Abstract # 13161 Poster # 94:

Scheduled for Thursday, August 9, 2018 06:00 PM-08:00 PM: (Chula Vista ) Poster Presentation


SQUIRREL MONKEYS (SAIMIRI BOLIVIENSIS) RESPOND TO CONTRAST AND INEQUITY IN A GROUP CONTEXT

G. L. Vale1, L. E. Williams1, S. J. Schapiro1, S. P. Lambeth1 and S. F. Brosnan1,2
1Michale E. Keeling Center for Comparative Medicine and Research, The University of Texas MD Anderson Cancer Center, Bastrop, Texas 78602, USA, 2Departments of Psychology, Philosophy, and Neuroscience, and Language Research Center, Georgia State University
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     Like humans, several primate species respond negatively to receiving less preferred rewards than a partner, refusing offered rewards or refusing to participate in the interaction. Previous research involved dyads, so the influence of the social group on these reactions is unknown. Squirrel monkeys are an interesting species to test because they show no inequity response in dyads, but do show a contrast effect, refusing rewards when a preferred one is initially offered. In this group context, monkeys (N=10, females) showed a similar effect, refusing low value (LV) rewards when they were initially shown a high value (HV) or medium value (MV) reward but delivered a LV reward instead, relative to the LV Equity control condition, in which all subjects received LV rewards (Z=-2.366, p=0.018, Z=-2.521, p=0.012 respectively). However, subjects also responded to inequity, refusing LV rewards when others received either a HV or MV reward, compared to in the Equity control (Z= -2.803, p=0.005, Z=-2.366, p=0.018 respectively). No such effect was found for subjects who received MV rewards while the group received HV rewards relative to the MV Equity control (Z=-1.352, p=0.176), or for the MV contrast relative to the MV control (Z=-1.214, p=0.225). Thus, depending upon the rewards involved, squirrel monkeys remain sensitive to contrast and show increased sensitivity to inequity in a social context, although this may be indistinguishable from contrast effects.