Baumeister's (1968) hypothesis that mentally retarded children exhibit depressed levels of performance and greater intra-individual variability when compared to intellectually non-handicapped children of similar chronological age was investigated. Eight 10-year-old educable mentally retarded boys and 16 non-handicapped boys, matched by either…

Various counting tasks were presented to 24 congenitally, totally blind children, aged 3-13, to determine the behaviors employed to ensure accurate counting. Three dimensions of tactile strategies were found, including "scanning,""organizing," and "partitioning." A developmental progression in the ontogenesis of each…

This study was designed to examine effects that access to manipulatives in science instruction have with respect to the development of spatial conceptual abilities and whether the effects were different for males and females. A secondary purpose of this investigation was to examine what relationship sex and access to manipulatives in conjunction…

This study explores a learning model which suggests that a concept is acquired first through manipulation of concrete objects followed by transformation of the concrete objects into semi-concrete representations, followed by internalization of the concept through abstract representations. Microcomputer simulations of manipulative activities were…