The Origin of Representational Drawing: A Comparison of ......(1978) reported that chimpanzee Moja, who learned American Sign Language (ASL), signed on her drawings “bird” when

The Origin of Representational Drawing: A Comparison of HumanChildren and Chimpanzees

Aya SaitoChubu Gakuin University

Misato HayashiKyoto University

Hideko TakeshitaThe University of Shiga Prefecture

Tetsuro MatsuzawaKyoto University

To examine the evolutional origin of representational drawing, two experiments directly compared the draw-ing behavior of human children and chimpanzees. The first experiment observed free drawing after modelpresentation, using imitation task. From longitudinal observation of humans (N = 32, 11–31 months), thedevelopmental process of drawing until the emergence of shape imitation was clarified. Adult chimpanzeesshowed the ability to trace a model, which was difficult for humans who had just started imitation. The sec-ond experiment, free drawing on incomplete facial stimuli, revealed the remarkable difference between twospecies. Humans (N = 57, 6–38 months) tend to complete the missing parts even with immature motor con-trol, whereas chimpanzees never completed the missing parts and instead marked the existing parts or tracedthe outlines. Cognitive characteristics may affect the emergence of representational drawings.

The oldest representational drawings in existence arethe upper Paleolithic cave drawings of Homo sapiens,who drew animals with a variety of materials andrefined techniques (Beltr�an, 2000; Chauvet, Des-champs, & Hillaire, 1996). A recent study usinguranium-thorium dating methods estimated thatsome of these drawings are more than 40,000 yearsold (Pike et al., 2012). Since that time, humans havecreated art by drawing or painting in every period inevery culture. Archeological findings, such asengraved pieces of ochre and shell beads, indicate thatour use of symbols emerged at least 100,000 years ago(Henshilwood, d’Errico, & Watts, 2009; Henshilwoodet al., 2011). Thus, it is reasonable to suggest thathumans had the cognitive capacity for producingrepresentational drawing when Homo sapiens emergedin Africa about 200,000 years ago. At the very least,it is likely that they had this capacity when theyspread out of Africa approximately 100,000 years ago.However, the underlying cognitive mechanisms fordrawing behavior are yet unknown.

Drawing Behavior in Chimpanzees

The present study aimed to assess the cognitivecapacity that led humans to begin drawing by

examining the drawing behavior of chimpanzees(Pan troglodytes), humans’ closest living relatives.Chimpanzees and humans share about 98.8% of thegenome (Chimpanzee Sequencing and AnalysisConsortium, 2005) and share a common ancestorthat existed until about 6 Ma. Chimpanzees showmarked similarities with humans in some aspect oftool using and social behavior. By comparingbehavior between the two species, we can inferolder cognitive traits shared with our commonancestor, and differences, the divergent newertraits, achieved separately by humans and chimpan-zees following evolutionary separation. Althoughthere are no reports of drawing behavior in wildchimpanzees, it is common for captive chimpanzeesto learn to draw or paint by manipulating a pen ora brush on paper. In the early attempts at studyingchimpanzee drawing, Kellogg and Kellogg (1933)and Ladygina-Kohts (1935/2002) individually caredfor chimpanzees along with their human childrenand compared the two species’ development ofmany behaviors, including drawing. Kellogg andKellogg reported that a chimpanzee scribbled afterobserving a model drawing, but she did not imitatethe human’s drawing. In contrast, human children

Correspondence concerning this article should be addressed toAya Saito, Faculty of Child Studies, Chubu Gakuin University,30-1 Nakaoida-cho, Kakamigahara, Gifu, 504-0837, Japan. Elec-tronic mail may be sent to [email protected].

© 2014 The AuthorsChild Development © 2014 Society for Research in Child Development, Inc.All rights reserved. 0009-3920/2014/xxxx-xxxxDOI: 10.1111/cdev.12319

Child Development, xxxx 2014, Volume 00, Number 0, Pages 1–15

preferred imitation. Ladygina-Kohts described stagesof scribbling in a chimpanzee, but not representa-tional drawings.

The first systematic study on chimpanzee repre-sentational drawing was conducted by Schiller(1951), who presented geometric figures to a chim-panzee, Alpha. Alpha changed her scribbling pat-tern depending on the stimuli. For example, shemarked on the relatively large figures drawn in thecenter of the sheet and scribbled in blank spacewhen presented with relatively small figures drawnin the periphery. She scribbled on the fracturedpiece of a Pacman-like figure or arranged circles.Schiller discussed those responses as balancing thecomposition, ascertaining that Alpha was capableof intuiting a human-like sense of order. Schiller’sstudies were followed by Morris (1962), Smith(1973), and later, Boysen, Berntson, and Prentice(1987). Like Schiller, these researchers reported thattheir chimpanzees marked on the figures or scrib-bled on blank space; however, they did not observethe balancing behavior observed by Schiller, andthus it appears problematic to claim that chimpan-zees possess a sense of order akin to what is likelythe origin of human aesthetic sense (Lenain, 1995,1997).

In most cases, drawing occurs spontaneously,that is, without food rewards or special training,and apes will draw or paint as self-gratifying play(Boysen et al., 1987; Lenain, 1997; Matsuzawa, 1995;Morris, 1962; Schiller, 1951; Smith, 1973; Tanaka,Tomonaga, & Matsuzawa, 2003). For this reason,drawing opportunities are sometimes proposed asenvironmental enrichment for great apes in captiv-ity. Despite decades of such experiences, however,chimpanzees’ drawings have consistently beenregarded as scribbles, without clear evidence forrepresentational figures. Gardner and Gardner(1978) reported that chimpanzee Moja, who learnedAmerican Sign Language (ASL), signed on herdrawings “bird” when they asked what it was. Thiskind of labeling was also observed in other ASL-trained chimpanzees or gorillas (Patterson, 1986).Nevertheless, to human eyes their works appearedto be no more than scribbles and it is difficult torecognize what, if anything, was represented on thepage.

Why is it that chimpanzees do not draw repre-sentational figures? Certain mechanisms mustunderlie the human capacity for representationaldrawing. For example, we must have motor skillsto control the lines, some cognitive function totranslate perception into action, as well as the moti-vation to pick up a writing utensil and draw.

Premack (1975) verified a likely cognitive factor. Ina composition task with fractured facial photo stim-uli that reduced motor demands, only a 12-year-oldchimpanzee named Sarah succeeded in completingan accurate configuration of the face; 3 other partic-ipants did not succeed.

The ability to manipulate tools by relating oneobject to another develops in chimpanzees just as itdoes in human children (Hayashi & Matsuzawa,2003; Takeshita, 2001). Generally, as chimpanzeesgain experience drawing, they become better atcontrolling their pens and are able to produce avariety of smooth lines (Gardner & Gardner, 1978;Kellogg & Kellogg, 1933; Ladygina-Kohts, 1935/2002; Morris, 1962; Tanaka et al., 2003). However,most previous reports concern only infant or juve-nile chimpanzees as participants, as it is difficult tocontrol adult chimpanzees safely in face-to-facesituations in order to conduct standardized experi-ments. In this study, we conducted experimentswith two juveniles and four adult chimpanzees, allof whom had considerable experience participatingin face-to-face experiments due to their long-termrelationships with a human tester (Matsuzawa,2009).

In order to test our hypotheses with chimpanzeeparticipants who had considerable drawing experi-ence, we devised two experiments: free drawingafter presentation of a model (Experiment 1) andfree drawing on illustrations of a chimpanzee face(Experiment 2). In general, after human childrenbegin scribbling at around 1 year of age, their scrib-bling develops from accidental markings to con-trolled lines, and it gains variation as their motorskills develop. They finally begin to draw represen-tational figures when they are around 3 years ofage (Cox, 1992; Saito, Hayashi, Ueno, & Takeshita,2011). Although many studies have been conductedon child drawing, the majority of systematic studiesfocused on representational drawing of childrenolder than 3 or 4 years of age (e.g., Arnheim, 1954;Freeman, 1972; Golomb, 1973; Goodnow, 1977). Thestudies conducted on scribbling stages have beenlimited to longitudinal observation studies of oneor a few children (Eng, 1954; Luquet, 1927) or across-sectional study by collecting the drawn fig-ures of a large number of children (Kellog, 1969).We carried out the same experiments in chimpan-zees and human children to establish a comparativescale of development. Based on the results of thetwo experiments, we discussed potential explana-tions for the scale of development and to thusexplore the cognitive basis of representationaldrawing.

2 Saito, Hayashi, Takeshita, and Matsuzawa

Experiment 1

In order to evaluate the motor skills necessary forfigure drawing, a prerequisite for the emergence ofrepresentational drawing, we used imitation-of-model drawing. Although the imitation task is acommonly used developmental assessment tool,there is a lack of research on the developmentalprocesses underlying the change from simple scrib-bling to successful imitation. Previous studies ofdrawing on premarked stimuli indicated that manychimpanzees change their scribbling position tomark the stimuli or blank space (Boysen et al.,1987; Morris, 1962; Schiller, 1951; Smith, 1973).Matsuzawa (1990, 2000) reported that an adultchimpanzee named Chloe spontaneously traced adrawn circle. In this study, we modeled the draw-ing of simple figures and observed the drawingbehavior of participants on the same sheets. Thematerials and procedures were kept the same forchimpanzees and humans in order to directly com-pare their motor-control ability. The longitudinalobservation of human children permitted analysisof not only when children succeeded in imitating,but also how their scribbles developed until suc-cessful imitation emerged.

Method

Participants

Human participants were 32 Japanese children(13 boys and 19 girls) who ranged in age from11 months to 31 months at the time of the first test-ing session. They were members of the UmikazeInfant Laboratory at the University of Shiga Prefec-ture, Japan, recruited from the surrounding area.We tested each participant once every 2–3 monthsfrom September 2005 to April 2009, although theentry date and the duration varied for each child.All experiments complied with the laws of Japanand were approved by the Human Ethics Commit-tees of the Primate Research Institute of Kyoto Uni-versity and the University of Shiga Prefecture.Informed consent was obtained from the parents ofall participants.

Chimpanzee participants were 4 adult and 2juvenile chimpanzees (Table 1), living in a group of14 chimpanzees at the Primate Research Institute ofKyoto University, Aichi Prefecture, Japan. All hadpreviously participated in cognitive experimentsusing a touch-screen computer. The chimpanzeeswere familiar with the experimental setting andwith face-to-face situations with human testers since

childhood (Hayashi & Matsuzawa, 2003; Hayashiet al., 2009; Matsuzawa, 2009), and all had somedegree of drawing experience before this study(Hayashi & Matsuzawa, 2003; Tanaka et al., 2003).Two mother–infant pairs (Ai and Ayumu, Pan andPal) had also participated in a free-drawing taskusing a touch-screen computer (Tanaka et al., 2003).Prior to the study, all chimpanzee participants prac-ticed free drawing on blank paper to allow observa-tion of their freestyle drawing and to familiarizethem with the materials and the experiment face-to-face situation.

Procedure

We used an imitation-of-model drawing, whichwas standardized as a developmental scale forhuman children (Kyoto Scale of PsychologicalDevelopment; Ikuzawa, Matsushita, & Nakase,1985) with a simplified procedure. The experimentswere carried out individually and face-to-face forboth human and chimpanzee participants. Childrenwere also tested in other object-manipulation taskson the same day (Hayashi, 2007; Hayashi & Takesh-ita, 2009; Hayashi et al., 2009). Our experimentswith chimpanzees were conducted directly after thecomputer experiments at the same experimentalbooth. Human children sat beside their parent or ontheir lap while a tester sat across from them at alow table in a quiet room at the laboratory. Chim-panzee participants sat on a wooden board on thefloor in front of a human tester in the booth. Theprocedure was nearly identical for human andchimpanzee participants and used the same materi-als, namely, B4-sized paper (257 mm 9 364 mm)and water paint markers. A session started with afree drawing trial, which allowed the participant todraw freely on a blank paper. The tester said, “Let’sdraw on this,” and observed the participant’s draw-ing behavior for at least 1 min. We used the firstfive figures from the Kyoto Scale of PsychologicalDevelopment (Ikuzawa et al., 1985) for a session: (1)

Table 1Chimpanzee Participants in Experiments 1 and 2

Name Age in years Sex

Akira 29 Adult MaleAi 28 Adult FemalePopo 23 Adult FemalePan 21 Adult FemaleAyumu 5 Juvenile MalePal 5 Juvenile Female

The Origin of Representational Drawing 3

horizontal lines, (2) vertical lines, (3) a circle, (4) across, and (5) a square. In each trial, the tester drewa model figure with a pale orange marker in front ofthe participants while saying, “Can you draw likethis?” Then, the participant drew on the same paperwith a marker of a different color so as to identifythe lines in later analysis. If the participant did notsucceed in imitating within 30 s, the tester demon-strated the model drawing again by tracing themodel figure and then observed for another 30 s ormore. The drawing behavior of the participants wasrecorded using two digital video cameras set at dif-ferent angles.

In a given experimental day, human childrenparticipated in one session consisting of a freedrawing trial and two to five model figure trials,depending on their concentration and their previ-ous success in imitation. For very young childrenwho could not imitate the first figures and had dif-ficulty in keeping concentration for many trials, werandomly chose two figures, one from line figures(1) or (2), and one from geometric figures (3) or (5)in order to counterbalance comparisons of theirscribbling patterns with chimpanzees.

Chimpanzees participated in three sessions atintervals of 1½ months. We used fruit to maintaintheir motivation but not to reward any specificdrawing behavior.

Data Analysis

We analyzed data from 679 trials from 286sessions with human infants, and 87 trials from 19sessions with chimpanzees. The mean number ofsessions for a child was 9.0 (SD = 4.7) during 31.7(SD = 13.6) months of observation period with 3.2-(SD = 0.8) month intervals. The age of the first suc-cessful imitation was defined as the age at which achild first imitated a figure that he or she had notpreviously imitated in longitudinal observations.This analysis did not include cases in which chil-dren succeeded on the very first trial. The successof an imitation was evaluated by using the criteriaof the Kyoto Scale of Psychological Development(Ikuzawa et al., 1985; see Appendix S1 in the onlineSupporting Information).

Next, we used the failure trials before the firstsuccessful imitation of the figure for humans andcompared the drawing patterns with those of thechimpanzees. Typical behavior patterns were identi-fied by focusing on changes in position and scrib-bling touches compared to the first free drawingtrial: (a) scribbled randomly: scribbled without clearchange in position and touch; (b) marked the

figure: moved scribbles to mark the model figure;(c) similar lines: change in scribbling touchesdepending on the model figure (e.g., horizontal upand down strokes increased after the presentationof horizontal lines or spiral scribbles increased aftera circle presentation); (d) imperfect imitation:attempted to draw the model figure but the criteriafor success were not met; and (e) traced the modellines: traced a part of the model lines. From thevideo recordings, a main rater (A. S.) checkedwhether each categorized behavior was observed ina trial. To assess interrater reliability, an additionalrater watched video recordings of 214 of 355 trialsin humans and 87 of 87 trials in chimpanzees andchecked the participants’ behavior. The main raterand the second rater agreed on each categorizedbehavior on 97.8% of the trials. From the longitudi-nal data of individual children, we considered thefirst occurrence of each of the four categorizedbehaviors and the first success of imitation andcompared the occurrence ages by a one-wayrepeated measures of analysis of variance (ANOVA).The frequencies of the categorized behaviors werecalculated in each of five age ranges in humans(11 months to 1 year 5 months: 65 trials analyzed;1 year 6 months to 1 year 11 months: 96 trials;2 years to 2 years 5 months: 72 trials; 2 years6 months to 2 years 11 months: 57 trials; 3 years:65 trials) and two groups of chimpanzees (juveniles:27 trials; adults: 60 trials).

Results

From longitudinal human observations, the aver-age age of the first successful imitation is shown inTable 2. On average, human children succeeded inimitating horizontal lines at 2 years 4 months, verti-cal lines at 2 years 6 months, a circle at 2 years11 months, a cross at 3 years 5 months, and asquare at 4 years. A one-way repeated measuresANOVA showed main effects of figure, F(4, 80) =36.2, p < .001, g2p ¼ :64. Post hoc Tukey–Kramer’shonestly significant difference (HSD) comparisonsbetween the factors revealed a significant differencebetween all figures except for horizontal and verti-cal lines. Table 2 also shows the average age of thefirst occurrence of each categorized behavior beforetheir first success in imitation. They marked themodel figure at 1 year 5 months, drew similar linesat 1 year 10 months, drew imperfect imitations at2 years 5 months, and traced the model lines at2 years 8 months, on average. A one-way repeatedmeasures ANOVA revealed a main effect forcategorized behaviors, F(3, 71) = 22.8, p < .001,


g2p ¼ :49. Post hoc Tukey–Kramer’s HSD compari-sons between the categorized behaviors revealedsignificant differences between (b) mark the figureversus (c) similar lines (p < .05), (c) similar linesversus (d) imperfect imitation (p < .05), and (c)similar lines versus (e) trace the model lines(p < .05). No significant difference was foundbetween (d) imperfect imitation versus (e) tracethe model lines. Examples of the products by cate-gorized behaviors and the frequency in each ageperiod for humans and chimpanzees are shown inFigure 1. Juvenile chimpanzees scribbled randomly(40.7% of trials) or marked the figure (59.3%),whereas adult chimpanzees also marked the figure(36.7%) and three of four adult chimpanzees drewsimilar lines (15.0%) or traced lines (11.7%). How-ever, none of the chimpanzees attempted to imi-tate the figure.

Discussion

Through a longitudinal analysis, we clarified thehuman developmental trajectory for scribbling pat-terns before the emergence of imitative figure draw-ing. First, children moved their scribbles to markthe model. Second, they tried to change their scrib-bling touches similar to the model’s movement,and third, they intended to imitate figures, whichultimately led to success upon maturation ofmotor skills. Although chimpanzees did not draw adistinct figure by imitating the model presentation,they changed the position of their scribbles to markthe model or marked a blank space and, further,changed their scribbling behavior after model pre-

sentation. These findings resembled the responsesof chimpanzees in former studies (Morris, 1962;Schiller, 1951; Smith, 1973). Model presentation,however, seemed to enhance reactivity, a findingthat was different from previous studies presentingpremarked shapes. Moreover, some adults showedthe ability to control their lines to trace the model.Tracing behavior is not extraordinary for chimpan-zees, as Matsuzawa (1990) has previously reportedthat a chimpanzee named Chloe spontaneouslytraced a drawn circle. It is also possible to teachchimpanzees to trace a line with a finger on atouch-screen monitor through the use of reinforce-ment (Iversen & Matsuzawa, 1996). Our resultsindicated that tracing was even difficult for humanchildren who had just started imitating the easiestfigures. Changing their lines and tracing was onlyobserved in adult chimpanzees but not in juvenilechimpanzees, which demonstrated that the adultshad matured motor skills requisite for controllingtheir strokes (Figure 2).

These results indicated that chimpanzees developdrawing skills and at least three adults had the abil-ity to finely control their manual movements whendrawing lines to trace model lines. Thus, theobserved lack of representational drawing in chim-panzees does not appear to be due to inadequatemotor ability.

In order to copy the figures, not only are motorskills required, but also the cognitive capacity tocompare the shape of one’s drawing to the modelfigure. However, in this experiment, we argue onlyfor motor ability as we assumed that this task wasnot imitative model drawing but a task of free

Table 2The Average Ages at the First Occurence of Each Typical Behavior and the First Successful Imitation in Individual Humans

Note. N indicates the number of participants who showed each typical behavior during the longitudinal observation.*p < 0.05 (Tukey–Kramer post hoc multiple comparison test).


Figure 1. Examples of the products of the main categorized behaviors and their frequency in each age period for humans and chimpan-zees in Experiment 1.


drawing after model presentation. Despite receiv-ing the same ambiguous verbal instructions, it ispossible that the two species differed in the degreeof understanding for the task objective to imitatethe figure. Therefore, we could not conclude thatchimpanzees are unable to imitate the shape of amodel. In fact, some of the adult chimpanzeesspontaneously changed their scribbling pattern toshape similar lines seemingly in an effort to imi-tate the model’s movement. For instance, chimpan-zee Pan, who ordinarily drew short vertical lines,suddenly drew a long horizontal line during a trialof horizontal lines, and she successfully tracedlong vertical lines. Iversen and Matsuzawa (1997)taught chimpanzees to draw a straight line parallelto a presented line using their finger on a monitor.Success occurred only when a starting point wasprovided as a guide on the monitor, and itrequired a great deal of trial and error. It is note-worthy that chimpanzees were not proficient atimitating a human’s behavior, particularly whenthe actions were not directed toward anotherobject or their own body (Myowa-Yamakoshi &Matsuzawa, 1999). It is likely that imitating amodel figure constitutes an advanced level of imi-tation that requires not only simply directing apen toward the paper but also adequately con-trolled manual movements on the paper. In thiscase, chimpanzees must perceive the relationbetween their own manual movements and themanifest results on the drawing.

Experiment 2

Results from Experiment 1 showed that adult chim-panzees had sufficient motor skills to control theirlines as required to trace a model line. Thus, theabsence of representational drawing in chimpanzees

was not caused by a lack of motor control. Experi-ment 2 was designed to investigate the underlyingcognitive mechanism, another prerequisite for theemergence of representational drawing. Humanchildren in the early stages of representationaldrawing will often draw faces of humans oranimals, and it is easy for others to objectively per-ceive what is represented. To assess the representa-tional ability of children in scribbling stage, somestudies have used a design in which an incompletefigure is presented, and the child is asked to com-plete it. It has been demonstrated that children whocannot yet draw representational figures by them-selves fill in some missing parts inside the contoursof illustrated figures (Freeman, 1977; Yamagata,2001). A study in which children were allowed toscribble on picture books showed that even 1- or 2-year-olds who were still in the scribbling stageoften marked on human or animal figures, particu-larly on their faces (Yamagata, 1991). It was alsoreported that adult chimpanzee Ai marked humanand animal figures that appeared in picture books(Matsuzawa, 1995). We used incomplete figures todirectly compare representation ability of twospecies.

In order to determine whether the chimpanzeeswould fill in the missing parts, we prepared anillustrated figure of a chimpanzee’s face and deletedfacial parts to make an incomplete-face stimulus.As the marking behavior on picture books indicated(Matsuzawa, 1995), chimpanzees did seem to recog-nize illustrated figures. Chimpanzee Ai even recog-nized familiar chimpanzees and humans portrayedin line drawings and matched them with the letterof the alphabet that corresponded to the individ-ual’s name (Itakura, 1994). In the present experi-ment, chimpanzees’ spontaneous drawing behavioron the incomplete-face stimulus was observed andsubsequently compared with that of human chil-

Figure 2. A tester drew a circle as a model presentation (left), and chimpanzee Pan traced the circle (right).


dren of different ages. We also analyzed children’scomments on stimuli and the drawings thatoccurred with each categorized behavior in order toinvestigate the relation between their recognitionand representation.

Method

Participants

Fifty-seven human participants (23 boys and 34girls) ranging in age from 1 year 6 months to3 years 2 months participated in Experiment 2. Thechildren were members of “Umikaze” Infant Labo-ratory of the University of Shiga Prefecture and allof them already participated in Experiment 1. Theexperiments were conducted with other object-manipulation tasks on the same day (Hayashi,2007; Hayashi & Takeshita, 2009). The children tookthis drawing test 2 or 3 times at intervals of morethan 3 months. The chimpanzee participants werethe same as in Experiment 1 (Table 1). All experi-ments complied with the laws of Japan and wereapproved by the Human Ethics Committees of thePrimate Research Institute of Kyoto University andthe University of Shiga Prefecture. Informed con-sent was obtained from the parents of human par-ticipants, and the data were treated carefully toprotect their privacy.

Apparatus

B4-sized (257 mm 9 364 mm) paper and paintmarkers were used for drawing. We prepared anillustration of a chimpanzee face outline from aphotograph using Adobe Photoshop. The illustra-tions were printed in 2-mm-wide gray lines, whichwere of similar width to the marker lines and dis-tinguishable from the black lines of participants inlater analysis. Facial features were deleted to con-struct the following stimuli: (1) normal face, (2)right eye missing, (3) left eye missing, (4) both eyesmissing, and (5) outline only. A session consistedof five trials, with the stimuli presented in thatorder.

Procedure

The experimental setting was identical to Experi-ment 1, and the procedure was again carried out inindividual face-to-face interactions for both humanand chimpanzee participants.

A tester passed a black pen to a participant andsaid, “Let’s draw on this, just as freely as you like.”

Participants were not instructed on what to draw inregard to the absence of facial parts. We observedas the participants drew on the paper for 30 s ormore from their first mark. We did not designatethe “completion” as a correct reaction in this taskand the tester did not provide feedback by vocalreward. We used fruit to maintain the motivationof chimpanzees but did not reward any specificdrawing behavior. The drawing behavior of theparticipants was recorded using two digital videocameras set at the different view angles.

Data Analysis

We analyzed 285 trials from 57 sessions withhumans and 60 trials from 12 sessions with chimpan-zees. We identified five typical patterns of behavioron imperfect Stimuli 2 through 5: (a) marked thewhole face: scribbling mainly inside the whole facebut not limited to specific parts; (b) scribbled onblank space: scribbling outside the face area; (c)marked the present parts: scribbling to mark thedrawn facial parts; (d) completed the missing parts:draw eyes, nose, or mouth to complete the face; and(e) traced the outlines: tracing on the contours of theface. A main rater (A. S.) determined whether eachcategorized behavior was observed in a trial fromthe video recordings. To assess interrater reliability,an additional rater watched video recordings in190 of 285 trials in humans and 30 of 60 trials inchimpanzees and checked the participants’ behavior.The main rater and the second rater agreed withthe rating of each categorized behavior in 97.1%of the trials, indicating strong interrater reliabil-ity. The frequencies for categorized behaviors werecalculated in each of five human age groups (1 year6 months to 1 year 9 months, 1 year 10 months to2 years 1 month, 2 years 2 months to 2 years5 months, 2 years 6 months to 2 years 9 months,and 2 years 10 months to 3 years 2 months) and twogroups (juveniles and adults) in chimpanzees(Table 3). We compared frequencies using a 1-dfCochran–Armitage trend test. Additionally, we ana-lyzed the spontaneous speech of human children.We checked the presence or absence of comments inregard to missing parts of stimuli before they startdrawing such as “no eye” or “eyes missing” andcomments about their drawn parts such as “eye” or“mouth” or about their drawn face such as “face” or“monkey” during or after drawing. To assess therelation between the verbalization and the drawingbehaviors, we recategorized each trial into one of thefour independent behavioral categories based on thebest performance in each trial: (a) completion; (b)


imperfect completion, for example, drawing toomany eyes or indistinct eyes; (c) marking parts; and(d) marking face. Then, we compared the mean ageand the frequency of spontaneous verbalization ofchildren among the four behavioral categories of tri-als. Statistical significance was evaluated by anANOVA for age followed by Tukey–Kramer HSDanalysis and by Cochran–Mantel–Haenszel test fol-lowed by residual analysis for the frequency of eachtype of verbalization.

Results and Discussion

The frequency of each categorized behavior onmissing parts stimuli is presented by age group andspecies in Figure 3. The most frequently observedbehavior in younger human groups was “mark thewhole face.” The frequency of “mark the presentparts” increased with age in humans (v2 = 12.9,p < .01 by 1-df Cochran–Armitage trend test). “Com-plete the missing parts” increased with age(v2 = 48.8, p < .001) and was the most frequentlyobserved behavior in the two groups of humansaged 2 years 6 months or older. On the contrary,none of the chimpanzees completed the missingparts; instead, they marked the whole face (90.0% ofthe trials in juveniles, and 27.5% of the trials inadults), scribbled on blank space (0% in juveniles,and 42.5% in adults), or marked the existing part(25.0% in juveniles, and 30.0% in adults). Moreover,adult chimpanzees traced the outlines of the face in22.5% of trials, a behavior that increased with theage in humans, particularly after 2 years 6 months(v2 = 19.9, p < .001). Chimpanzees’ motor skills weremore refined in their marking of existing parts andmarking the existing outline but not, however, incompleting the missing parts. Conversely, humanchildren demonstrated an ability to fill in missing

parts of faces. In most human cases, tracing occurrednot independently (except for three cases by a child),but simultaneously with other categorized behav-iors, namely, completion (30.6% of trials), markingparts (58.3%), and marking whole face (55.6%).

Therefore, we identified four main phases ofdevelopment in human children. First, markingwithin the facial outline; second, marking on exist-ing parts; third, filling in the missing parts butimperfect; and fourth, completing the missing parts.Stated otherwise, the marking of existing partsgradually converges on distinct facial parts fromthe whole face before the emergence of missing partcompletion. We selected trials that contained thesetypes of behavior and recategorized them into thefour phases independently based on the best perfor-mance in each trial. That is, if a trial was catego-rized in one phase, the trial could not be placed inanother phase. The mean age and the frequency ofchildren’s spontaneous speech in four behavioralcategories of trials with the data for “tracingoutlines” as a reference are shown in Table 4. Aone-way repeated measures ANOVA revealed asignificant difference in ages among four catego-rized groups, F(3, 166) = 21.2, p < .0001, g2p ¼ :08.Post hoc Tukey–Kramer’s HSD comparisonsshowed the significant age difference between“completion” versus “marking parts” or “markingface,” “failure completion” versus “marking face.”A Cochran–Mantel–Haenszel test revealed that thefrequency of verbalization before drawing differedby categorized group of trials, v2(3) = 23.4,p < .0001, Cramer’s V = 0.35, and verbalizationduring or after drawing by categorized group,v2(6) = 6.4, p = .039, Cramer’s V = 0.17. Residualanalysis showed that reference to missing parts wasmore frequent in “completion” and “failure comple-tion” groups and less frequent in “marking parts”

Table 3Age Groups in Humans and Chimpanzees, Experiment 2

Age groupsNumber ofsubjects

Number ofsessions

Numberof trials Mage (SD)

Humans1 year 6 month to 1 year 9 month 10 10 55 1 year 8 month (1 month)1 year 10 month to 2 year 1 month 8 8 45 2 year 0 month (1 month)2 year 2 month to 2 year 5 month 17 17 90 2 year 4 month (1 month)2 year 6 month to 2 year 9 month 10 10 50 2 year 8 month (1 month)2 year 10 month to 3 year 2 month 8 8 45 3 year 0 month (1 month)

ChimpanzeesJuveniles 2 4 20 6 year (0 year)Adults 4 8 40 27 year (3 year)


Figure 3. Examples of the products of main categorized behaviors and their percentage by different human and chimpanzee age groups(the number of trials with the behavior/total trials).


and “marking face” groups. More than half of thechildren mentioned missing parts before completingthe task, even if the end result was imperfect, indi-cating that they spontaneously tried to completethe missing parts, in spite of their lack of motorskill. Verbal behavior during or after drawing wasobserved more frequently in “completion” and lessin “marking face.” Further, 15.4% of the children(n = 4) who marked the existing parts mentioneddrawn parts, while none of them mentioned theface or object during or after drawing, suggestingthat they recognized the drawn parts and perhapsintended to draw but did not notice the parts miss-ing. On the other hand, in “marking face,” only1.6% of the children (n = 1) mentioned drawn parts,while 10.9% (n = 7) mentioned the drawn face later,indicating that they recognized the face but had notnoticed the drawn or missing parts.

Although chimpanzees were likely to recognizethe illustrated face, as former studies indicated, it isunclear whether they failed to recognize the incom-plete figure as a face, recognized it but did notnotice the absence of the parts, or noticed theabsence of the parts but had no motivation tocomplete them. Further investigation is neededto address this issue, especially with respect tochimpanzee’s symbolic capacity when processingthe incompletely drawn figures.

However, chimpanzees might direct their atten-tion toward the outline rather than the target facialfeatures, since the frequency of the behavior “tracethe outlines” by the adult chimpanzees was higher

than it was for humans under 2 years 9 months. Incontrast, the frequency of the behavior “mark thepresent parts” was lower for adult chimpanzeesthan for humans older than 2 years 6 months.

General Discussion

Cognitive Foundation for Representational Drawing

This study approached the emergent representa-tional drawing ability of young children and illus-trated their similarities and differences withchimpanzees by directly comparing the two speciesin two experiments. The longitudinal study ofExperiment 1 investigated and shed light on thedevelopmental trajectory of human drawing fromscribbling to successful copying of a shape. Chim-panzees not only marked the figures, which is acommon response to these stimuli, but also tracedthe lines in a similar manner to the humanchildren in the early stages of imitation ability,showing adequate motor-control skills. Adult chim-panzees exhibited a greater array of drawing pat-terns on stimuli than did juvenile chimpanzees,indicating more mature motor-control skills in theformer. Experiment 2 demonstrated a remarkabledifference between the two species. Humans drewmissing parts despite more limited motor control,whereas adult chimpanzees marked only existingfigures. These results indicated that the lack of rep-resentational drawing in chimpanzees was not dueto a motor deficit but derived from a cognitive

Table 4Percentages of Spontaneous Referral to Missing Parts Before Drawing and Comments on Drawn Parts or Drawn face During or After Drawing onStimuli 2 Through 5

Type of behavior N

Age

Spontaneous verbalization

Before drawingDuring or after drawing

M (SD) Range Missing parts (%) Drawn parts (%) Drawn face (%)

(a) Complete the missingparts

69 2 year 8 month(4 month)

2 year 0 month to3 year 2 month

55.1** 29.0** 10.1

(b) Fill in the missing partsbut imperfect

34 2 year 7 month(4 month)


55.9** 23.5 5.9

(c) Mark the existing parts 26 2 year 4 month(5 month)


11.5* 15.4 0.0

(d) Mark the whole face 64 2 year 2 month(4 month)


3.1** 1.6** 10.9

Trace the outlinesa 20 2 year 8 month(4 month)


50.0 30.0 10.0

Note. N indicates the number of trials categorized into the four types of behavior independently.aWe excluded this category of data from the statistical analysis as it contains overlapping data with other categories.*p < .05. **p < 0.01 (residual analysis).


process necessary for drawing missing parts tocomplete an image. Although Premack (1975)reported that a chimpanzee named Sarah correctlyconfigured facial parts, three other chimpanzeesfailed. The task used here, namely completing aface by filling in missing parts without assistance,appears more complex than simply organizingexisting parts.

Figures on a paper may trigger imagination inhumans that is not possible in chimpanzees. Per-haps this is the faculty that assists humans in draw-ing representational figures. In Experiment 2, somemothers whose children completed the missingparts explained that it was the first time their chil-dren had drawn a representational figure. In addi-tion, many children over 2.5 years old drew therepresentational figures inspired by the modelsobserved in Experiment 1 (Figure 4). They mayhave conceived an imaginary shape of objects froma composition of lines and completed it by addingthe missing parts. During longitudinal observationsof drawing, about 48% first-time representationalfigures (by 11 of 23 children) were observed inmodel drawing trials following the absence of anyclear representation in earlier free-drawing trialsduring the same session (Saito et al., 2011). Somestimuli, including even simple abstract figures, cantrigger imaginative representations in young chil-dren, especially those in the transition period fromscribbling to representational drawing.

Ancient cave art indicated that Paleolithichumans also imagined animals and drew missing

parts to complete their images although the situa-tions were obviously not the same with our experi-mental settings. For example, the famous bison ofAltamira were drawn on swells of the dome, andthe contours of the bodies were sometimes conflu-ent with natural cracks on the rock. There is also a“mask” with eyes filled in on the hanging parts ofrock that resembles a face silhouette. Humans havea strong tendency to imagine novel configurations,even in ambiguous images such as a spot on thewall or clouds in the sky (Gombrich, 1972; Guthrie,1993). This cognitive trait may be a defining featuredistinguishing Homo sapiens from other ancestorswho did not develop representational drawing.

Why Do We Have the Cognitive Trait of Imagination?

In our study, motorically capable chimpanzeesmarked strictly on the small parts or lines, that is, alocalized area. This tendency might be related tochimpanzees’ lack of global processing in compari-son to humans, who have strong global processingabilities (Fagot & Tomonaga, 1999). Humans alsoexhibit greater temporal integration accuracy thando chimpanzees in the task of dynamic shapeperception under a slit-viewing condition (Imura &Tomonaga, 2013). Global processing may be relatedto imaginative recreations of abstract figures, as itleads to Gestalt perception and object recognition.

Imagination can be described as perceiving apercept as “something” and categorizing lowerlevel visual information into the concept of “some-thing” by associating it with a symbol otherwiserepresented in the mind. This symbolic cognitivesystem is further evident in the case of human lan-guage, and is indeed the premise behind humanlanguage, and humans tend to imagine somethingeven in response to ambiguous figures (Humphrey,1998). Many studies have indicated that chimpan-zees have the ability to learn some symbols, such ascharacters and numerals, and even to understandsome sign language (e.g., Matsuzawa, 1985a,1985b). Therefore, we could not conclude that chim-panzees never have imaginative capability onlyfrom the result of the present study. Some chim-panzees especially who experienced symbol train-ing may have some primitive capability ofimagination based on the primitive symbolicalcapability, as one of the chimpanzees who engagedin language training correctly configured facialparts in the simple task of organizing existing partsin Premack’s (1975) study.

On the other hand, symbolic systems in humansare much prevalent and also reflected in representa-

2 y 5 m Girl “Railroad” 2 y 7 m Boy “Train”

2 y 8 m Girl “Anpanman” 3 y 1 m Boy “Bus, Starts!”

Figure 4. Human children sometimes drew spontaneous repre-sentations inspired by the models in Experiment 1. The indicatedage, gender, and verbal explanation by the child. They used theirimaginations with the presented lines and completed theirimages by adding some “missing” parts.


tional drawings of children as the former studiesindicated. For example, Arnheim (1954) disputesthe assumption that problems of form in youngchildren’s drawing can simply be decoded intoproblems of content, by discussing the meaning ofwell-known phenomenons such as “transparency”and “tadpole man.” As children’s representationaldrawings are very symbolic, as opposed to a copyof the real object (Luquet, 1927), they might directlyreflect the development of knowledge while thechildren are expanding their conceptions of objectsas a symbol. A phenomenon known as orientationindifferent representation arises in the early repre-sentational period, where children draw a figure inan inverted or horizontal orientation. This phenom-enon can be induced by presenting stimulus figuressuch as illustrations of ears of a cat in differentorientations. Some younger children draw facialparts in a rotated orientation on rotated stimuli andin an upright orientation on upright stimuli. Itseems that the younger children are indifferent tothe orientation of the face on the plane to draw.Since they may know the relative order of the facialparts in the whole face, they do not show difficultydrawing the rotated face in a given orientation. Onthe other hand, older children always intended todraw facial parts in an upright orientation: Theyreorient the sheet into the upright position beforethey start drawing. These age differences in reactionto inverted stimulus figures indicate a relationbetween the production and development of thefacial symbol (Saito et al., 2011).

In Experiment 2, human children marked onthe presented figures, similar to chimpanzees,before they started to complete the missing parts.However, when they noticed the absence of cer-tain features, they embraced the challenge to com-plete them, despite their lack of motor skills incomparison to chimpanzees. It is noteworthy thatthe tester only instructed participants to “drawfreely” and did not acknowledge “completion” asa correct reaction. In addition, some children drewindependent representational figures on blankspace. In contrast, chimpanzees never completedthe missing features whereas more than half ofthe humans aged over 2.5 years did so spontane-ously. As Freeman (1977), Matthews (1984), andYamagata (2001) pointed out, even young childrenin the scribbling stage have the intention of repre-sentation.

It must be noted that human participants likelypractice drawing outside of the experimental con-text far more often than chimpanzees. Such behav-ior might be encouraged by social motivation, as

early representational drawing evokes a great dealof vocal communication between children and theirparents and others given the joint attention drawnto their figures. Besides, humans, unlike chimpan-zees, are socialized starting in infancy to use paperfor drawings, to view pictures, and other two-dimensional imagery. Drawing enables the sharingof an inspired image in one’s mind, and it is likelythat this is a strong motivation for making repre-sentational drawing in human children.

Human infants are brought up to socialize inupright positions and are encouraged to engage inface-to-face communication with other people(Takeshita, Myowa-Yamakoshi, & Hirata, 2009). Wespeculate that this abundance of social interactionsince birth would enhance human children’s abilityto internalize others’ varied viewpoints, stronglymotivate them to share with others, and play animportant role in the development of imagination.This development of imagination should manifestin the completion of missing parts in images. It isbelieved that humans have evolved a great deal oftheir characteristic complex behavior through cul-tural learning (Tomasello, 1999). Chimpanzees alsohave primitive social-learning ability in the acquisi-tion of tool-using skill, such as “education by mas-ter-apprenticeship” (Matsuzawa et al., 2001) orbonding- and identification-based observationallearning (De Waal, 2001). However, enhanced cul-tural learning in humans may have played animportant role in more than 30,000 years of art his-tory among Homo sapiens and, further, seems to beone of the primary drivers of the emergence ofrepresentational drawing.

References

Arnheim, R. (1954). Art and visual perception: A psychologyof the creative eye. Berkeley: University of CaliforniaPress.

Beltr�an, A. (2000). The cave of Altamira (Japanese transla-tion, Y. Ohtaka & M. Ogawa, Trans.). Tokyo, Japan:Iwanami Shoten.

Boysen, S. T., Berntson, G. G., & Prentice, J. (1987). Sim-ian scribbles: A reappraisal of drawing in the chimpan-zee (Pan troglodytes). Journal of Comparative Psychology,101, 82–89. doi:10.1037/0735-7036.101.1.82

Chauvet, J. M., Deschamps, E. B., & Hillaire, C. (1996).Chauvet cave: The discovery of the world’s oldest paintings.London, UK: Thames and Hudson.

Chimpanzee Sequencing and Analysis Consortium.(2005). Initial sequence of the chimpanzee genome andcomparison with the human genome. Nature, 437, 69–87. doi:10.1038/nature04072


Cox, M. V. (1992). Children’s drawings. London, UK: Pen-guin Books.

de Waal, F. (2001). The ape and the sushi master: Culturalreflections of a primatologist. New York, NY: Basic Books.

Eng, H. (1954). The psychology of children’s drawings (2nded.). London, UK: Routledge and Kegan Paul.

Fagot, J., & Tomonaga, M. (1999). Global-local processingin humans (Homo sapiens) and chimpanzees (Pan troglo-dytes): Use of a visual search task with compound stim-uli. Journal of Comparative Psychology, 113, 3–12. doi:10.1037/0735-7036.113.1.3

Freeman, N. H. (1972). Process and product in children’sdrawing. Perception, 1, 123–140. doi:10.1068/p010123

Freeman, N. H. (1977). How young children try to plandrawings. In G. E. Butterworth (Ed.), The child’s represen-tation of the world (pp. 3–29). London, UK: Plenum Press.

Gardner, R. A., & Gardner, B. T. (1978). Comparativepsychology and language acquisition. In K. Salzinger &F. Denmark (Eds.), Psychology: The state of the art.Annals of the New York Academy of Sciences, 309, 37–76.doi:10.1111/j.1749-6632.1978.tb29441.x

Golomb, C. (1973). Children’s representation of thehuman figure: The effects of models, media, andinstruction. Genetic Psychology Monographs, 87, 107–251.

Gombrich, E. H. (1972). Art and illusion: A study in thepsychology of pictorial representation. London, UK: Phai-don Press.

Goodnow, J. J. (1977). Children’s drawing. Cambridge,MA: Harvard University Press.

Guthrie, S. E. (1993). Faces in the clouds: A new theory ofreligion. New York, NY: Oxford University Press.

Hayashi, M. (2007). A new notation system of objectmanipulation in the nesting-cup task for chimpanzeesand humans. Cortex, 43, 308–318. doi:10.1007/s10071-009-0273-5

Hayashi, M., & Matsuzawa, T. (2003). Cognitive develop-ment in object manipulation by infant chimpanzees. Ani-mal Cognition, 6, 225–233. doi:10.1007/s10071-003-0185-8

Hayashi, M., Sekine, S., Tanaka, M., & Takeshita, H.(2009). Copying a model stack of colored blocks bychimpanzees and humans. Interaction Studies, 10, 130–149. doi:10.1075/is.10.2.03hay

Hayashi, M., & Takeshita, H. (2009). Stacking of irregu-larly shaped blocks in chimpanzees (Pan troglodytes)and young humans (Homo sapiens). Animal Cognition,12, 49–58. doi:10.1007/s10071-009-0273-5

Henshilwood, C. S., d’Errico, F., van Niekerk, K. L.,Coquinot, Y., Jacobs, Z., Lauritzen, S. E., . . . Garc�ıa-Moreno, R. (2011). A 100,000-year-old ochre-processingworkshop at Blombos Cave, South Africa. Science, 334,219–222. doi:10.1126/science.1211535

Henshilwood, C. S., d’Errico, F., & Watts, I. (2009).Engraved ochres from the Middle Stone Age levels atBlombos Cave, South Africa. Journal of Human Evolu-tion, 57, 27–47. doi:10.1016/j.jhevol.2009.01.005

Humphrey, N. (1998). Cave art, autism, and the evolutionof the human mind. Cambridge Archaeological Journal, 8,165–191.

Ikuzawa, M., Matsushita, Y., & Nakase, A. (1985). KyotoScale of Psychological Development [in Japanese]. Kyoto,Japan: Nakanishiya.

Imura, T., & Tomonaga, M. (2013). Differences betweenchimpanzees and humans in visual temporal integra-tion. Scientific Reports, 3, 3256. doi:10.1038/srep03256

Itakura, S. (1994). Recognition of line-drawing representa-tions by a chimpanzee (Pan troglodytes). Journal of Gen-eral Psychology, 121, 189–197. doi:10.1080/00221309.1994.9921195

Iversen, I. H., & Matsuzawa, T. (1996). Visually guideddrawing in the chimpanzee (Pan troglodytes). Japanese Psy-chological Research, 38, 126–135. doi:10.1111/j.1468-5884.1996.tb00017.x

Iversen, I. H., & Matsuzawa, T. (1997). Model-guided linedrawing in the chimpanzee (Pan troglodytes). JapanesePsychological Research, 39, 154–181. doi:10.1111/1468-5884.00051

Kellog, R. (1969). Analyzing children’s art. Palo Alto, CA:National Press Books.

Kellogg, W. N., & Kellogg, L. A. (1933). The ape and thechild: A study of environmental influence upon early behav-ior. New York, NY: McGraw-Hill.

Ladygina-Kohts, N. N. (2002). Infant chimpanzee andhuman child: A classic 1935 comparative study of ape emo-tions and intelligence. New York, NY: Oxford UniversityPress. (Original work published 1935)

Lenain, T. (1995). Ape-painting and the problem of theorigin of art. Human Evolution, 10, 205–215. doi:10.1007/BF02438973

Lenain, T. (1997). Monkey painting. London, UK: ReaktionBooks.

Luquet, G. H. (1927). Le dessin enfantin. Paris, France:Librairie F�elix Alcan.

Matsuzawa, T. (1985a). Color naming and classification ina chimpanzee (Pan troglodytes). Journal of Human Evolu-tion, 14, 283–291. doi:10.1016/S0047-2484(85)80069-5

Matsuzawa, T. (1985b). Use of numbers by a chimpanzee.Nature, 315, 57–59. doi:10.1038/315057a0

Matsuzawa, T. (1990). The world through the eyes of chim-panzees [in Japanese]. Tokyo, Japan: University ofTokyo Press.

Matsuzawa, T. (1995). Chimpanzees are “Chimpan-jin(human)” [in Japanese]. Tokyo, Japan: Iwanami Shoten.

Matsuzawa, T. (2000). Chimpanzee’s mind [in Japanese].Tokyo, Japan: Iwanami Shoten.

Matsuzawa, T. (2009). The chimpanzee mind: In search ofthe evolutionary roots of the human mind. Animal Cog-nition, 12, 1–9. doi:10.1007/s10071-009-0277-1

Matsuzawa, T., Biro, D., Humle, T., Inoue-Nakamura, N.,Tonooka, R., & Yamakoshi, G. (2001). Emergence ofculture in wild chimpanzees: Education by master-apprenticeship. In T. Matsuzawa (Ed.), Primate originsof human cognition and behavior (pp. 557–574). NewYork, NY: Springer. doi:10.1007/978-4-431-09423-4_28

Matthews, J. (1984). Children drawing: Are young chil-dren really scribbling? Early Child Development and Care,18, 1–39. doi:10.1080/0300443840180101


Morris, D. (1962). The biology of art. London, UK: MethuenYoung Books.

Myowa-Yamakoshi, M., & Matsuzawa, T. (1999). Fac-tors influencing imitation of manipulatory actions inchimpanzees (Pan troglodytes). Journal of ComparativePsychology, 113, 128–136. doi:10.1037/0735-7036.113.2.128

Patterson, F. (1986). The mind of the gorilla: Conversationand conservation. In K. Benirschke (Ed.), Primates: Theroad to self-sustaining populations. New York, NY:Springer-Verlag. doi:10.1007/978-1-4612-4918-4_63

Pike, A. W. G., Hoffmann, D. L., Garcia-Diez, M.,Pettitt, P. B., Alcolea, J., De Balbin, R., . . . Zilh€ao, J.(2012). U-Series dating of Paleolithic art in 11 cavesin Spain. Science, 336, 1409–1413. doi:10.1126/science.1219957

Premack, D. (1975). Putting a face together. Science, 188,228–236. doi:10.1126/science.1118724

Saito, A., Hayashi, M., Ueno, A., & Takeshita, H. (2011).Orientation-indifferent representation in children’sdrawings. Japanese Psychological Research, 53, 379–390.doi:10.1111/j.1468-5884.2011.00495.x

Schiller, P. H. (1951). Figural preferences in the drawingsof a chimpanzee. Journal of Comparative and PhysiologicalPsychology, 44, 101–111. doi:10.1037/h0053604

Smith, D. A. (1973). Systematic study of chimpanzeedrawing. Journal of Comparative and Physiological Psychol-ogy, 82, 406–414. doi:10.1037/h0034135

Takeshita, H. (2001). Development of combinatory manip-ulation in chimpanzee infants (Pan troglodytes). AnimalCognition, 4, 335–345. doi:10.1007/s100710100089

Takeshita, H., Myowa-Yamakoshi, M., & Hirata, S. (2009).The supine position of postnatal human infants: Impli-cations for the development of cognitive intelligence.Interaction Studies, 10, 252–268. doi:10.1075/is.10.2.08tak

Tanaka, M., Tomonaga, M., & Matsuzawa, T. (2003). Fingerdrawing by infant chimpanzees (Pan troglodytes). AnimalCognition, 6, 245–251. doi:10.1007/s10071-003-0198-3

Tomasello, M. (1999). The cultural origins of human cogni-tion. Cambridge, MA: Harvard University Press.

Yamagata, K. (1991). A study of scribbles on picturebooks by 1- and 2-year-old children [in Japanese]. Japa-nese Journal of Educational Psychology, 39, 102–110.

Yamagata, K. (2001). Emergence of representational activ-ity during the early drawing stage: Process analysis.Japanese Psychological Research, 43, 130–140. doi:10.1111/1468-5884.00169

Supporting Information

Additional supporting information may be found inthe online version of this article at the publisher’swebsite:

Appendix S1. The Criteria for Imitation inHumans, Modification of Ikuzawa et al. (1985)


Documents

The Origin of Representational Drawing: A Comparison of ......(1978) reported that chimpanzee Moja, who learned American Sign Language (ASL), signed on her drawings “bird” when