Abstract # 99:

Scheduled for Friday, June 22, 2012 12:00 PM-12:15 PM: Session 14 (Magnolia) Oral Presentation


     Prosociality, or the aid one individual provides to another, has been extensively studied in captive chimpanzees. However, little is understood about factors that influence prosociality. In this study, prosocial behavior in captive chimpanzees was examined in two conditions where the focal was provided with either a bag of food (Food) (n=33) or several tools (Tool) (n=47) needed to extract food from a pipefeeder. Twenty-two were tested in both the Food and Tool conditions. If a focal gave or tolerated the item being removed from their possession it was considered ‘sharing’. Communicative signals used to elicit sharing were examined in relation to the positive (PS) or negative (NS) valence of the signal. Individuals were more likely to share in the Tool than the Food condition, z = 2.863, p < 0.003, as well as share with more individuals, t(21) = 5.37, p < 0.001. Furthermore, mother-reared chimpanzees were more likely to share than those raised by humans in a nursery setting for both the Tool X2(1, n=43) = 5.17, p < 0.05 and Food conditions X2(1, N=29) = 5.18, p < 0.04. For the Food but not Tool condition, PS communication signals increased the likelihood of sharing, z = -3.55, p < 0.001. These findings suggest that sharing food occurs more often when positive communicative signals are used. Rearing experiences also appear to influence prosociality.