Abstract # 88:

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


E. L. Nelson1, M. S. Emery2, S. M. Babcock2, S. J. Suomi3, J. Songrady3, A. M. Ruggiero3, M. Miller3, M. F. Novak3 and M. A. Novak1,2
1University of Massachusetts, Neuroscience and Behavior Program, Amherst, MA 01003, USA, 2Department of Psychology, University of Massachusetts, Amherst, MA, 01003, USA, 3Laboratory of Comparative Ethology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Poolesville, MD, 20837, USA

In human and chimpanzee infants, neonatal rightward supine head orientation corresponds to later right hand use. One proposed mechanism for the link between these lateralized behaviors is asymmetric visual experience of the right hand while supine prior to the onset of reaching and manipulating objects. We tested this hypothesis in nursery-reared rhesus macaques [N=16], a species that does not spend time in a supine posture. To test head orientation preference, monkeys were placed supine in an experimenter’s lap and gently restrained with one hand placed on the chest. The monkey’s head was held in a fixed position (midline, left or right) for 15 seconds. The head was then released and the infant’s subsequent head movements were followed via videotape for 30 seconds. Monkeys were given 4 trials per session on days 1, 3, 7, 14, 21, and 30. Hand preference was measured from reaching to objects placed at the infant’s midline. Infants were given 3-5 trials per session, and tested 3 times per week from 14 days to 44 days of age. A population-level left bias was found for supine head orientation [t(15)=-3.272, P<0.01]. Although individual infants had hand preferences, no bias was found at the group-level. Supine head orientation did not predict hand preference in monkeys, suggesting that a mechanism for laterality in monkeys may be different from that of humans and chimpanzees.