Search

Chimpanzees provide help to unrelated individuals in a broad range of situations. The pattern of helping within pairs suggests that contingent reciprocity may have been an important mechanism in the evolution of altruism in chimpanzees. However, correlational analyses of the cumulative pattern of interactions over time do not demonstrate that helping is contingent upon previous acts of altruism, as required by the theory of reciprocal altruism. Experimental studies provide a controlled approach to examine the importance of contingency in helping interactions. In this study, we evaluated whether chimpanzees would be more likely to provide food to a social partner from their home group if their partner had previously provided food for them. The chimpanzees manipulated a barpull apparatus in which actors could deliver rewards either to themselves and their partners or only to themselves. Our findings indicate that the chimpanzees’ responses were not consistently influenced by the behavior of their partners in previous rounds. Only one of the 11 dyads that we tested demonstrated positive reciprocity. We conclude that contingent reciprocity does not spontaneously arise in experimental settings, despite the fact that patterns of behavior in the field indicate that individuals cooperate preferentially with reciprocating partners.

Simple Summary: Lavender (Lavandula angustifolia) used as a therapeutic has been shown to alleviate anxiety and stress in humans but has yet to be studied in nonhuman primates (NHPs). In this study, we administered lavender in the form of oral capsules as a possible therapy to decrease wounding in a subset of chimpanzees, with the thought that decreasing anxiety and stress may also decrease conflict and, therefore, wounding. Overall, wounding did not decrease with lavender therapy; however, the percentage of wounds requiring medical intervention did decrease with lavender therapy. Lavender administration in humans has been shown to promote calmness without the side effects often observed with benzodiazepines. Studies in both humans and rodents have found that ingestion of oral lavender capsules resulted in significantly decreased anxiety. Additionally, mice developed an anti-conflict effect and humans increased socially inclusive behaviors. Given the safety of oral lavender oil and the observed benefits, we administered daily lavender capsules to six chimpanzees who exhibited conflict-instigating behaviors in an effort to further decrease our already low levels of wounding. We compared the total number of wounds in 25 chimpanzees housed with the six lavender-treated chimpanzees in five different social groups (1) prior to administration of daily oral lavender capsules to (2) total wounds during daily oral lavender capsule treatment. We hypothesized that lavender therapy treatment would reduce overall wounding in the social groups. Surprisingly, overall wounding was higher during the lavender treatment period (p = 0.01), yet the percentage of wounds requiring treatment significantly decreased during the lavender therapy period (36% vs. 21%, p = 0.02). [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) infection in humans and animals is concerning. In 2012, our evaluation of a captive chimpanzee colony in Texas revealed MRSA prevalence of 69%. Animal care staff [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2010.02.019 Byline: Sarah F. Brosnan (a)(b)(c), Catherine Talbot (a)(c), Megan Ahlgren (c), Susan P. Lambeth (c), Steven J. Schapiro (c) Abstract: Several species of nonhuman primates respond negatively to inequitable outcomes, a trait shared with humans. Despite previous research, questions regarding the response to inequity remain. In this study, we replicated the methodology from previous studies to address four questions related to inequity. First, we explored the impact of basic social factors. Second, we addressed whether negative responses to inequity require a task, or exist when rewards are given for 'free'. Third, we addressed whether differences in the experimental procedure or the level of effort required to obtain a reward affected responses. Finally, we explored the interaction between 'individual' expectations (based on one's own previous experience) and 'social' expectations (based on the partner's experience). These questions were investigated in 16 socially housed adult chimpanzees using eight conditions that varied across the dimensions of reward, effort and procedure. Subjects did respond to inequity, but only in the context of a task. Differences in procedure and level of effort required did not cause individuals to change their behaviour. Males were more sensitive to social than to individual expectation, while females were more sensitive to individual expectation. Finally, subjects also increased refusals when they received a better reward than their partner, which has not been documented previously. These results indicate that chimpanzees are more sensitive to reward inequity than procedures, and that there is interaction between social and individual expectations that depends upon social factors. Author Affiliation: (a) Department of Psychology, Georgia State University, Atlanta, GA, U.S.A. (b) Neuroscience Institute, Georgia State University, Atlanta, GA, U.S.A. (c) Michale E. Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Bastrop, TX, U.S.A. Article History: Received 4 September 2009; Revised 29 October 2009; Accepted 1 February 2010 Article Note: (miscellaneous) MS. number: A09-00578R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2006.07.016 Byline: Lydia M. Hopper, Antoine Spiteri, Susan P. Lambeth, Steven J. Schapiro, Victoria Horner, Andrew Whiten Abstract: Multiple regional differences in tool use have been identified among wild chimpanzees, Pan troglodytes, but the hypothesis that these represent traditions, transmitted through social learning, is difficult to substantiate without experimentation. To test chimpanzees' capacity to sustain traditions, we seeded alternative tool use techniques in single individuals in different captive groups. One technique, 'Lift', spread in the group into which it was introduced and not in chimpanzees who saw no model or whose group was seeded with the alternative technique, 'Poke'. Poke was also not discovered by control animals tested individually. However, Poke emerged spontaneously in the Lift group and became dominant in both groups, regardless of the founder's Lift or Poke technique. Accordingly, this study demonstrated a statistically significant, differential spread of alternative techniques through social learning, yet no clear separation of traditions, unlike an earlier study with a different population of chimpanzees. This difference may be attributable to prior experience with relevant tools. In further experiments we investigated the basis of the social learning evident in acquisition of the Lift technique, using 'ghost' conditions in which the task was operated automatically rather than by a chimpanzee. Differential movement of the feeding device either by itself or with the tool coupled to it was not sufficient for learning to occur. It appears necessary for a chimpanzee to observe another chimpanzee performing the Lift technique for transmission to ensue. Author Affiliation: (a) Centre for Social Learning and Cognitive Evolution, and Scottish Primate Research Group, School of Psychology, University of St Andrews, U.K. (a ) Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, U.S.A. Article History: Received 7 December 2005; Revised 20 January 2006; Accepted 21 July 2006 Article Note: (miscellaneous) MS. number: 8772R

Positive reinforcement training (PRT) techniques are used for their stress reduction potential in the behavioral management of captive nonhuman primates. The use of PRT can increase effective human-animal communication, help gain the animals' trust by giving them increased control and choice, enhance the animals' well-being, facilitate husbandry practices and improve veterinary and research procedures.

Food-associated calls have received much research attention due to their potential to refer to discovered food in a word-like manner. Studies have found that in many species, food-associated calls attract receivers to the food patch, suggesting these calls play roles in food sharing, cooperation and competition. Additionally, in various species, these calls play a role that has received much less attention: mediating social interactions among foragers that are already nearby or within the food patch, independently of whether they attract outside foragers. In order to increase understanding of the function of the chimpanzee (Pan troglodytes) food-associated rough grunt, we conducted captive playback studies testing whether rough grunt playbacks attract, repel or have no effect on the proximity of foragers already familiarized with the presence of food. We tested how acoustic playbacks of rough grunts (or control calls) from one of two known, identical feeding sites affected receivers' approach and feeding behaviors. More often than expected, participants first approached the feeding site from which rough grunts, but not control calls, were broadcast. However, neither condition increased the likelihood that participants fed first from a given site. Our results support the hypothesis that rough grunts elicit an approach response in receivers, while providing no evidence that they repel. In addition, our study provides evidence that receivers may approach rough grunts even if they do not intend to feed. We discuss the information rough grunts may convey to receivers beyond information about discovered food and the potential benefits signalers may gain from this calling behavior. [ABSTRACT FROM AUTHOR]