Abstract # 2895 Poster # 89:

Scheduled for Friday, June 18, 2010 07:00 PM-09:00 PM: Session 18 (Medallion Ballroom C/D/E/F) Poster Presentation


TEMPERAMENT DEVELOPMENT AND SEX DIFFERENCES IN RHESUS MACAQUE INFANTS (MACACA MULATTA) ACROSS DIFFERENT TESTING ENVIRONMENTS

J. C. Songrady, M. F. S. X. Novak, A. M. Ruggiero, E. K. Mallott, N. Bowling, M. L. Miller, E. A. Kerschner, K. Synnestvedt and S. J. Suomi
NIH, NICHD, Laboratory of Comparative Ethology, NIH Animal Center, Poolesville, Maryland 20837, USA
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The development of behavioral reactivity needs to be thoroughly examined. Previous research with infant rhesus macaques found no sex differences between postnatal days 7 and 30 using the Brazelton Neonatal Assessment. Research also suggests no sex differences from 3-7 months using Bayley Scales for infants, but by 8-10 months of age, females were more excitable than males and tended to be more fearful. In free-ranging monkeys, females were more reactive than males by one year of age. In our study, three measures of behavioral reactivity, the occurrence of negative behaviors, refusals to test (balking) and overall reactivity (scale 1–3) were recorded 3-5 times a week during object permanence and Wisconsin General Learning Apparatus (WGTA) learning tasks in nursery-reared monkeys from 2 weeks to 7 months of age [N=20]. Repeated measures ANOVAs [Greenhouse-Geisser corrected F tests, α=0.05] showed the frequency of negative behaviors, the frequency of balking, and general reactivity decreased across time. Generally, females scored higher than males across all three measures; however, this gender effect was not significant [ANOVA, all α=0.05]. These data suggest sex differences, reported in the literature, may not develop until later in the first year. More research is needed, to determine whether the decline in reactivity over time is due to developmental processes or to infants habituating to the testing procedures. Research support by intramural program at NICHD.