Abstract # 4438 Poster # 55:

Scheduled for Thursday, June 20, 2013 07:00 PM-09:00 PM: Session 9 (SG Foyer ABC) Poster Presentation


SERPENTINE SHAPE DETECTION IN COMMON MARMOSETS (CALLITHRIX JACCHUS)

M. G. Rice, S. J. Neal, M. A. Ritzer, J. R. Wombolt and N. G. Caine
Department of Psychology, California State University San Marcos, San Marcos, CA 92096, USA
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     Snakes are among the most important predators of primates. Natural selection has favored neural structures and functions that contribute to snake detection and avoidance. There is some evidence that serpentine shapes rapidly attract the visual attention of human and nonhuman primates under laboratory conditions. We hypothesized that our captive common marmosets would notice serpentine shapes faster and more often than rectilinear and straight shapes during a naturalistic group foraging task. Subjects were seven common marmosets housed outdoors in two family groups. Each marmoset served as a focal animal in five trials for each of the three shape conditions. The speed and frequency with which food placed on serpentine, straight, or rectilinear shaped stimuli were retrieved were the dependent measures. Food on rectilinear shapes was retrieved significantly faster (M=148.7 sec, SD=68.95) than serpentine shapes (M=276.7 sec, SD=114.3), t (5)=2.29, p<.05 and straight shapes (M=333.9 sec, SD=157.2), t(5)=5.26, p<.05. The faster retrieval times in the rectilinear condition may be due to the novelty of that particular shape in the marmosets’ environment. The findings suggest that the marmosets did attend to shape while foraging, but a serpentine shape without additional snake-like characteristics may not be salient enough to warrant the marmosets’ visual attention. We propose that the attentional processes of marmosets were not “fooled” into reacting to the simple serpentine shape as if it needed additional scrutiny.