ABSTRACT
A critical period is a time period during which an organism is more sensitive and/or vulnerable to certain exogenous stimulus conditions than at other times in its life (Bornstein, this volume; Colombo, 1982). In this chapter, critical periods are discussed and evaluated in the context of mammalian neurobehavioral development, the effects of injuries to the central nervous system, and undernutrition. The problems associated with a strictly defined critical period concept are discussed, and the strict concept is set aside in favor of the more flexible constructs of “optimal” and “sensitive” periods.
