Abstract # 55:

Scheduled for Thursday, August 17, 2006 05:00 PM-05:15 PM: Session 6 (Regency East #3) Oral Presentation


INTERACTIONS BETWEEN REWARD EXPECTATION AND SWEEPING ACROSS A LINEAR ARRAY OF DOTS IN AN AUTOMATED TOUCHSCREEN DRAWING TASK BY A CAPTIVE CAPUCHIN MONKEY (Cebus apella)

T. Jeyaraj1, I. Iversen3, K. A. Leighty2 and D. Fragaszy1
1University of Georgia, Neuroscience & Behavior Program, Department of Psychology, Athens, GA 30602, USA, 2Disney Animal Kingdom, 3University of North Florida
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     An adult male capuchin monkey learned to sweep his hand through a linear array of dots on a touchscreen, in replication of Iversen and Matsuzawa's (1996) study of drawing in chimpanzees. We report on the monkey's progress focusing on how his reward anticipation (looking towards the feeder) interacted with sweeping. The monkey had to sweep his hand across the array and lift it; after a correct sweep he received a sugar pellet. There were four types of arrays: horizontal, vertical, diagonals left-to-right, and diagonals right-to-left. He participated in 2-4 sessions a day (24 trials a session) for 3 months. We hypothesized that “look-aways” and error frequency would be positively related. We analyzed 17 sessions in which perfect single-stroke sweeps occurred on at least 50% of the trials. We calculated the number of incorrect trials and ‘look-aways’ for each array type. The probability of an error in sweeping significantly depended on the direction of the array (X2(3)=11.99, p<0.01) with most errors for the horizontal array. Counter to the hypothesis, looking away was least likely on arrays in which most errors were committed (X2(3)=26.25, p<0.001). Looking away was more likely after an error in sweeping for arrays in which the subject would normally sweep correctly. We conclude that looking towards the pellet feeder occurred on error trials in which the subject’s sweeping closely resembled sweeping on reinforced trials.