Piaget, in describing the sequence of classificatory development, describes class inclusion as composed of two processes; hierarchical classification and post-whole comparisons. In the experiment reported here, elementary school children, trained in the concept of sets in first grade mathematics were given a task where they were required to assess…

It was hypothesized that the cognitive structures which underlie performance on class-inclusion tasks also underlie reading comprehension of the stated or inferred main idea of a paragraph, and that performance on three-dimensional class-inclusion tasks developmentally precedes performance on two-dimensional class-inclusion tasks. Ten kindergarten…

Military and civil service carpenters, masons, and plumbers were surveyed using a job inventory checklist and relative time spent rating method along with background item responses. Job clustering and job typing of combined responses were performed and comparisons were made between civilian and military groups as well as comparisons between the…