative action. NatureNeuroscience, 10, 817–818.
Ocampo, B., & Kritikos, A. (2010). Placing actions in context: motor
facilitation following observation of identical and non-identical
manual acts. Experimental Brain Research, 201, 743–751.
Rizzolatti, G., & Craighero, L. (2004). The mirror-neurone system.
Annual Review of Neuroscience, 27, 169–192.
Rizzolatti, G., Fadiga, L., Fogassi, L., & Gallese, V. (1996). Premotor
cortex and the recognition of motor actions. Cognitive BrainResearch, 3, 131–141.
Sebanz, N., Knoblich, G., Prinz, W., & Wascher, E. (2006). Twin
peaks: An ERP study of action planning and control in coacting
individuals. Journal of Cognitive Neuroscience, 18, 859–870.
Townsend, J. T., & Ashby, F. G. (1978). Methods of modelling
capacity in simple processing systems. In N. J. Castellan & F.
Restle (Eds.), Cognitive Theory (pp. 199–239). Hillsdale:
Erlbaum.
Tucker, M., & Ellis, R. (1998). On the relations between seen objects
and components of potential actions. Journal of ExperimentalPsychology: Human Perception and Performance, 24, 830–846.
Tucker, M., & Ellis, R. (2001). Micro-affordance of grasp type in a
visual categorisation task. Visual Cognition, 8(6), 769–800.
Tucker, M., & Ellis, R. (2004). Action priming by briefly presented
objects. Acta Psychologica, 116, 185–203.
Vainio, L., Ellis, R., & Tucker, M. (2007). The role of visual attention
in action priming. Quarterly Journal of Experimental Psychol-ogy, 60, 241–261.
Vainio, L., Symes, E., Ellis, R., Tucker, M., & Ottoboni, G. (2008).
On the relations between action planning, object identification,
and motor representations of observed actions and objects.
Cognition, 108, 444–465.
Psychological Research (2013) 77:31–39 39
123