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Author Dindo, M.; De Waal, F.B.M. doi  openurl
  Title Partner effects on food consumption in brown capuchin monkeys Type Journal Article
  Year 2007 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 69 Issue 4 Pages 448-456  
  Keywords  
  Abstract It has been claimed that capuchin monkeys (Cebus apella) show inequity aversion in relation to food rewards for a simple exchange task. However, other factors may affect the willingness of a monkey to consume foods of high or low value in the presence of a conspecific. In this study, pairs of monkeys were presented with unequally valued foods, but without any task-performance: they simply received the food under four experimental conditions. By looking at the rate of collection and consumption of low-valued cucumber slices we expected to see variation dependent on whether the partner either had 1) cucumber (equity), 2) grape (inequity), 3) inaccessible cucumber or 4) inaccessible grape. Testing 12 adult capuchin monkeys, our findings differed from those of other authors in that the monkeys failed to show negative reactions to inequity, but rather responded with scramble competition (i.e., fast food collection) in the presence of a conspecific without access to food. They also showed facilitated consumption in the presence of a conspecific consuming high-valued food. Possibly, (in)equity plays a different role if food serves as a reward for a task rather than if it is simply made available for consumption. Am. J. Primatol. 69:1-9, 2007. (c) 2006 Wiley-Liss, Inc.  
  Address Living Links, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17146793 Approved no  
  Call Number refbase @ user @ Serial (up) 158  
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Author Horner, V.; Whiten, A.; Flynn, E.; de Waal, F.B.M. doi  openurl
  Title Faithful replication of foraging techniques along cultural transmission chains by chimpanzees and children Type Journal Article
  Year 2006 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 103 Issue 37 Pages 13878-13883  
  Keywords Animals; Child, Preschool; Humans; *Imitative Behavior; Pan troglodytes/*psychology  
  Abstract Observational studies of wild chimpanzees (Pan troglodytes) have revealed population-specific differences in behavior, thought to represent cultural variation. Field studies have also reported behaviors indicative of cultural learning, such as close observation of adult skills by infants, and the use of similar foraging techniques within a population over many generations. Although experimental studies have shown that chimpanzees are able to learn complex behaviors by observation, it is unclear how closely these studies simulate the learning environment found in the wild. In the present study we have used a diffusion chain paradigm, whereby a behavior is passed from one individual to the next in a linear sequence in an attempt to simulate intergenerational transmission of a foraging skill. Using a powerful three-group, two-action methodology, we found that alternative methods used to obtain food from a foraging device (“lift door” versus “slide door”) were accurately transmitted along two chains of six and five chimpanzees, respectively, such that the last chimpanzee in the chain used the same method as the original trained model. The fidelity of transmission within each chain is remarkable given that several individuals in the no-model control group were able to discover either method by individual exploration. A comparative study with human children revealed similar results. This study is the first to experimentally demonstrate the linear transmission of alternative foraging techniques by non-human primates. Our results show that chimpanzees have a capacity to sustain local traditions across multiple simulated generations.  
  Address Centre for Social Learning and Cognitive Evolution, School of Psychology, University of St. Andrews, Fife KY16 9JP, United Kingdom  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16938863 Approved no  
  Call Number refbase @ user @ Serial (up) 159  
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Author Brosnan, S.F.; Freeman, C.; De Waal, F.B.M. doi  openurl
  Title Partner's behavior, not reward distribution, determines success in an unequal cooperative task in capuchin monkeys Type Journal Article
  Year 2006 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 68 Issue 7 Pages 713-724  
  Keywords Animals; Behavior, Animal/*physiology; Cebus/*physiology; *Cooperative Behavior; Female; Food Preferences/physiology; Male; *Reward  
  Abstract It was recently demonstrated that capuchin monkeys notice and respond to distributional inequity, a trait that has been proposed to support the evolution of cooperation in the human species. However, it is unknown how capuchins react to inequitable rewards in an unrestricted cooperative paradigm in which they may freely choose both whether to participate and, within the bounds of their partner's behavior, which reward they will receive for their participation. We tested capuchin monkeys with such a design, using a cooperative barpull, which has been used with great success in the past. Contrary to our expectations, the equity of the reward distribution did not affect success or pulling behavior. However, the behavior of the partner in an unequal situation did affect overall success rates: pairs that had a tendency to alternate which individual received the higher-value food in unequal reward situations were more than twice as successful in obtaining rewards than pairs in which one individual dominated the higher-value food. This ability to equitably distribute rewards in inherently biased cooperative situations has profound implications for activities such as group hunts, in which multiple individuals work together for a single, monopolizable reward.  
  Address Living Links Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA. sbrosna@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16786518 Approved no  
  Call Number refbase @ user @ Serial (up) 160  
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Author Bonnie, K.E.; de Waal, F.B.M. doi  openurl
  Title Affiliation promotes the transmission of a social custom: handclasp grooming among captive chimpanzees Type Journal Article
  Year 2006 Publication Primates Abbreviated Journal Primates  
  Volume 47 Issue 1 Pages 27-34  
  Keywords Animals; Animals, Zoo/*physiology; Behavior, Animal/*physiology; *Cultural Evolution; Grooming/*physiology; Observation; Pan troglodytes/*physiology; *Social Behavior  
  Abstract Handclasp grooming is a unique social custom, known to occur regularly among some, but not all populations of chimpanzees (Pan troglodytes). As with other cultural behaviors, it is assumed that this distinctive grooming posture is learned socially by one individual from another. However, statistical comparisons among factors thought to influence how a behavior spreads within a group have never, to our knowledge, been conducted. In the present study, the origination and spread of handclasp grooming in a group of captive chimpanzees was followed throughout more than 1,500 h of observation over a period of 12 years. We report on the frequency, bout duration, and number and demography of performers throughout the study period, and compare these findings to those reported for wild populations. We predicted that dyads with strong affiliative ties, measured by time spent in proximity to and grooming one another, were likely to develop a handclasp grooming partnership during the study period. A quadratic assignment procedure was used to compare correlations among observed frequencies of grooming and proximity with handclasp grooming in all possible dyads within the group. As predicted, the formation of new handclasp grooming dyads was positively correlated with the rate of overall grooming and proximity within a dyad. In addition, in nearly all dyads formed, at least one individual had been previously observed to handclasp groom. We concluded that affiliation and individual experience determines the transmission of handclasp grooming among captive chimpanzees.  
  Address Department of Psychology, Emory University, and Living Links Center, Yerkes National Primate Research Center, GA 30329, USA. kebonni@emory.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0032-8332 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16142425 Approved no  
  Call Number refbase @ user @ Serial (up) 161  
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Author de Waal, F.B.M. doi  openurl
  Title A century of getting to know the chimpanzee Type Journal Article
  Year 2005 Publication Nature Abbreviated Journal Nature  
  Volume 437 Issue 7055 Pages 56-59  
  Keywords Aggression; Animals; Behavior, Animal/*physiology; Competitive Behavior; Cooperative Behavior; Female; Humans; Male; Pan troglodytes/genetics/*physiology/psychology; Sexual Behavior, Animal; *Social Behavior  
  Abstract A century of research on chimpanzees, both in their natural habitat and in captivity, has brought these apes socially, emotionally and mentally much closer to us. Parallels and homologues between chimpanzee and human behaviour range from tool-technology and cultural learning to power politics and intercommunity warfare. Few behavioural domains have remained untouched by this increased knowledge, which has dramatically challenged the way we view ourselves. The sequencing of the chimpanzee genome will no doubt bring more surprises and insights. Humans do occupy a special place among the primates, but this place increasingly has to be defined against a backdrop of substantial similarity.  
  Address Living Links, Yerkes National Primate Research Center, Emory University, 954 North Gatewood Road, Atlanta, Georgia 30322, USA. dewaal@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16136128 Approved no  
  Call Number refbase @ user @ Serial (up) 162  
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Author Whiten, A.; Horner, V.; de Waal, F.B.M. doi  openurl
  Title Conformity to cultural norms of tool use in chimpanzees Type Journal Article
  Year 2005 Publication Nature Abbreviated Journal Nature  
  Volume 437 Issue 7059 Pages 737-740  
  Keywords Aging/physiology; Animals; Culture; Feeding Behavior/physiology; Female; Pan troglodytes/*physiology/*psychology; *Social Conformity; Technology; Time Factors  
  Abstract Rich circumstantial evidence suggests that the extensive behavioural diversity recorded in wild great apes reflects a complexity of cultural variation unmatched by species other than our own. However, the capacity for cultural transmission assumed by this interpretation has remained difficult to test rigorously in the field, where the scope for controlled experimentation is limited. Here we show that experimentally introduced technologies will spread within different ape communities. Unobserved by group mates, we first trained a high-ranking female from each of two groups of captive chimpanzees to adopt one of two different tool-use techniques for obtaining food from the same 'Pan-pipe' apparatus, then re-introduced each female to her respective group. All but two of 32 chimpanzees mastered the new technique under the influence of their local expert, whereas none did so in a third population lacking an expert. Most chimpanzees adopted the method seeded in their group, and these traditions continued to diverge over time. A subset of chimpanzees that discovered the alternative method nevertheless went on to match the predominant approach of their companions, showing a conformity bias that is regarded as a hallmark of human culture.  
  Address Centre for Social Learning and Cognitive Evolution, School of Psychology, University of St Andrews, St Andrews, Fife, KY16 9JP, UK. a.whiten@st-and.ac.uk  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16113685 Approved no  
  Call Number refbase @ user @ Serial (up) 163  
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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  
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  Language English Summary Language Original Title  
  Series Editor Series Title 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 (up) 164  
Permanent link to this record
 

 
Author Flack, J.C.; Krakauer, D.C.; de Waal, F.B.M. doi  openurl
  Title Robustness mechanisms in primate societies: a perturbation study Type Journal Article
  Year 2005 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 272 Issue 1568 Pages 1091-1099  
  Keywords Aggression/physiology; Animals; *Conflict (Psychology); Female; *Hierarchy, Social; Macaca nemestrina/*physiology; Male; *Models, Theoretical; Observation; *Social Behavior  
  Abstract Conflict management mechanisms have a direct, critical effect on system robustness because they mitigate conflict intensity and help repair damaged relationships. However, robustness mechanisms can also have indirect effects on system integrity by facilitating interactions among components. We explore the indirect role that conflict management mechanisms play in the maintenance of social system robustness, using a perturbation technique to 'knockout' components responsible for effective conflict management. We explore the effects of knockout on pigtailed macaque (Macaca nemestrina) social organization, using a captive group of 84 individuals. This system is ideal in addressing this question because there is heterogeneity in performance of conflict management. Consequently, conflict managers can be easily removed without disrupting other control structures. We find that powerful conflict managers are essential in maintaining social order for the benefit of all members of society. We show that knockout of components responsible for conflict management results in system destabilization by significantly increasing mean levels of conflict and aggression, decreasing socio-positive interaction and decreasing the operation of repair mechanisms.  
  Address Santa Fe Institute, NM 87501, USA. jflack@santafe.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16024369 Approved no  
  Call Number refbase @ user @ Serial (up) 165  
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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 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 (up) 166  
Permanent link to this record
 

 
Author Brosnan, S.F.; de Waal, F.B.M. doi  openurl
  Title Responses to a simple barter task in chimpanzees, Pan troglodytes Type Journal Article
  Year 2005 Publication Primates Abbreviated Journal Primates  
  Volume 46 Issue 3 Pages 173-182  
  Keywords Analysis of Variance; Animals; Choice Behavior/*physiology; Conditioning (Psychology)/physiology; Learning/*physiology; Pan troglodytes/*physiology; Reward; Sex Factors; *Social Behavior; *Token Economy  
  Abstract Chimpanzees (Pan troglodytes) frequently participate in social exchange involving multiple goods and services of variable value, yet they have not been tested in a formalized situation to see whether they can barter using multiple tokens and rewards. We set up a simple barter economy with two tokens and two associated rewards and tested chimpanzees on their ability to obtain rewards by returning the matching token in situations in which their access to tokens was unlimited or limited. Chimpanzees easily learned to associate value with the tokens, as expected, and did barter, but followed a simple strategy of favoring the higher-value token, regardless of the reward proffered, instead of a more complex but more effective strategy of returning the token that matched the reward. This response is similar to that shown by capuchin monkeys in our previous study. We speculate that this response, while not ideal, may be sufficient to allow for stability of the social exchange system in these primates, and that the importance of social barter to both species may have led to this convergence of strategies.  
  Address Living Links, Yerkes National Primate Research Center, Atlanta, GA 30322, USA. sbrosna@emory.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0032-8332 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15824938 Approved no  
  Call Number refbase @ user @ Serial (up) 167  
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