Journal of Personality and Social Psychology1990, Vol. 58, No. 6.1004-1014

Copyright 1990 by Ihe American Psychological Association, Inc.OO22-3514/90/J0O.75

What Can a Moving Face Tell Us?

Diane S. BerrySouthern Methodist University

This research assessed the impact of facial motion on perceptionsof age-related person qualities. Ssjudged the power of point-light displays of the faces of children, middle-aged adults, and elderlyadults. Ratings were obtained of (a) dynamic displays filmed while the stimulus persons werereciting the alphabet, (b) dynamic displays filmed, while the stimulus persons engaged in an inter-action, and (c) static versions of the displays. Facial age exerted no effect on the perceived power ofnondynamic displays. However, moving displays of children's faces were judged to be less powerfulthan were those of adults. Differences in perceived age could not explain these effects. The implica-tions of these data for the developing area of social event perception are discussed.

Fifty years ago, Heider(1944) recognized the role of percep-tual processes in social knowledge acquisition. In particular, hesuggested that events may provide visual information about theproperties of the persons involved in them, as well as the natureof the event itself: "When we see a person lift a heavy weight, weperceive at the same time that he is strong. 'Lifting a heavyweight' and 'being strong' belong together as manifestation andfaculty, but they can hardly be called similar" (p. 365). Asch(1952) also emphasized the primacy of visual events in socialperception. Asch further proposed that rather than being theend result of an inferential process, the knowledge derived fromexposure to events is specified in the underlying structure ofaction (Newtson, Hairfield, Bloomingdale, & Cutino, 1987). Acolleague of Heider or Asch might have predicted a bright fu-ture for the study of social event perception. However, the cog-nitive revolution in social psychology literally turned the focusof future inquiry inward, emphasizing the development of so-phisticated cognitive models of social knowing (eg., Wyer &Srull, 1986). Although these models have greatly advanced theunderstanding of how humans process social information, theyhave little to reveal regarding the nature of incoming data:Much less attention is paid to what is processed than to how it isprocessed. In fact, the vast majority of research in this areamakes use of semantic input, although most experiences ofother persons are surely made up of light, motion, sound, andtouch.

Despite this reluctance to consider whether knowledge about

This article is based on a doctoral dissertation submitted to BrandeisUniversity, and was supported by a dissertation research award fromthe Department of Psychology. Some of the data were presented at theFourth International Conference on Event Perception and Action,Trieste, Italy, August 1987.

I would like to thank Leslie Zebrowitz-McArthur for her advice andsupport during all phases of this work. I am also grateful to Joe Cun-ningham, Rebecca Eder, Judith Hall, Margie Lachman, Jamie Penne-baker, Harry Reis, and Jim Todd for their thoughtful suggestions onthis research.

Correspondence concerning this article should be addressed toDiane S. Berry, Department of Psychology, Southern Methodist Uni-versity, Dallas, Texas 75275-0442.

other people may be perceptually specified, some researchershave studied the person information revealed in visual events.Much of this work has expanded on Johansson's (1973) demon-stration that human movement can be readily identified from adynamic configuration of point-light sources attached to awalker's major joints. For example, Cutting and his associates(e.g., Cutting & Kozlowski, 1977; Kozlowski & Cutting, 1977)demonstrated that knowledge about gender and personal iden-tity is available in point-light gait displays. Montepare and Ze-browitz-McArthur (1988) reported that information regardingrelative age is also extracted from parameters of human gait.Further evidence of the richness of the information provided inhuman action is provided by Runeson and Frykholiris (1981,1983) demonstration that perceivers can make accurate judg-ments of effort and deception from point-light displays of aperson's movements.

The human face is also an important source of dynamic in-formation. Faces continually undergo complex patterns of ra-pid deformation and more gradual transformations such asgrowing and gaining or losing weight. Moreover, they consti-tute rich sources of person knowledge. People readily extractinformation from faces about qualities such as personal identity(e.g, Ellis, Shepherd, & Davies, I979), gender (Berry, 1990), age(eg., Mark, Todd, & Shaw, 1981), and emotional state (cf. Ek-man, Friesen, & Ellsworth, 1982). Moreover, particular dispo-sitional characteristics are rapidly and reliably ascribed to par-ticular faces (eg., Berry & McArthur, 1986).

With few exceptions, the stimulus information on whichthese perceptions are based is not well understood. In particu-lar, researchers who have restricted their study of faces to thestatic visual patterns to which they give rise have met withlimited success in identifying or explaining the complex pat-terns of stimulation that result in particular perceptions (cf.Bruce & Green, 1985). An alternative is to conceptualize facialinformation as involving the visual specification of facialchanges or events (e.g., Berry, in press). As previously men-tioned, faces are subject to a variety of transformations. Underwhat circumstances will these changes provide person infor-mation? At minimum, it would seem necessary for an event toshare an invariant relation with some person quality to reveal

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that quality. For example, we would not expect the facialchanges associated with yawning to provide age information, asage does not constrain this action. However, we would predictthat the styles of facial change associated with aging will com-municate knowledge about age, as a particular craniofacialtransformation is indeed produced by growth.

Aging has been a widely studied facial event.1 In particular,Shaw and his associates have suggested that the abstract style ofchange that faces undergo as a function of growth provides aninformational basis for age perception (e.g Shaw & Pittenger,1977; Todd, Mark, Shaw, & Pittenger, 1980). One reason forperceivers' keen sensitivity to this information is thought to bethe adaptive significance of the recognition of maturationalstatus. Extending this line of reasoning, it has been proposedthat person qualities that are both correlated with chronologi-cal age and vital to detect may also be revealed by visible mor-phological consequences of growth. Age-related differences inrelative naivete, helplessness, dependency, and strength are espe-cially important to recognize. Thus, it has been posited thatinformation about differences in physical power and in socialpower that are linked to chronological age will be available inthe perceptible stimulus qualities that are correlated with age.Support for this hypothesis is provided by research demonstrat-ing that variations in facial appearance produced by the slowevent of facial growth provide an informational basis for theperception of these person qualities (e.g Alley, 1983; Berry &McArthur,1986).

Slow facial changes associated with age thus produce config-ural diiferences in faces of different ages that reveal age-relatedcharacteristics. The intent of the present research is to assesswhether rapid facial changes also share an invariant relationwith development and communicate age and age-related per-son qualities. Although little is known about the specific natureof age-dependent changes in facial motion, there is evidencethat such differences exist. For example, there is considerabledocumentation of age-related changes in emotional expression.Much of these data focus on early developmental differences inproduction ability (e.g., Field & Walden, 1982; Odom & Le-mond, 1972) or the use of facial display rules (e.g., Cole, 1986;Malatesta & Haviland, 1982). Furthermore, Malatesta andIzard (1984) have reported age-related differences in the facialbehaviors of young, middle-aged and older adults. These dataindicate age-related changes in discrete facial behaviors. In ad-dition, growth-determined differences in facial anatomy mayhave an impact on the overall style of movement that character-izes faces of different ages. Such a general invariant could alsoinfluence perceptions of age-related person qualities.

Because patterns of facial motion appear to covary with age,and because the detection of person qualities that covary withage serves an adaptive function (cf. Alley, 1986; Berry &McArthur, 1986), it was predicted that age-dependent varia-tions in facial movement would provide perceivers with infor-mation about age-related differences in the physical, social, andintellectual power of stimulus persons. This focus on the role offacial motion in the perception of faces dictated that movingfaces should be used as stimuli. However, standard videotapesof moving faces provide to perceivers information about facialconfiguration as well as facial motion. Previous research clearlyreveals that configural facial qualities exert a strong and reliable

impact on the perception of faces (e.g., Berry & McArthur,1986). Therefore, it is not possible to assess the independentcontribution of facial movement to impressions when displaysthat confound both forms of information are viewed. This ex-periment used a methodology that circumvents this problem.This technique involves filming a moving object to which smalllight sources are attached. Films are then presented on a moni-tor that is adjusted so that a display appears as a configurationof points against a dark background. The advantage of thispoint-light technique is that it highlights dynamic informationwhile concealing information about an object^ appearance andstructure.

Subjects' perceptions of the power of point-light displays ofthe faces of children, middle-aged adults, and older adults wereassessed. It was predicted that moving displays of children'sfaces would be perceived to be less powerful than would thoseof adults. The point-light technique was specifically used be-cause it highlights dynamic facial information and degradesinformation about facial appearance and structure. However,there are several nondynamic sources of information that couldconceivably be retained in these displays and could provideinformation to perceivers. For example, the relative size of theforehead and chin varies as a function of facial age (e.g., Mark &Todd, 1983). Information about differences in the relative areasof such regions of the faces could also be provided in thesedisplays. Still and moving displays were therefore created toensure that such differences were not the basis of judgmentsmade about the faces. As such nondynamic qualities would beavailable in both the moving and still displays, differences inperceptions of these faces can be attributed to the dynamicinformation only available in the moving displays. Two ver-sions of dynamic displays were also prepared. In particular,faces were filmed while reciting the alphabet and while inter-acting. These displays were obtained to gain insight into thenature of the information underlying any observed effects offacial motion on the perception of age-related person qualities.One possibility is that some age-related differences in the un-derlying structure of faces produce concomitant differences inoverall facial dynamics. Such a general invariant should be re-vealed in nonsocially as well as in socially elicited facial mo-tion. Given this, age of face would exert an impact on the per-ceived power of reciting as well as interacting faces. Alterna-tively, the effects of facial age could be based on differences insocially elicited patterns of facial motion that characterize facesof different ages. If this were the case, age of face would beexpected to influence the perceived power of interacting butnot reciting faces.

The premise of this research is that age-variant patterns of

1 The term event may seem an unusual connotation for changes, suchas facial aging, that occur over a period of years and that are not phe-nomenologically experienced as motion. However, in this literature,the definition of event incorporates any change over time, regardless ofits temporal duration. The inclusion of such slow changes under therubric of event is more than a semantic distinction, as it has implica-tions for the processes posited to be involved in the detection of infor-mation from such changes. This point is beyond the scope of this arti-cle, and interested readers are referred to Mace (1985) and Shaw andPittenger (1978) for an extended discussion.

1006 DIANE & BERRY

facial motion will provide perceivers with knowledge aboutage-related differences in power. An alternative explanation ofany observed age-related differences in perceived power is thatfacial motion provides information about chronological age, onwhich perceivers base their power judgments. In addition, thereis some evidence that faces exhibiting immature facial qualitiesare perceived to be more feminine than are more seeminglymature faces(Berry, 1990; McArthur& Berry, 1986). Judgmentsof the perceived age and femininity of the faces were thereforeobtained to ensure that age-related differences in perceivedpower could not be accounted for by differences in the per-ceived age or femininity of the faces.

Method

Stimulus Displays

The videotaped stimulus displays used involved a modification ofJohansson's (1973) point-light procedure. This technique was adaptedby Bassili (1978,1979) for use with moving faces. The displays were

prepared by affixing 100 circular patches of light-refiectant material tothe stimulus faces. The patches were approximately 0.5 cm in diameterand were evenly distributed over the face. Illumination was providedby a spotlight mounted close to the video camera lens and aimed to-ward the ceiling. This indirect light resulted in limited illumination ofthe uncovered skin area but was sufficient to illuminate the light-re-flectant material. Using a zoom lens, the size of each face was adjustedto a standard height of 8 in. on a I5-in. monitor. The faces were thenvideotaped against a black background. Displays were recorded onto'/z-in. videotapes via a JVC video recorder and a Sony video camera.When viewed on a black and white monitor on which the brightness isminimized and the contrast maximized, the displays appeared as aconfiguration of white dots against a black background.

Stimulus persons. Twenty-four stimulus persons' faces were video-taped for use in the study as follows: These 4 female children (Mage =5.2 years), 4 male children (M age = 5.7 years), 4 female middle-agedadults (Aif age = 35.6 years), 4 male middle-aged adults (Mage = 36.9years), 4 female older adults (M age = 70.1 years), and 4 male olderadults (M age = 71.5 years).

Videotaping procedure. Still displays of the faces were filmed first,and the alphabet recitations were filmed second. The stimulus personswere asked to hold their heads still and to look directly into the camerawhile they were filmed. The social interaction was filmed last. Two of

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Figure 1. Perceived power as a function of age of stimulus face for static and dynamic facial displays.

MOVING FACES 1007

the four stimulus persons of a given age and gender combination (e.g.,male older adults) interacted with a female research assistant in herearly twenties. The remaining two stimulus persons (targets) of a givenage and gender group interacted with a male research assistant of thesame age. The research assistant sat approximately 4 ft from the target,directly in front of the video camera. Adult targets were asked to dis-cuss an aspect of their work that they especially enjoyed. Childrenwere asked to talk about activities that they were involved in at schooland that they particularly liked. To increase the naturalness of theseinteractions, the conversation was surreptitiously filmed. To this end,the stimulus person and the assistant were left alone and were in-structed to spend several minutes talking before the filming began.The camera had in fact been turned on at the time the assistant enteredthe room. The stimulus persons ultimately included in this study indi-cated that they had not been aware that they were being filmed duringthe conversation.

Original master videotapes of the stimulus faces were edited to pro-duce the tapes eventually viewed by the subjects. All stimulus tapesconsisted of a series of 30-s clips of facial displays separated by 10-spauses. Segments of the reciting faces were selected at random. Seg-ments of the interacting faces were selected so that the target personwas speaking for the duration of the clip.

Manipulation check: Perceptions of static displays. If static versions

of point-light faces of children and adults were perceived to differ inpower, one could not be sure whether parallel differences in percep-tions of moving displays were due to patterns of facial movement or toaspects of facial structure that differentiate the faces of children andadults and were retained in the displays. Thus, before assessing theimpact of movement on perceptions of the displays, it was necessary toensure that structural facial information retained in the displays hadindeed been degraded to the point that it could not reveal differencesin power related to chronological age. To assess this, 12 male and 12female undergraduates provided ratings of static displays of the point-light faces. Equal numbers of men and women were randomly assignedto view one of two orders of stimulus presentation. Subjects were testedin groups of two to four. They were told that they would be asked tojudge a series of stimulus faces on several dimensions. The generalprocedure for creating a point-light display was described, but no in-formation was provided concerning the use of such displays.

Subjects viewed the stimulus faces from a distance of 4-6 ft, on aproperly adjusted black and white video monitor. Displays were pre-sented in 30-s clips. Subsequent to each display, subjects were given 10 sto complete dependent measures. The point-light faces were presentedtwice. During the first presentation, they were rated on four 9-point,bipolar scales that reflect physical, social, and intellectual power.These had endpoints of physically weak - physically strong, submis-

CHILD MIDDLE ADULT OLDER ADULTAGE OF STIMULUS FACE

Figure 2. Perceived age as a function of age of stimulus face for static and dynamic facial displays.

1008 DIANE S. BERRY

sive-dominant, vulnerable-invulnerable, and naive-worldly. These ap-peared in one of three random orders. During the second presentation,subjects indicated the age of the stimulus faces on a 9-point scale thatincorporated age estimates ranging from 5 years to 85 years in 10-yearincrements, and rated each face on a 9-point scale with endpoints ofmasculine-feminine. Order of completion of the age and femininityscales was counterbalanced across subjects.

The average intercorrelation of the four power ratings was .79. Thus,the scales were combined to create a composite variable. Specifically,the mean rating received by a given face from a given subject on each ofthe scales was computed. Analyses of this composite variable werethen performed- These are reported here and throughout the article.

Subjects' perceptions of the power of still facial displays were ana-lyzed in 2 X 3 X 2 (Sex of Subject X Chronological Age of Face X Sex ofFace) analyses of variance (ANOVA) with repeated measures on the lattertwo variables. Analyses of age and femininity ratings are discussedlater. These analyses revealed that age of face did not influence percep-tions of the power of still point-light faces, F{2, 44) < 1, ns. Thus, stillfaces of children, middle-aged adults, and older adults were not per-ceived to differ in power. This indicated that the configural informa-tion previously revealed to communicate age-related person qualitieswas not available in the still point-light faces. Having established this,judgments of dynamic versions of the faces were obtained.

Perceptions of Dynamic Displays

Subjects. Forty-eight male and 48 female undergraduates vieweddynamic displays of the poi nt-iight faces. Equal numbers of male andfemale subjects were randomly assigned to view both reciting and in-teracting versions of one of four subsets of the stimulus persons, one oftwo random orders of stimulus-face presentation, one of three orders ofthe power judgments, and one of two orders of the continuous age andgender scales.

Procedure. The procedure was similar to that described earlier.

Results

Perceptions of Static Versus Dynamic Faces

Perceived power. A primary question of interest in thisstudy was whether age-related differences in power are revealedby patterns of facial motion. In particular, it was predicted thatadults' facial movements would produce impressions of greaterpower than would those of children. Previous research has re-vealed that variations in age-related configural qualities of theface influence such judgments (Berry & McArthur, 1986).

CHILD MIDDLE ADULT OLDER ADULTAGE OF STIMULU8 FACE

Figure 3. Perceived femininity as a function of age of stimulus face for static and dynamic facial displays.

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Figure 4. Perceived power as a function of age of stimulus face for reciting and interacting faces.

Thus, it was important to ensure that any observed differencesin perceptions of power were not based on structural informa-tion retained in the moving displays. The previously reportedanalysis of impressions of the still faces had revealed no relationbetween age of face and perceived power. Further analyses wereconducted to directly compare perceptions of the still and dy-namic facial displays. Specifically, a 2 x 2 X 2 x 3 (Static vs.Moving Display x Subject Sex X Sex of Face x ChronologicalAge of Face) ANOVA with repeated measures on the latter twovariables was performed on judgments of power.

Results revealed a significant main effect of age of face, F(2,232) = 13.13, p ^ .001, and a significant interaction of age anddisplay type, F(2,232) -11.68, p .001. Simple effects analysesconducted within display type revealed that, as predicted, chro-nological age exerted an impact on the perceived power of mov-ing faces, F{2,188) = 56.79, p <= .001, but had no impact onimpressions of still faces, F(2, 44) - <1, ns. As can be seen inFigure 1, moving middle-aged adult faces and older adult faceswere both judged to be more powerful than childrens' faces,Bonferroni te(95) = 7.78 and 9.59, respectively, ps <= .05;whereas middle-aged and older adult faces did not differ in

perceived power, /(95) = 1.35, ns. A main effect of display typewas also revealed, F{\, 116) = 5.30, p <• .05. This reflected thefact that moving faces were rated as more powerful than werestatic facial displays.

Consistent with predictions, childrens' moving faces wereperceived to be less powerful than adult faces. Because age didnot affect the perceived power of static displays, these effectscannot be attributed to structural information retained in thepoint-light faces.

Perceived age and femininity. One possible explanation ofthese data is that age or gender-related knowledge is communi-cated by patterns of facial motion and thus provides the basisfor age-related variations in perceptions of power. To examinethis issue, judgments of the faces' age and femininity were ana-lyzed in separate 2 x 2 x 2 x 3 (Static vs. Moving Display XSubject Sex X Sex of Face X Chronological Age of Face) ANOVASwith repeated measures on the last two variables.

Analyses of the age judgments revealed a significant maineffect of chronological age, F(2, 232) = 65.35, p < .001, and asignificant interaction of age of face and display type, F(2,232)= 18.99, p ^ . 0 0 1 . Simple effects analyses were performed

1010 DIANE S. BERRY

within each display type. Age of face exerted a significant im-pact on the perceived age of still faces, F(2,44) = 5.27, p < .01,and moving faces, F(2,188) = 187.92, p <; .001. As can be seenin Figure 2, chronological age exerted a stronger impact on theperceived age of moving faces than of static faces. However, itshould be noted that faces at all age levels were thought tobelong to adults. Thus, although facial motion can convey in-formation about age, this appears to be limited to knowledgeregarding relative age. This is consistent with the findings ofresearch assessing perceivers' ability to recognize age frompoint-light gait displays (Montepare & Zebrowitz-McArthur,1988).

Analyses of femininity ratings also revealed a main effect ofage, F(2, 232) = 14.72, p<. 001, and a significant interaction ofage and display type, F(2, 232) = 5.30, p ^ .01. Simple effectsanalyses within each display type revealed that chronologicalage exerted no reliable impact on the judged femininity of staticfaces, F(2,44) = 1.81, ns. The perceived femininity of dynamicfaces did vary as a function of age, (2,188) = 41.37, p ^ .001.As can be seen in Figure 3, children's faces were judged to bemore feminine than were either middle-aged or older adult

faces, Bonferroni ft(95) = 5.42 and 10.20, respectively, ps£ .05.Middle-aged adult faces were also rated as more feminine thanwere older adult faces, t(95) = 3.22, p <. .05.

These analyses further revealed an effect of sex of face onperceived femininity, F(\, 116) = 31.80, p <. .001. This was quali-fied by a Sex of Face X Display Type interaction, F(l, 116) =11.87, p ^ .001. Analyses within each display type revealed asignificant effect of sex of face for static faces, F(l, 22) = 10.49,p < .01, and for moving faces, F{\, 94) = 85.92, p <z .001. How-ever, male static faces were perceived to be more feminine thanwere static female faces (Ms = 5.16 and 4.74, respectively),whereas moving male faces were judged to be less femininethan were female moving faces (Ms = 3.75 and 5.46). Althoughgender recognition and judgments of femininity are not oneand the same, these data are consistent with work that has re-vealed that people are more accurate when judging the sex ofmoving faces than of still point-light faces (Berry, 1990).

Covariance analyses. Chronological age does exert an im-pact on the perceived age and femininity of moving facial dis-plays. Can these variables account for the impact of age onperceived power? To address this question, analyses parallel to

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Figure 5. Perceived age as a function of age of stimulus face for reciting and interacting faces.

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Figure 6. Perceived femininity as a function of age of stimulus face for reciting and interacting faces.

those previously reported in which perceived age and feminin-ity were used as covariates were performed. The pattern of re-sults replicated that previously reported. In particular, both themain effect of age, F(2,230) = 11.87, p <, .001, and the interac-tion of age and display type, F(2, 230) = 11.38, p < .001, re-tained significance. Analyses within display type again re-vealed that chronological age of face exerted an impact on theperceived power of moving faces, F{2,186) = 49.67, p < .001,but not still faces, F(2,42) < 1, ns.

In sum, patternsof facial motion do reveal information aboutage-related person qualities. Moreover, although facial motionmay further communicate age and gender-related knowledge,this does not account for the impact of age-variant dynamicinformation on perception of faces' power.

Perceptions of Reciting Versus Interacting Faces

Perceptions of power. Patterns of facial motion communi-cate veridical differences in the power of persons of differentages. What is the nature of the movement information thatgives rise to these perceptions? Analyses of the data obtained

from subjects who viewed moving facial displays were con-ducted to address this question. As discussed previously, if age-related perceptions of power are based solely on socially elicitedpatterns of facial expression, age of face would be expected toinfluence the perceived power of interacting but not recitingfaces. Alternatively, if age-graded skeletal or muscular differ-ences in faces underlie the variations in movement on whichthese judgments are based, age of face should influence therated power of reciting and interacting faces. To examine thisquestion, 2 x 2 x 2 x 3 (Subject Sex X Reciting vs. InteractingFaces X Sex of Face X Age of Face) analyses with repeated mea-sures on the last three variables were performed on perceptionsof power. This revealed that the previously reported main effectof age efface interacted with motion condition, JF(2, 188) =4.45, p < .05. Analyses performed within each motion condi-tion revealed that chronological age exerted a reliable impacton the judged power of both reciting faces, F(2,188) = 23.89,p < .001, and interacting faces, F(2,188) = 58.31, p s .001. Inparticular, both reciting and interacting children's faces werejudged to be less powerful than were middle-aged adult faces,Bonferroni /s(95) = 4.88 and 8.29, ps < .05, and older adult

1012 DIANE S. BERRY

faces ts(95) = 6.65 and 8.47, ps ^ .05. Middle-aged and olderadult faces were not rated differently in either the reciting orinteracting condition, /s(95) = 1.50 and 0.48, ns (see Figure 4).

Although the power attributed to the faces of children andolder adults did not vary as a function of motion condition,middle-aged adult faces were judged to be more powerful wheninteracting than when reciting, Bonferroni /(95) = 4.68, p < .05.

Perceived age and femininity. Analyses of the perceived ageof the faces revealed a significant main effect of motion condi-tion, F{\, 94)— 16.40, p s .001. Reciting faces were, on average,judged to be older than were interacting faces. The previouslyreported effect of age of face on these judgments was also quali-fied by an interaction with motion condition, F(2,188) = 4.14,p <, .05. Simple effects analyses performed within each motioncondition revealed that age of face influenced the perceived ageof both reciting faces, F(2,188) = 154.87, p < .001, and interact-ing faces, F(2t 188) = 121.64, p < .001. However, middle-agedand older adult faces were thought to be older when reciting thealphabet than when interacting, Bonferroni rs(95) = 4.48 and3.22, respectively, p& < .05 (see Figure 5).

Analyses revealed that the previously reported impact of ageon the perceived femininity of dynamic faces also interactedwith motion condition, F(2,188) = 6.35, /?<.01. Simple effectsanalyses within each condition revealed that age influenced therated femininity of both reciting and interacting faces, Fs{2,188) = 26.26 and 30.89, respectively, p& < .001 (see Figure 6).For both reciting and interacting faces, children were judged tobe more feminine than were middle-aged adults, Bonferronirs(95) = 5.74 and 2.64, respectively, ps ^ .05. Although middle-aged and older adult reciting faces did not differ in femininityratings, ;(95) = 0.62, ns, middle-aged adult faces were judged tobe more feminine than older adult faces when interacting,t{9$) = 4.89, /><;.05.

Covariance analyses. Age of stimulus face had an impact onthe perceived age and femininity of reciting and interactingfaces. To ensure that these differences did not account for theimpact of age of face on perceived power, covariance analyseswere performed on power judgments within each motion con-dition. These controlled for both perceived age and femininity.These analyses again revealed a significant effect of chronologi-cal age of face on judgments of power when these variableswere controlled for both reciting faces, F(2,186)= 3.32, p<, .04,and interacting faces, F(2,186) = 24.24, p < .001. The magni-tude of the F ratios in these analysesdid drop when perceptionsof age and femininity were controlled. This indicates that, notsurprisingly, perceived age and femininity were responsible forsome of the variance in the perceived power of the faces. How-ever, the fact that these effects remain significant in the covari-ance analysis supports the hypothesis that information aboutdifferences in power related to chronological age is directlyavailable from age-related patterns of facial motion and neednot be mediated by these variables.

Discussion

What can a moving face tell us? These data reveal that pat-terns of facial motion provide knowledge about age-related per-son qualities. Specifically, moving point-light displays of adultfaces were perceived to be more powerful than were similar

displays of children's faces. Previous research has establishedthat the variations in craniofacial configuration resulting fromslow changes associated with growth also convey such knowl-edge (Berry & McArthur, 1986). However, the results indicatethat any information regarding such configural differences re-tained in the displays was not responsible for the observed ef-fects.

Dynamic facial qualities also exerted an impact on relativeage judgments. This raises the possibility that perceived agemediates the effect of facial age on judgments of power. Per-haps subjects extracted age information from the faces and thenbased judgments of power on their knowledge about differ-ences between children and adults. However, this explanation isrendered unlikely by the fact that stimulus persons at all agelevels were perceived to be adults. Moreover, when age judg-ments were statistically controlled, chronological age contin-ued to influence perceptions of the stimulus persons' power.

The data further revealed that dynamic facial informationinfluences gender-related perceptions. In particular, moving fe-male faces were judged to be more feminine than were malefaces. This is consistent with the finding that perceivers canaccurately identify the gender of dynamic point-light faces at arate above chance (Berry, 1990). Consistent with previous re-search (Berry, 1990; McArthur & Berry, 1986), younger faceswere also perceived to be more feminine than were older faces.However, analyses revealed that judgments of femininity couldnot account for the impact of facial age on perceived power.

The primary goal of these experiments was to demonstratethe complexity of the person information available in rapidfacial events. A second question involves the informational ba-sis of perceptions of power: How do moving faces convey thisknowledge? Some insight into this question is provided by acomparison of perceptions of reciting and interacting faces.Specifically, chronological age exerted the predicted impact onthe perceived power of faces reciting the alphabet and interact-ing. The reciting faces did not exhibit the socially elicited ex-pression changes available in interacting faces, yet they werecharacterized by highly similar movements. In fact, many sub-jects spontaneously noted that these faces were reciting the al-phabet. That such stereotypic movements were sufficient forthe communication of age-related person qualities indicatesthat a general invariant that influences all facial dynamics un-derlies these perceptions.

Cutting and his associates (Cutting, 1978; Cutting & Proffitt,1981) have proposed that center-of-moment is a general invari-ant that plays an important role in the extraction of informationfrom a range of events, including the detection of aging in theslow changes associated with facial growth, and the detection ofgender from gait. Perhaps age-related changes in facial struc-ture create age-related differences in the center-of-moment ofall facial motion. An analysis of the impact of age-dependentchanges in facial structure on dynamic facial qualities would beneeded to assess the validity of this proposition and to revealother possible bases for perceptions. Finally, it should be notedthat although socially elicited facial behaviors were not neces-sary for the detection of differences in power associated withchronological age, they did enhance perceivers* sensitivity tothis information. This is evidenced by the significant interac-tion of motion condition and chronological age of face on per-

MOVING FACES 1013

ceptions of power. Some researchers have found evidence thataspects of interpersonal facial behaviors do covary with age. Forexample, the incidence of partial expressions and blends in-creases with age (Malatesta & Izard, 1984). Such differencesmay account for the effects of socially elicited facial behaviorson the detection of power.

This research indicates that facial events constrained bygrowth reveal a great deal more than a person's age. In particu-lar, knowledge about the needs arid abilities of persons of dif-ferent ages is specified by these facial events. These results com-plement previous research that has demonstrated parallel ef-fects for age-related changes in facial configuration (Berry &McArthur, 1986). However, many important person character-istics are not constrained by such clearly anatomically definedvariables such as age or sex. Can this approach also yield insightinto how people detect those qualities? Runeson (1985) has pro-posed that transient states such as intention, attitude, motiva-tion, deception, and expectation share a relation with a person'sactions. Moreover, Runeson has provided a theoretical frame-work that describes how style of movement may define theproperties by which a person or object is constrained (cf. Rune-son & Frykholm, 1983). This approach calls into question thepopular view that most person qualities are hidden. A varietyof demonstrations, including that reported here, provide sup-port for Runeson^ position (cf. Berry, 1988, in press; Good,1987; Runeson & Frykholm, 1983,1986).

Fifty years ago, psychologists emphasized the role of percep-tion in the acquisition of social information (e.g., Heider, 1944,1959). Researchers have since opted to focus on the nature ofcognitive strategies and structures believed to provide meaningto incoming person data. The structure and meaning poten-tially available in stimulus information has often been over-looked. In fact, the current emphasis on cognition as a determi-nant of social knowledge has been justified, in part, by theassumption that most person qualities have no perceptible ex-ternal manifestations and are therefore apprehendable onlythrough inference. The data reported here add to an emergingbody of research on social event perception that challenges thisassumption. Person properties do structure visual information.Moreover, perceivers do extract meaning from that structure.Given this, a consideration of the perceptual support for personknowledge is vital to the development of a comprehensive un-derstanding of social knowledge acquisition.

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Received April 20,1988Revision received December 28,1989

Accepted January 2,1990 •