Abstract # 1934 Poster # 88:

Scheduled for Thursday, August 17, 2006 07:00 PM-09:00 PM: Session 8 (Regency West 1/3 ) Poster Presentation


OBJECT PERMANENCE AND SPATIAL MEMORY IN INFANT Macaca Nemestrina: FINDING A HIDDEN OBJECT AFTER A 24-HR DELAY

S. J. Unbehagen, S. E. Ward, D. J. Mandell and G. P. Sackett
University Of Washington,Center on Human Development and Disability and National Primate Research Center, Box 357920, Seattle, WA 98195, USA
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     Human children as young as 14 months successfully search for a hidden object 24 hours after observing the hiding. Object permanence and spatial memory are needed to accomplish this task. We studied search after a 24-hour delay by three infant pigtail groups (G1, <6 months old; G2, 7-12 months; G3, >12 months). Infants were previously trained to open a box to obtain and play with a desirable toy. They were given one minute to play with the toy during the hiding phase. They then saw the toy being hidden in 1 of 4 identical boxes distributed throughout a familiar playroom. After 24 hours, they were given 10 minutes to search for the toy. None of the 9 animals in G1 or the 9 in G3 found the toy with the first box choice, but 4 of 6 G2 animals did (2-tailed p<.01). The toy was eventually obtained by 3 G1, all 6 G2, and 7 G3 monkeys (p=.032), in a median of 3 (G1), 1 (G2), and 4 (G3) choices (Kruskal-Wallis p=.035). Although all monkeys were well beyond the age of attaining object permanence, G1 appeared unable to use this skill, probably due to underdeveloped spatial memory ability. The median latency to correct choice by G3 (283 seconds) was 9 times higher than that of G2 (39.5 seconds), suggesting that their poor performance was due to motivational, rather than, memory factors. Supported by NIH grants RR00166, HD02274.