Reviews Greenough, Black, and Wallace's (1987) conceptual framework for understanding the effects of early experience and sensitive periods on development, and illustrates the applicability of their model with recent data on the consequences for animals and human infants of the acquistion of self-produced locomotion. (BN)

Recent studies on the biological development of the prefrontal cortex in rhesus monkeys are reviewed. These studies have elucidated the basic neural circuitry underlying the delayed-response function in adult nonhuman primates and suggest that a critical mass of cortical synapses is important for the emergence of this cognitive function. (BN)

The developmental pattern of concurrent synaptogenesis in rhesus monkeys is consistent with a straightforward model of relations between brain and cognitive development. Concurrent synaptogenesis is hypothesized to lay the primary cortical foundation for a series of developmental levels in middle infancy that have been empirically documented in…

Considers the nature and developmental functions of physical activity play. Distinguishes three kinds of physical activity play with consecutive age peaks: rhythmic stereotypies, exercise play, and rough-and-tumble play. Considers gender differences and function in terms of immediate and deferred consequences in physical, cognitive, and social…