Abstract # 214:

Scheduled for Friday, June 21, 2013 12:00 PM-12:15 PM: Session 26 (San Geronimo Ballroom B) Oral Presentation


C. F. Talbot1,2,3, A. E. Parrish1,2, H. D. Freeman1,3,4, L. Hopper1,3,4, K. Leverett2, A. N. Holmes3 and L. E. Williams3
1Georgia State University, Department of Psychology, Atlanta, GA 30303, USA, 2Language Research Center, Georgia State University, Atlanta, GA USA, 3Michale E Keeling Center for Comparative Medicine and Research of the University of Texas M. D. Anderson Cancer Center, Department of Veterinary Services, 650 Coolwater Drive, Bastrop, TX 78602, USA, 4Lester E Fisher Center for the Study and Conservation of Apes, Lincoln Par Zoo, Chicago, IL 60614, USA
     Although numerous species respond to contrasts between their current rewards and previous ones, or the outcomes of others, recent evidence suggests that these responses are sensitive to social factors (e.g. sex) and context, such as proximity of the social partner. We tested eight socially housed capuchin monkeys (Cebus apella) and 14 squirrel monkeys (Saimiri boliviensis) using a standard test of inequity in which subjects exchanged tokens to receive food rewards that varied with respect to their partner or their previous offers. In one condition, subjects were separated by a mesh barrier while in the second, there was no barrier, allowing the two participants to be in close proximity. Neither species’ behavior differed across reward conditions when separated (Friedman’s Test; Cebus: n=8, chi2=1.31, d.f.=2, p= 0.519; Saimiri: n=24, chi2=5.4, d.f.=2, p= 0.067). Conversely, when in close proximity, the monkeys’ behavior did change (Friedman’s Test, Cebus: n=8, chi2=9.742, d.f.=2, p=0.008; Saimiri: n=14, chi2=13.736, d.f.=2, p=0.001). Male, but not female squirrel monkeys were sensitive to individual contrast (Sign-Rank Test, males: T+=36, n=8, p=0.012; females: T+=15, n=6, p=0.041), while capuchin monkeys were more sensitive to social contrast, or inequity (Sign-Rank Test, T+=0, n=8, p=0.011). While we cannot parse whether the underlying mechanism is perceptual or social, these results emphasize that context may play an important role in many experimental tests, especially those requiring attention to one’s partner.