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Author Khalil, A.M.; Murakami, N.; Kaseda, Y.
Title Relationship between plasma testosterone concentrations and age, breeding season and harem size in Misaki feral horses Type Journal Article
Year 1998 Publication The Journal of veterinary medical science / the Japanese Society of Veterinary Science Abbreviated Journal J Vet Med Sci
Volume 60 Issue 5 Pages 643-645
Keywords Age Factors; Animals; Animals, Wild; *Horses; Japan; Male; Reproduction; Seasons; Sexual Behavior, Animal; Sexual Maturation; *Social Behavior; Testosterone/*blood
Abstract Jugular vein blood samples were collected from 23 young and sexual mature feral stallions to examine the relationship between plasma testosterone concentration and age, breeding season or harem size. Testosterone concentration increased with the age of the stallions until they formed their own harems, at about 4 to 6 years old. Seasonal variations in testosterone concentrations were observed, and found to be significantly higher (P<0.001) throughout the breeding season than non-breeding season, from 3 years of age. Testosterone levels were correlated with harem size for individual stallions. It can be inferred from these results that there is a relationship between plasma testosterone concentration and age, breeding season and harem size.
Address Laboratory of Animal Behavioral Science, Faculty of Agriculture, Miyazaki University, Japan
Corporate Author Thesis
Publisher Place of Publication (up) Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0916-7250 ISBN Medium
Area Expedition Conference
Notes PMID:9637303 Approved no
Call Number refbase @ user @ Serial 137
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Author Bonnie, K.E.; de Waal, F.B.M.
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
Publisher Place of Publication (up) 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:16142425 Approved no
Call Number refbase @ user @ Serial 161
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Author de Waal, F.B.M.
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 (up) 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 162
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Author Flack, J.C.; Krakauer, D.C.; de Waal, F.B.M.
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
Publisher Place of Publication (up) Editor
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 165
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Author Brosnan, S.F.; de Waal, F.B.M.
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 (up) 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 167
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Author Brosnan, S.F.; Schiff, H.C.; de Waal, F.B.M.
Title Tolerance for inequity may increase with social closeness in chimpanzees Type Journal Article
Year 2005 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 272 Issue 1560 Pages 253-258
Keywords Analysis of Variance; Animals; *Attitude; Group Processes; Pan troglodytes/*psychology; Reward; *Social Behavior; Socioeconomic Factors
Abstract Economic decision-making depends on our social environment. Humans tend to respond differently to inequity in close relationships, yet we know little about the potential for such variation in other species. We examine responses to inequity in several groups of chimpanzees (Pan troglodytes) in a paradigm similar to that used previously in capuchin monkeys (Cebus apella). We demonstrate that, like capuchin monkeys, chimpanzees show a response to inequity of rewards that is based upon the partner receiving the reward rather than the presence of the reward alone. However, we also found a great amount of variation between groups tested, indicating that chimpanzees, like people, respond to inequity in a variable manner, which we speculate could be caused by such variables as group size, the social closeness of the group (as reflected in length of time that the group has been together) and group-specific traditions.
Address Yerkes National Primate Research Center, Emory University, 954 North Gatewood Drive, Atlanta, GA 30329, USA. sbrosna@emory.edu
Corporate Author Thesis
Publisher Place of Publication (up) Editor
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:15705549 Approved no
Call Number refbase @ user @ Serial 169
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Author Brosnan, S.F.; de Waal, F.B.M.
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 (up) Editor
Language English Summary Language Original Title
Series Editor Series Title 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 Weaver, A.; de Waal, F.B.M.
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 (up) Editor
Language English Summary Language Original Title
Series Editor Series Title 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.
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 (up) Editor
Language English Summary Language Original Title
Series Editor Series Title 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 Lilienfeld, S.O.; Gershon, J.; Duke, M.; Marino, L.; de Waal, F.B.
Title A preliminary investigation of the construct of psychopathic personality (psychopathy) in chimpanzees (Pan troglodytes) Type Journal Article
Year 1999 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol
Volume 113 Issue 4 Pages 365-375
Keywords Age Factors; Analysis of Variance; Animals; Antisocial Personality Disorder/*diagnosis/psychology; Ethology/*methods; Female; Male; Observer Variation; Pan troglodytes/*psychology; Psychiatric Status Rating Scales/*standards; Reproducibility of Results; Sex Characteristics; *Social Behavior
Abstract Although the construct of psychopathy has received considerable attention in humans, its relevance to other animals is largely unknown. We developed a measure of psychopathy for use in chimpanzees (Pan troglodytes), the Chimpanzee Psychopathy Measure (CPM), and asked 6 raters to complete this index on 34 chimpanzees. The CPM (a) demonstrated satisfactory interrater reliability and internal consistency; (b) exhibited marginally significant sex differences (males > females); (c) correlated positively with measures of extraversion, agreeableness, and observational ratings of agonism, sexual activity, daring behaviors, teasing, silent bluff displays, and temper tantrums, and negatively with observational ratings of generosity; and (d) demonstrated incremental validity above and beyond a measure of dominance. Although further validation of the CPM is needed, these findings suggest that the psychopathy construct may be relevant to chimpanzees.
Address Department of Psychology, Emory University, Atlanta, Georgia 30322, USA. scott@ss.emory.edu
Corporate Author Thesis
Publisher Place of Publication (up) Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0735-7036 ISBN Medium
Area Expedition Conference
Notes PMID:10608560 Approved no
Call Number refbase @ user @ Serial 193
Permanent link to this record