A longitudinal study of hand preference in chimpanzees (Pan troglodytes)

A longitudinal study of hand preferences was assessed in a sample of 53 captive chimpanzees. Four measures of laterality assessed during the first 3 months of life were correlated with three measures of hand preferences assessed when the subjects were between 2 and 5 years of age. In addition, the effect of rearing environment on juvenile hand preferences was assessed in a larger sample of 83 chimpanzees. Overall, some early asymmetries were predictive of juvenile hand preferences, notably head orientation and hand-to-hand activities, and a defensive grasping response. No significant effects of rearing on hand preferences were found but males were more right-handed than females for two of the three juvenile measures. The results are discussed within the context of different developmental models of hand preference in humans.