Abstract # 188:

Scheduled for Friday, June 21, 2013 07:00 PM-09:00 PM: Session 21 (SG Foyer ABC) Poster Presentation


K. Hall1,2,3,4,5, R. W. Byrne3, M. W. Oram3, M. W. Campbell4,5, T. M. Eppley4,5 and F. B. de Waal4,5
1Georgia State University, PO Box 5010, Atlanta, GA 30302-5010, USA, 2MD Anderson Cancer Center, 3University of St Andrews, 4Emory University, 5Yerkes National Primate Research Center
     Recent evidence that chimpanzees (Pan troglodytes) adjust their behavior when they see peers performing better on a food acquisition task contrasts with numerous studies showing chimpanzees’ preference for their original technique, even after observing or discovering a more efficient technique. We tested two pairs of captive chimpanzees (n= 18 and 21 trials) in the informed forager paradigm to address whether chimpanzees, misinformed of the location of a hidden food, would adjust their foraging strategy upon witnessing an informed partner finding food at a different location. One ignorant subject always searched where she had seen the food (false location), whereas a second learned to follow her informed competitor to improve her foraging success (obtaining food on 33% of trials compared to 9.5%). Using cross correlations, we found when ignorant subjects walked towards the false location, they were less likely to follow informed subjects’ gaze than overall (z= -11.34). One ignorant subject adjusted her movement to match the informed subject’s gaze direction (r= 0.08, p<0.05), supporting previous evidence of the use of others’ gaze to modify one’s own tactics. By behaving this way, the ignorant subject improved her foraging success (r= 0.15, p<0.05). The striking variations between individuals indicate that some chimpanzees may have awareness of their own false belief, but others may not.