A significant positive correlation between multiple classification was found, in testing 65 children aged 6 to 8 years, at the stage of concrete operations. This is interpreted as support for the existence of a structure d'ensemble of operational schemes in the period of concrete operations. (Authors)

Demonstrated is a covariance principle that causes the observer to assume that if one aspect of a two-dimensional figure (its perimeter or its area) is conserved, the other aspect must also be conserved (pseudo-conservation). Mentally retarded individuals, assuming no such fixed relationship, correctly judged the changed state of the nonconserved…

A study was designed to develop an instrument and methodological procedure to assess transitive relations within seriation problems in elementary school children using three criteria: explanations, judgments, and strategies. A secondary analysis to assess transitivity used the three criteria according to whether the children were conservers, in…

Performance data for 42 subjects pertaining to seven course objectives and ten propositional logic tasks were analyzed for hierarchical relationships using ordering theoretic technique. The resulting hierarchy indicated that simple implication and particular contraposition propositional logic tasks were prerequisite to some course objectives. This…

This research attempts to diagnose the skills required for successful spatial performance in order to provide a theoretical foundation for military training in such tasks as map reading, surveying, and navigation. It is known that successful performance on spatial tasks depends on task requirements (e.g., requisite knowledge, alternative paths to…