In a study, few subjects accepted empirical evidence of nonconservation of discontinuous quantity and weight. These findings were interpreted as support for the organismic-developmental claim that lower forms of reasoning are transformed into structurally more advanced forms. (Author/ED)

Three experiments using university students explored what constitutes an event and what determines its boundaries. Results supported the hypothesis that sequences of stimuli repeating in different contexts are cut out to become cognitive entities ("things" with a beginning and an end) in their own right. Results suggest that the…

Reports a study of 913 Israeli students in grades 7-12 from randomly chosen heterogeneous homeroom classes to investigate students' Piagetian cognitive levels using a video-based test. Results indicate that less than 50 percent of high school students have mastered formal operational reasoning. (MDH)

This study investigated: (1) whether boys and girls master formal reasoning tasks to the same degree at the same age; (2) if the variance of boys' and girls' performance in formal tasks could be predicted by the same cognitive learning abilities; and (3) what are the main and interactional effects of age, sex, and school type on the variance of…