Development of intersensory perception in animal and human infants, with a focus on the role of selective attention in perceptual processing, learning, and memory; the influence of prenatal sensory stimulation on behavioral development, particularly the prenatal origins of infant perceptual and social biases and predispositions; the effects of hormones of maternal origin on perceptual and social development. Theoretical efforts address the assumptive base of the nature-nurture debate, the role of experience in development, the origins of phenotypic variation, psychobiological systems theory, the relations between developmental and evolutionary theory, and the history of developmental thinking in biology and psychology.