This study attempts to follow the development of an "awareness" of the importance of consistency in a logical system with three elements and one operation. Subjects were 127 male and female students, 9-, 11-, 14-, and 16-years-old. (Author/SDH)

Proposes that humans may have evolved a special sensitivity to certain types of social information during rough-and-tumble play that facilitates social cognition. Describes the cognitive benefits of physical play as providing a break from demanding intellectual tasks and hypothesizes that physical play is related to gender differences in spatial…