Abstract # 2811 Poster # 47:

Scheduled for Thursday, June 17, 2010 07:00 PM-09:00 PM: Session 11 (Medallion Ballroom C/D/E/F) Poster Presentation


RHESUS MONKEYS (MACACA MULATTA) MAY EAVESDROP ON NON-COMMUNICATIVE EXCHANGES

A. F. Hamel, H. E. Gore, L. D. Hardegree and M. A. Novak
University of Massachusetts Amherst, Amherst, MA 01003, USA
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Through eavesdropping, an observer can acquire important information about conspecifics from a safe distance. We have shown that rhesus monkeys can eavesdrop on interactions between experimenters by attending to dominant and submissive facial expressions. However, it is unclear whether the ability to eavesdrop on such communicative signals can be generalized to non-communicative signals. To this end, we presented seven (2 male) surrogate peer-reared monkeys ranging in age from 7 to 24 years, with two different interactions. In the first interaction, a “giver” experimenter handed a treat to a recipient experimenter, and in the second, a “taker” experimenter started to hand a treat to the recipient, but then withdrew it before the other could take hold. Giver and taker roles were randomized across 20 trials. Subjects were video-recorded while viewing the interactions and were allowed to request a treat from either the giver, for which they were rewarded, or the taker, for which they were not. Subjects did not prefer to request a treat from either a giver or a taker [Binomial: P>0.05]. However, analysis of the 120 minutes of video footage showed that subjects did look preferentially at both the giver and the taker in their respective interactions [Paired t-test: P< 0.05]. Since subjects directed their attention to the acting experimenters, it appears that rhesus monkeys may have the ability to eavesdrop on non-communicative signals.