Five items requiring use of proportional, probabilistic, and correlational reasoning were administered to students (N=391) in grades 6, 8, 10, and 12. Argues that successful qualitative reasoning arises as a consequence of equilibration and influences selection of course work and that specific instruction may initiate the equilibration process.…

Explores the generality of findings relating intelligence to Inspection Time (IT), the exposure necessary to judge which of two lines is longer, in two studies using normal children and mentally retarded adults. Results showed the relationship between IT and performance IQ was lower in the mentally retarded group. (JAC)

This study used the "double easy-to-hard" paradigm to examine the hypothesis that the class inclusion (CI) task should be equivalent in relational complexity to the transitive inference (TI) problem. Participating in the study were 64 girls and 50 boys, with a mean age of 8 years, 6 months. Stimuli for easy versions of the tasks were…

Discusses several common misunderstandings regarding theories of competence, especially that of psychological reality of competence formalisms. Argues that the claim of the psychological reality of a mechanism,'' as opposed to a structural description, is only appropriate when the mechanism accounts parsimoniously for the widest possible range of…

Attempts to determine the age at which the concept of middleness," or intermediately positioned object, emerges and is functional. (MB)