Study of same-sex play networks found that between ages four and six, the size of girls' play networks decreases along with the number of girls excluded. Although results did not confirm the hypothesis that the size of boys' play networks increases, there was a trend for boys in the older classes to exclude fewer playmates from their networks. (AA)

Written by a methodological behaviorist, this treatise critiques neo-Hullian, Freudian, Eriksonian, and Piagetian theories and presents an ethological perspective on behavior and personality development. The critique is extended to cover social learning, cognitive-developmental, neo-Freudian, and Skinnerian theories, as well as the ideas of…

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…