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Author Newton-Fisher, N.E.; Lee, P.C. url  doi
openurl 
  Title Grooming reciprocity in wild male chimpanzees Type Journal Article
  Year 2011 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 81 Issue (up) 2 Pages 439-446  
  Keywords altruism; biological market theory; Budongo; chimpanzee; grooming; Pan troglodytes  
  Abstract Understanding cooperation between unrelated individuals remains a central problem in animal behaviour; evolutionary mechanisms are debated, and the importance of reciprocity has been questioned. Biological market theory makes specific predictions about the occurrence of reciprocity in social groups; applied to the social grooming of mammals, it predicts reciprocity in the absence of other benefits for which grooming can be exchanged. Considerable effort has been made to test this grooming trade model in nonhuman primates; such studies show mixed results, but may be confounded by kin effects. We examined patterns of reciprocity within and across bouts, and tested predictions of the grooming trade model, among wild male chimpanzees, Pan troglodytes: a system with negligible kin effects. In accord with the model's expectations, we found that some grooming was directed by lower- to higher-ranked individuals, and that, on average, higher-ranked individuals groomed more reciprocally. We found no support, however, for a prediction that more reciprocity should occur between individuals close in rank. For most dyads, reciprocity of effort occurred through unbalanced participation in grooming bouts, but reciprocity varied considerably between dyads and only a small proportion showed strongly reciprocal grooming. Despite this, each male had at least one reciprocal grooming relationship. In bouts where both individuals groomed, effort was matched through mutual grooming, not alternating roles. Our results provide mixed support for the current grooming trade, biological market model, and suggest that it needs to incorporate risks of currency inflation and cheating for species where reciprocity can be achieved through repeated dyadic interactions.  
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  ISSN 0003-3472 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5329  
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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 (up) 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  
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  Language English Summary Language Original Title  
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  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 Baker, K.C.; Seres, E.; Aureli, F.; De Waal, F.B. doi  openurl
  Title Injury risks among chimpanzees in three housing conditions Type Journal Article
  Year 2000 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 51 Issue (up) 3 Pages 161-175  
  Keywords Aggression; *Animal Welfare; Animals; Female; *Housing, Animal; Male; *Pan troglodytes; Risk Assessment; Wounds and Injuries/*veterinary  
  Abstract Meeting the psychological needs of chimpanzees (Pan troglodytes) can be a challenge given their aggressiveness on the one hand and the complexity of their social lives on the other. It is unclear how to balance the need to provide opportunities for species-appropriate behavior against potential risks of injury chimpanzees may inflict on each other. This study evaluates the suggestion that simpler social environments protect chimpanzees from wounding. Over a two-year period all visible injuries to 46 adult males, 64 adult females, and 25 immature chimpanzees were recorded at the Yerkes Regional Primate Research Center. Approximately half of the subjects were mother-reared, and the rest were nursery-reared. Housing included compounds containing about 20 chimpanzees, interconnected indoor-outdoor runs for groups of up to 12 individuals, and smaller indoor-outdoor runs for pairs and trios. Annual wounding rates were calculated for serious wounds (extensive injuries and all those requiring veterinary intervention) as well as for minor wounds. Compound-housed chimpanzees incurred the highest level of minor wounding, but serious wounding levels were not affected by housing condition. Even with a period of dominance instability and elevated levels of wounding in one compound, compound chimpanzees were not injured more than those in smaller social groups over the long term. Nursery-reared females in moderate-sized groups were wounded more than mother-reared females. Also, nursery-reared males and females were wounded less often when paired with mother-reared companions. Overall, this study indicates that maintaining chimpanzees in pairs and trios would not be an effective means for reducing injuries. The management of wounding in chimpanzee colonies is influenced more by the sex and rearing composition of a colony.  
  Address Living Links Center, Yerkes Regional Primate Research Center, Emory University, Atlanta, Georgia 30322, USA. kateb@rmy.emory.edu  
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  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
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  Notes PMID:10902665 Approved no  
  Call Number refbase @ user @ Serial 188  
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Author Aureli, F.; de Waal, F.B. doi  openurl
  Title Inhibition of social behavior in chimpanzees under high-density conditions Type Journal Article
  Year 1997 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 41 Issue (up) 3 Pages 213-228  
  Keywords Aggression/*psychology; Animals; *Behavior, Animal; *Crowding; Female; Male; Pan troglodytes/*psychology; Population Density; *Social Environment; Stress, Psychological  
  Abstract This is the first study to investigate the short-term effects of high population density on captive chimpanzees (Pan troglodytes). Subjects of the study were 45 chimpanzees living in five different groups at the Yerkes Regional Primate Research Center. The groups were observed under two conditions: 1) when they had access to both the indoor and outdoor sections of their enclosures; 2) during cold days when they were locked into the indoor runs, which reduced the available space by more than half. Under the high-density condition, allogrooming and submissive greetings decreased, but juvenile play increased. Remarkably, the rate of various forms of agonistic behavior, such as aggression, bluff charge, bluff display, and hooting, occurred less frequently under the high-density condition. This general decrease in adult social activity, including agonistic behavior, can be interpreted as an inhibition strategy to reduce opportunities for conflict when interindividual distances are reduced. This strategy is probably effective only in the short run, however. Behavioral indicators of anxiety, such as rough scratching and yawning, showed elevated rates, suggesting increased social tension under the high-density condition.  
  Address Yerkes Regional Primate Research Center, Emory University, Atlanta, GA 30322, USA  
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  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9057966 Approved no  
  Call Number refbase @ user @ Serial 203  
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Author de Waal, F.B. openurl 
  Title Bonobo sex and society Type Journal Article
  Year 1995 Publication Scientific American Abbreviated Journal Sci Am  
  Volume 272 Issue (up) 3 Pages 82-88  
  Keywords Animals; Evolution; Female; Hominidae; Humans; Male; Pan troglodytes/*physiology; Sexual Behavior, Animal/*physiology; Social Behavior  
  Abstract  
  Address Yerkes Regional Primate Research Center, Atlanta  
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  ISSN 0036-8733 ISBN Medium  
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  Notes PMID:7871411 Approved no  
  Call Number refbase @ user @ Serial 206  
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Author Horner, V.; Whiten, A. doi  openurl
  Title Causal knowledge and imitation/emulation switching in chimpanzees (Pan troglodytes) and children (Homo sapiens) Type Journal Article
  Year 2005 Publication Animal cognition Abbreviated Journal Anim. Cogn.  
  Volume 8 Issue (up) 3 Pages 164-181  
  Keywords Animals; Child Behavior; Child, Preschool; *Concept Formation; Female; Humans; *Imitative Behavior; *Learning; Male; Pan troglodytes; *Problem Solving; Psychomotor Performance; *Social Environment; Species Specificity  
  Abstract This study explored whether the tendency of chimpanzees and children to use emulation or imitation to solve a tool-using task was a response to the availability of causal information. Young wild-born chimpanzees from an African sanctuary and 3- to 4-year-old children observed a human demonstrator use a tool to retrieve a reward from a puzzle-box. The demonstration involved both causally relevant and irrelevant actions, and the box was presented in each of two conditions: opaque and clear. In the opaque condition, causal information about the effect of the tool inside the box was not available, and hence it was impossible to differentiate between the relevant and irrelevant parts of the demonstration. However, in the clear condition causal information was available, and subjects could potentially determine which actions were necessary. When chimpanzees were presented with the opaque box, they reproduced both the relevant and irrelevant actions, thus imitating the overall structure of the task. When the box was presented in the clear condition they instead ignored the irrelevant actions in favour of a more efficient, emulative technique. These results suggest that emulation is the favoured strategy of chimpanzees when sufficient causal information is available. However, if such information is not available, chimpanzees are prone to employ a more comprehensive copy of an observed action. In contrast to the chimpanzees, children employed imitation to solve the task in both conditions, at the expense of efficiency. We suggest that the difference in performance of chimpanzees and children may be due to a greater susceptibility of children to cultural conventions, perhaps combined with a differential focus on the results, actions and goals of the demonstrator.  
  Address Centre for Social Learning and Cognitive Evolution, School of Psychology, University of St Andrews, St Andrews, KY16 9JU, UK. vkh1@st-andrews.ac.uk  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15549502 Approved no  
  Call Number refbase @ user @ Serial 732  
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Author Horowitz, A.C. doi  openurl
  Title Do humans ape? Or do apes human? Imitation and intention in humans (Homo sapiens) and other animals Type Journal Article
  Year 2003 Publication Journal of comparative psychology Abbreviated Journal J Comp Psychol  
  Volume 117 Issue (up) 3 Pages 325-336  
  Keywords Adolescent; Adult; Animals; *Appetitive Behavior; Attention; Child, Preschool; Concept Formation; Female; Humans; *Imitative Behavior; Male; Motivation; Pan troglodytes/*psychology; *Problem Solving; *Psychomotor Performance; Reaction Time; Species Specificity  
  Abstract A. Whiten, D. M. Custance, J.-C. Gomez, P. Teixidor, and K. A. Bard (1996) tested chimpanzees' (Pan troglodytes) and human children's (Homo sapiens) skills at imitation with a 2-action test on an “artificial fruit.” Chimpanzees imitated to a restricted degree; children were more thoroughly imitative. Such results prompted some to assert that the difference in imitation indicates a difference in the subjects' understanding of the intentions of the demonstrator (M. Tomasello, 1996). In this experiment, 37 adult human subjects were tested with the artificial fruit. Far from being perfect imitators, the adults were less imitative than the children. These results cast doubt on the inference from imitative performance to an ability to understand others' intentions. The results also demonstrate how any test of imitation requires a control group and attention to the level of behavioral analysis.  
  Address Department of Cognitive Science, University of California, San Diego, CA, USA. ahorowitz@crl.ucsd.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. : 1983 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:14498809 Approved yes  
  Call Number refbase @ user @ Serial 736  
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Author Whiten, A. openurl 
  Title Imitation of the sequential structure of actions by chimpanzees (Pan troglodytes) Type Journal Article
  Year 1998 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 112 Issue (up) 3 Pages 270-281  
  Keywords Animals; Appetitive Behavior/physiology; *Ceremonial Behavior; Exploratory Behavior/physiology; Female; Fruit; Imitative Behavior/*physiology; Learning/*physiology; Male; Pan troglodytes/*psychology; Practice (Psychology); Problem Solving/*physiology  
  Abstract Imitation was studied experimentally by allowing chimpanzees (Pan troglodytes) to observe alternative patterns of actions for opening a specially designed “artificial fruit.” Like problematic foods primates deal with naturally, with the test fruit several defenses had to be removed to gain access to an edible core, but the sequential order and method of defense removal could be systematically varied. Each subject repeatedly observed 1 of 2 alternative techniques for removing each defense and 1 of 2 alternative sequential patterns of defense removal. Imitation of sequential organization emerged after repeated cycles of demonstration and attempts at opening the fruit. Imitation in chimpanzees may thus have some power to produce cultural convergence, counter to the supposition that individual learning processes corrupt copied actions. Imitation of sequential organization was accompanied by imitation of some aspects of the techniques that made up the sequence.  
  Address Scottish Primate Research Group, School of Psychology, University of St. Andrews, Fife, Scotland. a.whiten@st-andrews.ac.uk  
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  ISSN 0735-7036 ISBN Medium  
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  Notes PMID:9770315 Approved no  
  Call Number refbase @ user @ Serial 743  
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Author Dunbar, R.I.M.; McAdam, M.R.; O'connell, S. doi  openurl
  Title Mental rehearsal in great apes (Pan troglodytes and Pongo pygmaeus) and children Type Journal Article
  Year 2005 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 69 Issue (up) 3 Pages 323-330  
  Keywords Algorithms; Animals; Child; Child, Preschool; Food; Frontal Lobe/anatomy & histology/physiology; Humans; *Imagination; Pan troglodytes; Pongo pygmaeus; Problem Solving/*physiology; Psychomotor Performance/physiology; Reward  
  Abstract The ability to rehearse possible future courses of action in the mind is an important feature of advanced social cognition in humans, and the “social brain” hypothesis implies that it might also be a feature of primate social cognition. We tested two chimpanzees, six orangutans and 63 children aged 3-7 years on a set of four puzzle boxes, half of which were presented with an opportunity to observe the box before being allowed to open it (“prior view”), the others being given without an opportunity to examine the boxes before handling them (“no prior view”). When learning effects are partialled out, puzzle boxes in the “prior view” condition were opened significantly faster than boxes given in the “no prior view” condition by the children, but not by either of the great apes. The three species differ significantly in the speed with which they opened boxes in the “no prior view” condition. The three species' performance on this task was a function of relative frontal lobe volume, suggesting that it may be possible to identify quantitative neuropsychological differences between species.  
  Address Evolutionary Psychology Research Group, School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK. rimd@liv.ac.uk  
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  ISSN 0376-6357 ISBN Medium  
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  Notes PMID:15896530 Approved no  
  Call Number Serial 2097  
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Author Mulcahy, N.J.; Call, J. doi  openurl
  Title How great apes perform on a modified trap-tube task Type Journal Article
  Year 2006 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 9 Issue (up) 3 Pages 193-199  
  Keywords Animals; *Discrimination Learning; Female; Gorilla gorilla; Hominidae/*psychology; *Intelligence; Male; *Motor Skills; Pan paniscus; Pan troglodytes; Pongo pygmaeus; *Problem Solving; Species Specificity  
  Abstract To date, neither primates nor birds have shown clear evidence of causal knowledge when attempting to solve the trap tube task. One factor that may have contributed to mask the knowledge that subjects may have about the task is that subjects were only allowed to push the reward away from them, which is a particularly difficult action for primates in certain problem solving situations. We presented five orangutans (Pongo pygmaeus), two chimpanzees (Pan troglodytes), two bonobos (Pan paniscus), and one gorilla (Gorilla gorilla) with a modified trap tube that allowed subjects to push or rake the reward with the tool. In two additional follow-up tests, we inverted the tube 180 degrees rendering the trap nonfunctional and also presented subjects with the original task in which they were required to push the reward out of the tube. Results showed that all but one of the subjects preferred to rake the reward. Two orangutans and one chimpanzee (all of whom preferred to rake the reward), consistently avoided the trap only when it was functional but failed the original task. These findings suggest that some great apes may have some causal knowledge about the trap-tube task. Their success, however, depended on whether they were allowed to choose certain tool-using actions.  
  Address Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany. mulcahy@eva.mpg.de  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16612632 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2469  
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