Specifies some problems in the Piagetian characterizations of assimilation and accommodation and offers an alternative formulation intended to resolve some conceptual anomalies. On the basis of the revision, the orthogenetic law of developmental progression is explicitly derived. Further, Piaget's notion of "equilibrium" is extended into…

Maintains that the "getting into shape" hypothesis of explaining the inverted-U distribution of exercise play across age is likely incorrect. Argues that the biological study of human physical activity play, as recommended by Pellegrini and Smith (1998), will reveal whether physical activity play represents an example of…

Comments on Belsky, Steinberg, and Draper's article in this issue. Discusses the claim for a connection of stressful childhood environments and early pubertal maturation. Argues that early puberty need not imply a shift from a "quality" toward a "quantity" reproductive strategy and that nonevolutionary factors can account for…

Comments on Belsky, Steinberg, and Draper's article in this issue. Offers three likely reasons for adaptation of human behavior. Argues that Belsky, et al. use only two of these reasons in their proposed evolutionary theory of socialization. Suggests that an evolutionary approach is useful if it integrates diverse facts, aids clinical practice,…