Nonoperational first graders were taught Piaget's horizontality concept. In comparison to control subjects, training group subjects significantly increased correct responses, maintained their gains, and transferred their training from a straight-sided jar to a round-sided jar. (Author/DB)

This study investigated whether object-picture discrepancy occurs because preschool children regard pictures as significates rather than as signifiers. Results indicated the children did not consistently respond to objects and their pictorial representations equivalently. (Author/DB)

These results support Piaget's position that preoperational children respond to the perceptual lack of equality but not to the lack of conceptual equivalence in class-inclusion problems. (Authors)