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Author de Waal, F.B.M.; Dindo, M.; Freeman, C.A.; Hall, M.J. doi  openurl
  Title The monkey in the mirror: hardly a stranger Type Journal Article
  Year 2005 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 102 Issue 32 Pages 11140-11147  
  Keywords Analysis of Variance; Animals; Cebus/*physiology; *Discrimination (Psychology); Empathy; Female; Male; Observation; *Recognition (Psychology); *Self Concept; Sex Factors  
  Abstract It is widely assumed that monkeys see a stranger in the mirror, whereas apes and humans recognize themselves. In this study, we question the former assumption by using a detailed comparison of how monkeys respond to mirrors versus live individuals. Eight adult female and six adult male brown capuchin monkeys (Cebus apella) were exposed twice to three conditions: (i) a familiar same-sex partner, (ii) an unfamiliar same-sex partner, and (iii) a mirror. Females showed more eye contact and friendly behavior and fewer signs of anxiety in front of a mirror than they did when exposed to an unfamiliar partner. Males showed greater ambiguity, but they too reacted differently to mirrors and strangers. Discrimination between conditions was immediate, and blind coders were able to tell the difference between monkeys under the three conditions. Capuchins thus seem to recognize their reflection in the mirror as special, and they may not confuse it with an actual conspecific. Possibly, they reach a level of self-other distinction intermediate between seeing their mirror image as other and recognizing it as self.  
  Address Living Links Center, Emory University, Atlanta, GA 30322, USA. dewaal@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16055557 Approved no  
  Call Number refbase @ user @ Serial 164  
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Author de Waal, F.B.M. openurl 
  Title How animals do business Type Journal Article
  Year 2005 Publication Scientific American Abbreviated Journal Sci Am  
  Volume 292 Issue 4 Pages 54-61  
  Keywords Animals; Attitude; *Behavior, Animal; Cebus; Cooperative Behavior; *Economics; Emotions; Fishes; Food; Humans; Pan troglodytes; Papio; Social Behavior  
  Abstract  
  Address Emory University, USA  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8733 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15915815 Approved no  
  Call Number refbase @ user @ Serial 166  
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Author Brosnan, S.F.; de Waal, F.B.M. doi  openurl
  Title A concept of value during experimental exchange in brown capuchin monkeys, Cebus apella Type Journal Article
  Year 2004 Publication Folia primatologica; international journal of primatology Abbreviated Journal Folia Primatol (Basel)  
  Volume 75 Issue 5 Pages 317-330  
  Keywords Animals; Cebus/*psychology; *Choice Behavior; Female; Food Preferences; *Learning; Male; Sex Factors; Statistics, Nonparametric; *Token Economy; Video Recording  
  Abstract We evaluated the response of brown capuchin monkeys to two differentially valued tokens in an experimental exchange situation akin to a simple barter. Monkeys were given a series of three tests to evaluate their ability to associate tokens with food, then their responses were examined in a barter situation in which tokens were either limited or unlimited. Capuchins did not perform barter in the typical sense, returning the tokens which were associated with the reward. However, females, but not males, showed a different response, preferring the higher-value token. This may indicate that they learned to prefer one token over the other rather than to associate the tokens with their specific rewards. This sex difference parallels previous findings of greater reciprocity in female brown capuchins than in males.  
  Address Living Links Center, Emory University, Yerkes National Primate Research Center, 954 N. Gatewood Drive, Atlanta, GA 30329, USA. sbrosna@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0015-5713 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15486443 Approved no  
  Call Number refbase @ user @ Serial 170  
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Author Brosnan, S.F.; de Waal, F.B.M. doi  openurl
  Title Socially learned preferences for differentially rewarded tokens in the brown capuchin monkey (Cebus apella) Type Journal Article
  Year 2004 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 118 Issue 2 Pages 133-139  
  Keywords Animals; Behavior, Animal; Cebus; *Choice Behavior; Female; *Learning; Male; *Reward; *Social Behavior  
  Abstract Social learning is assumed to underlie traditions, yet evidence indicating social learning in capuchin monkeys (Cebus apella), which exhibit traditions, is sparse. The authors tested capuchins for their ability to learn the value of novel tokens using a previously familiar token-exchange economy. Capuchins change their preferences in favor of a token worth a high-value food reward after watching a conspecific model exchange 2 differentially rewarded tokens, yet they fail to develop a similar preference after watching tokens paired with foods in the absence of a conspecific model. They also fail to learn that the value of familiar tokens has changed. Information about token value is available in all situations, but capuchins seem to pay more attention in a social situation involving novel tokens.  
  Address Living Links Center, Yerkes National Primate Research Center, and Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30329, USA. sbrosna@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15250800 Approved no  
  Call Number refbase @ user @ Serial 173  
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Author Brosnan, S.F.; De Waal, F.B.M. doi  openurl
  Title Monkeys reject unequal pay Type Journal Article
  Year 2003 Publication Nature Abbreviated Journal Nature  
  Volume 425 Issue 6955 Pages 297-299  
  Keywords Aging; Animals; Cebus/*psychology; Choice Behavior; *Cooperative Behavior; Female; Male; *Reward; Social Justice  
  Abstract During the evolution of cooperation it may have become critical for individuals to compare their own efforts and pay-offs with those of others. Negative reactions may occur when expectations are violated. One theory proposes that aversion to inequity can explain human cooperation within the bounds of the rational choice model, and may in fact be more inclusive than previous explanations. Although there exists substantial cultural variation in its particulars, this 'sense of fairness' is probably a human universal that has been shown to prevail in a wide variety of circumstances. However, we are not the only cooperative animals, hence inequity aversion may not be uniquely human. Many highly cooperative nonhuman species seem guided by a set of expectations about the outcome of cooperation and the division of resources. Here we demonstrate that a nonhuman primate, the brown capuchin monkey (Cebus apella), responds negatively to unequal reward distribution in exchanges with a human experimenter. Monkeys refused to participate if they witnessed a conspecific obtain a more attractive reward for equal effort, an effect amplified if the partner received such a reward without any effort at all. These reactions support an early evolutionary origin of inequity aversion.  
  Address Living Links, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30329, USA. sbrosna@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:13679918 Approved no  
  Call Number refbase @ user @ Serial 179  
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Author Weaver, A.; de Waal, F.B.M. openurl 
  Title The mother-offspring relationship as a template in social development: reconciliation in captive brown capuchins (Cebus apella) Type Journal Article
  Year 2003 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 117 Issue 1 Pages 101-110  
  Keywords *Adaptation, Psychological; Animals; Behavior, Animal/*physiology; Cebus; Conflict (Psychology); Female; Male; *Maternal Behavior; Pilot Projects; *Social Behavior; Statistics, Nonparametric  
  Abstract Mother-offspring (MO) relationship quality was investigated to determine its influence on the development of reconciliation--affiliation between opponents shortly after a fight--because it influenceswhat distressed youngsters learn about calming down. Data were longitudinal and cross-sectional observational samples of 38 MO pairs of monkeys across 24 months. An MO relationship quality index (RQI) classified each pair as secure or insecure. Reconciliation emerged in infancy.Secure youngsters had an appeasing conciliatory style, and insecure youngsters had an agitated conciliatory style. Conclusions are that reconciliation develops from the attachment behavior system and MO RQI is related to the particular conciliatory style youngsters develop by affecting how aroused they are by conflict and the subsequent socializing they seek to calm down.  
  Address Living Links, Yerkes Primate Center and Psychology Department, Emory University, Atlanta, Georgia 30322, USA. dazzlingdolphins@cox.net  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12735370 Approved no  
  Call Number refbase @ user @ Serial 180  
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Author de Waal, F.B.M.; Davis, J.M. openurl 
  Title Capuchin cognitive ecology: cooperation based on projected returns Type Journal Article
  Year 2003 Publication Neuropsychologia Abbreviated Journal Neuropsychologia  
  Volume 41 Issue 2 Pages 221-228  
  Keywords Animals; Attention; Cebus/*psychology; *Cooperative Behavior; Decision Making; Dominance-Subordination; Female; Male; *Motivation; Reaction Time; Reinforcement Schedule; *Social Behavior  
  Abstract Stable cooperation requires that each party's pay-offs exceed those available through individual action. The present experimental study on brown capuchin monkeys (Cebus apella) investigated if decisions about cooperation are (a) guided by the amount of competition expected to follow the cooperation, and (b) made instantaneously or only after a period of familiarization. Pairs of adult monkeys were presented with a mutualistic cooperative task with variable opportunities for resource monopolization (clumped versus dispersed rewards), and partner relationships (kin versus nonkin). After pre-training, each pair of monkeys (N=11) was subjected to six tests, consisting of 15 2 min trials each, with rewards available to both parties. Clumped reward distribution had an immediate negative effect on cooperation: this effect was visible right from the start, and remained visible even if clumped trials alternated with dispersed trials. The drop in cooperation was far more dramatic for nonkin than kin, which was explained by the tendency of dominant nonkin to claim more than half of the rewards under the clumped condition. The immediacy of responses suggests a decision-making process based on predicted outcome of cooperation. Decisions about cooperation thus take into account both the opportunity for and the likelihood of subsequent competition over the spoils.  
  Address Living Links, Yerkes Primate Center, Emory University, 954 N. Gatewood Road, Atlanta, GA 30322, USA. dewaal@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-3932 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12459220 Approved no  
  Call Number refbase @ user @ Serial 182  
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Author de Waal, F.B.; Berger, M.L. doi  openurl
  Title Payment for labour in monkeys Type Journal Article
  Year 2000 Publication Nature Abbreviated Journal Nature  
  Volume 404 Issue 6778 Pages 563  
  Keywords Animals; Cebus/*physiology; *Cooperative Behavior; Evolution; *Feeding Behavior; Female; Male; Reward  
  Abstract  
  Address Living Links, Yerkes Regional Primate Research Center, and Department of Psychology, Emory University, Atlanta, Georgia 30329, USA. dewaal@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10766228 Approved no  
  Call Number refbase @ user @ Serial 190  
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Author de Waal, F.B. openurl 
  Title Food transfers through mesh in brown capuchins Type Journal Article
  Year 1997 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 111 Issue 4 Pages 370-378  
  Keywords Animals; Cebus/*psychology; *Feeding Behavior; Female; Food Preferences/psychology; Male; *Motivation; Sex Factors; *Social Behavior; Social Environment  
  Abstract Capuchin monkeys (Cebus apella) share food even if their partner is behind a mesh restraint. Pairs of adult capuchins were moved into a test chamber in which 1 monkey received cucumber pieces for 20 min and the other received apple slices during the following 20 min. Tolerant transfers of food occurred reciprocally among females: The rate of transfer from Female B to A in the second test phase varied with the rate from Female A to B in the first test phase. Several social mechanisms may explain this reciprocity. Whereas this study does not contradict cognitively complex explanations (e.g., mental record keeping of given and received food), the results are consistent with a rather simple explanation: that food sharing reflects a combination of affiliative tendency and high tolerance. The study suggests that sharing mechanisms may be different for adult male capuchins, with males sharing food more readily and less discriminatingly than females.  
  Address Yerkes Primate Center, Emory University, Atlanta, Georgia 30329, USA. dewaal@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9419882 Approved no  
  Call Number refbase @ user @ Serial 198  
Permanent link to this record
 

 
Author Parr, L.A.; Hopkins, W.D.; de Waal, F.B. openurl 
  Title Haptic discrimination in capuchin monkeys (Cebus apella): evidence of manual specialization Type Journal Article
  Year 1997 Publication Neuropsychologia Abbreviated Journal Neuropsychologia  
  Volume 35 Issue 2 Pages 143-152  
  Keywords Aging/psychology; Animals; Cebus; Cues; Discrimination (Psychology)/*physiology; Female; Functional Laterality/*physiology; Male; Psychomotor Performance/physiology; Sex Characteristics; Touch/physiology  
  Abstract Two experiments investigated the effects of haptic and visual discrimination on hand preference in 22 brown capuchin monkeys (Cebus apella). The percentage of left-handed subjects in Experiment 1 were 63.6%, 45.5%, and 18.2% for haptic, bipedal, and quadrupedal reaching, respectively. In Experiment 2, the haptic demands of the task were manipulated by using additional food types and another tactile medium. Left-hand preferences were further strengthened when reaching into water compared to pineshavings in Experiment 1. Reaching with no tactile interference resulted in equal numbers of lateralized and nonlateralized subjects. These results show that when reaching demands the use of haptic cues, as opposed to visual ones, monkeys shift towards greater left hand use. This is consistent with what is known about right hemisphere superiority for haptic discrimination in humans.  
  Address Division of Psychobiology, Yerkes Regional Primate Research Center, Atlanta, GA 30329, USA. parr@rmy.-emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title (up) Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-3932 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9025118 Approved no  
  Call Number refbase @ user @ Serial 201  
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