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Author Brosnan, S.F.; de Waal, F.B.M.
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 (down) 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.
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 (down) 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.
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 (down) 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 Martin, T.I.; Zentall, T.R.
Title Post-choice information processing by pigeons Type Journal Article
Year 2005 Publication Animal cognition Abbreviated Journal Anim. Cogn.
Volume 8 Issue 4 Pages 273-278
Keywords Animals; *Behavior, Animal; *Choice Behavior; *Columbidae; Discrimination Learning
Abstract In a conditional discrimination (matching-to-sample), a sample is followed by two comparison stimuli, one of which is correct, depending on the sample. Evidence from previous research suggests that if the stimulus display is maintained following an incorrect response (the so-called penalty-time procedure), acquisition by pigeons is facilitated. The present research tested the hypothesis that the penalty-time procedure allows the pigeons to review and learn from the maintained stimulus display following an incorrect choice. It did so by including a penalty-time group for which, following an incorrect choice, the sample changed to match the incorrect comparison, thus providing the pigeons with post-choice 'misinformation.' This misinformation group acquired the matching task significantly slower than the standard penalty-time group (that had no change in the sample following an error). Furthermore, acquisition of matching by a control group that received no penalty time fell midway between the other two groups, suggesting that the pigeons did not merely take more care in making choices because of the aversiveness of penalty-time. Thus, it appears that in the acquisition of matching-to-sample, when the stimulus display is maintained following an incorrect choice, the pigeons can review or acquire information from the display. This is the first time that such an effect has been reported for a nonhuman species.
Address Department of Psychology, University of Kentucky, Lexington, KY 40506, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1435-9448 ISBN Medium
Area Expedition Conference
Notes PMID:15744507 Approved no
Call Number refbase @ user @ Serial 225
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Author DiGian, K.A.; Friedrich, A.M.; Zentall, T.R.
Title Discriminative stimuli that follow a delay have added value for pigeons Type Journal Article
Year 2004 Publication Psychonomic bulletin & review Abbreviated Journal Psychon Bull Rev
Volume 11 Issue 5 Pages 889-895
Keywords Animals; Behavior, Animal; Choice Behavior; Columbidae; *Cues; *Discrimination (Psychology)
Abstract Clement, Feltus, Kaiser, and Zentall (2000) reported that pigeons prefer discriminative stimuli that require greater effort (more pecks) to obtain over those that require less effort. In the present experiment, we examined two variables associated with this phenomenon. First, we asked whether delay of reinforcement, presumably a relatively aversive event similar to effort, would produce similar effects. Second, we asked whether the stimulus preference produced by a prior relatively aversive event depends on its anticipation. Anticipation of delay was accomplished by signaling its occurrence. Results indicated that delays can produce preferences similar to those produced by increased effort, but only if the delays are signaled.
Address University of Kentucky, Lexington, Kentucky 40506-0044, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-9384 ISBN Medium
Area Expedition Conference
Notes PMID:15732699 Approved no
Call Number refbase @ user @ Serial 226
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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
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) 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.; Zentall, T.R.
Title Choice based on exclusion in pigeons Type Journal Article
Year 2003 Publication Psychonomic bulletin & review Abbreviated Journal Psychon Bull Rev
Volume 10 Issue 4 Pages 959-964
Keywords Animals; Appetitive Behavior; *Association Learning; *Choice Behavior; *Color Perception; Columbidae; *Discrimination Learning; Memory, Short-Term; *Problem Solving; Psychomotor Performance; Reaction Time; Transfer (Psychology)
Abstract When humans acquire a conditional discrimination and are given a novel-sample-comparison choice, they often reject a comparison known to be associated with a different sample and choose the alternative comparison by default (or by exclusion). In Experiment 1, we found that if, following matching training, we replaced both of the samples, acquisition took five times longer than if we replaced only one of the samples. Apparently, the opportunity to reject one of the comparisons facilitated the association of the other sample with the remaining comparison. In Experiment 2, we first trained pigeons to treat two samples differently (to associate Sample A with Comparison 1 and Sample B with Comparison 2) and then trained them to associate one of those samples with a new comparison (e.g., Sample A with Comparison 3) and to associate a novel sample (Sample C) with a different, new comparison (Comparison 4). When Sample B then replaced Sample C, the pigeons showed a significant tendency to choose Comparison 4 over Comparison 3. Thus, when given the opportunity, pigeons will choose by exclusion.
Address University of Kentucky, Lexington, Kentucky, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-9384 ISBN Medium
Area Expedition Conference
Notes PMID:15000545 Approved no
Call Number refbase @ user @ Serial 233
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Author Zentall, T.R.; Kaiser, D.H.; Clement, T.S.; Weaver, J.E.; Campbell, G.
Title Presence/absence-sample matching by pigeons: divergent retention functions may result from the similarity of behavior during the absence sample and the retention interval Type Journal Article
Year 2000 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 26 Issue 3 Pages 294-304
Keywords Analysis of Variance; Animals; *Behavior, Animal; *Choice Behavior; *Columbidae; *Conditioning, Operant; Cues
Abstract Divergent choose-absence retention functions typically found in pigeons following presence/absence-sample matching have been attributed to the development of a single-code/default coding strategy. However, such effects may result from adventitious differential responding to the samples. In Experiment 1, retention functions were divergent only when differential sample responding could serve as the basis for comparison choice. In Experiment 2, when pecking did not occur during the retention interval, a choose-absence bias was found, but when pecking occurred during the retention interval, a choose-presence bias resulted. In Experiment 3, positive transfer was found when a stimulus associated with the absence of pecking replaced the absence sample but not when a stimulus associated with pecking replaced the presence sample. Thus, presence/absence-sample matching may not encourage the development of a single-code/default coding strategy in pigeons.
Address Department of Psychology, University of Kentucky, Lexington 40506, USA. zentall@pop.uky.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0097-7403 ISBN Medium
Area Expedition Conference
Notes PMID:10913994 Approved no
Call Number refbase @ user @ Serial 247
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Author Zentall, T.R.; Sherburne, L.M.
Title Role of differential sample responding in the differential outcomes effect involving delayed matching by pigeons Type Journal Article
Year 1994 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 20 Issue 4 Pages 390-401
Keywords Animals; Behavior, Animal; Choice Behavior; *Columbidae; *Discrimination Learning; Feeding Behavior; Task Performance and Analysis
Abstract The role of differential sample responding in the differential outcomes effect was examined. In Experiment 1, we trained pigeons on a one-to-many matching task with differential sample responding required. Differential outcomes were associated with samples and comparisons, with comparisons only, or with neither samples nor comparisons. Slopes of delay functions for trials with pecked versus nonpecked samples suggested use of a single-code-default strategy in the nondifferential-outcomes group but not in the differential-outcomes groups. In Experiment 2, differential sample responding and differential outcomes were manipulated independently. Again, there were significant differences in the relative slopes of the delay functions. Results suggest that differential outcomes exert their effect independently of differential sample responding.
Address Department of Psychology, University of Kentucky, Lexington 40506
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0097-7403 ISBN Medium
Area Expedition Conference
Notes PMID:7964521 Approved no
Call Number refbase @ user @ Serial 257
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Author Zentall, T.R.; Hogan, D.E.; Edwards, C.A.; Hearst, E.
Title Oddity learning in the pigeon as a function of the number of incorrect alternatives Type Journal Article
Year 1980 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 6 Issue 3 Pages 278-299
Keywords Animals; Choice Behavior; *Color Perception; Columbidae; *Discrimination Learning
Abstract Pigeons' rate of learning a two-color oddity task increased as a function of the number of incorrect alternatives from 2 to 24 in Experiments 1, 2, and 3. In general, pigeons that were transferred from many-incorrect-alternative to two-incorrect-alternative oddity performed better than controls, but considerably below baseline (Experiments 2 and 3). In Experiment 4, pigeons showed no unconditioned tendency to peck the odd stimulus among 24 incorect alternatives, when pecks were nondifferentially reinforced, and in Experiment 5, when this procedure was preceded by oddity training, a progressive drop in odd-stimulus pecking was found. In Experiment 6, pigeons exposed to a nine-stimulus array in which the odd stimulus appeared (a) in the center or (b) separate from the array learned faster than when the odd stimulus was at the edge. This outcome suggests ththe figure-ground relation between the odd stimulus and the incorrect alternatives plays a role in the facilitation produced by increasing the number of incorrect alternatives but that poor performance on the standard, three-alternative oddity task appears to be due to center-odd trials which provide a difficult size or number discrimination.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title (down) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0097-7403 ISBN Medium
Area Expedition Conference
Notes PMID:7391753 Approved no
Call Number refbase @ user @ Serial 268
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