Two strings of letters were presented. Subjects were instructed to indicate whether the second string contained the same elements as the first, regardless of position. Reaction time increased with the number of positions that the letters were displaced. Results indicate that order may be an important factor in retrieval from memory. (Author/BW)

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…

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…