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Author Brosnan, S.F.; Freeman, C.; De Waal, F.B.M.
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 (up)
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 160
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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 (up)
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 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 (up)
Publisher Place of Publication 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 (up)
Publisher Place of Publication 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
Permanent link to this record
 
 
Author Brosnan, S.F.; De Waal, F.B.M.
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 (up)
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:13679918 Approved no
Call Number refbase @ user @ Serial 179
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Author de Waal, F.B.; Berger, M.L.
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 (up)
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title 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
Permanent link to this record
 
 
Author Friedrich, A.M.; Zentall, T.R.
Title Pigeons shift their preference toward locations of food that take more effort to obtain Type Journal Article
Year 2004 Publication Behavioural processes Abbreviated Journal Behav. Process.
Volume 67 Issue 3 Pages 405-415
Keywords Animals; *Behavior, Animal; *Choice Behavior; Columbidae; *Exertion; *Feeding Behavior; Reward
Abstract Although animals typically prefer to exert less effort rather than more effort to obtain food, the present research shows that requiring greater effort to obtain food at a particular location appears to increase the value of that location. In Experiment 1, pigeons' initial preference for one feeder was significantly reduced by requiring 1 peck to obtain food from that feeder and requiring 30 pecks to obtain food from the other feeder. In Experiment 2, a similar decrease in preference was not found when pigeons received reinforcement from both feeders independently of the amount of effort required. These results are consistent with the within-trial contrast effect proposed by in which the relative hedonic value of a reward depends on the state of the animal immediately prior to the reward. The greater the improvement from that prior state the greater the value of the reinforcer.
Address Department of Psychology, University of Kentucky, Lexington, KY 40506-0044, USA
Corporate Author Thesis (up)
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0376-6357 ISBN Medium
Area Expedition Conference
Notes PMID:15518990 Approved no
Call Number refbase @ user @ Serial 227
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Author Clement, T.S.; Feltus, J.R.; Kaiser, D.H.; Zentall, T.R.
Title “Work ethic” in pigeons: reward value is directly related to the effort or time required to obtain the reward Type Journal Article
Year 2000 Publication Psychonomic bulletin & review Abbreviated Journal Psychon Bull Rev
Volume 7 Issue 1 Pages 100-106
Keywords Animals; Behavior, Animal/*physiology; Cognition/physiology; Columbidae; Discrimination Learning/physiology; Female; Male; Reinforcement (Psychology); *Reward; Time Factors
Abstract Stimuli associated with less effort or with shorter delays to reinforcement are generally preferred over those associated with greater effort or longer delays to reinforcement. However, the opposite appears to be true of stimuli that follow greater effort or longer delays. In training, a simple simultaneous discrimination followed a single peck to an initial stimulus (S+FR1 S-FR1) and a different simple simultaneous discrimination followed 20 pecks to the initial stimulus (S+FR20 S-FR20). On test trials, pigeons preferred S+FR20 over S+FR1 and S-FR20 over S-FR1. These data support the view that the state of the animal immediately prior to presentation of the discrimination affects the value of the reinforcement that follows it. This contrast effect is analogous to effects that when they occur in humans have been attributed to more complex cognitive and social factors.
Address University of Kentucky, Lexington, USA
Corporate Author Thesis (up)
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-9384 ISBN Medium
Area Expedition Conference
Notes PMID:10780022 Approved no
Call Number refbase @ user @ Serial 248
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Author Sole, L.M.; Shettleworth, S.J.; Bennett, P.J.
Title Uncertainty in pigeons Type Journal Article
Year 2003 Publication Psychonomic bulletin & review Abbreviated Journal Psychon Bull Rev
Volume 10 Issue 3 Pages 738-745
Keywords Animals; Behavior, Animal; Columbidae; *Decision Making; Reinforcement (Psychology); Reward; Transfer (Psychology); Visual Perception
Abstract Pigeons classified a display of illuminated pixels on a touchscreen as sparse or dense. Correct responses were reinforced with six food pellets; incorrect responses were unreinforced. On some trials an uncertain response option was available. Pecking it was always reinforced with an intermediate number of pellets. Like monkeys and people in related experiments, the birds chose the uncertain response most often when the stimulus presented was difficult to classify correctly, but in other respects their behavior was not functionally similar to human behavior based on conscious uncertainty or to the behavior of monkeys in comparable experiments. Our data were well described by a signal detection model that assumed that the birds were maximizing perceived reward in a consistent way across all the experimental conditions.
Address University of Toronto, Toronto, Ontario, Canada
Corporate Author Thesis (up)
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-9384 ISBN Medium
Area Expedition Conference
Notes PMID:14620372 Approved no
Call Number refbase @ user @ Serial 366
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Author Johnson, D.D.P.; Stopka, P.; Knights, S.
Title Sociology: The puzzle of human cooperation Type Journal Article
Year 2003 Publication Nature Abbreviated Journal Nature
Volume 421 Issue 6926 Pages 911-2; discussion 912
Keywords Altruism; *Cooperative Behavior; Evolution; Humans; *Models, Biological; Punishment; Reward; Risk
Abstract
Address Olin Institute for Strategic Studies, Harvard University, Cambridge, Massachusetts 02138, USA. dominic@post.harvard.edu
Corporate Author Thesis (up)
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12606989 Approved no
Call Number refbase @ user @ Serial 467
Permanent link to this record