Classifying by learning disabled and nondisabled children: Use of overall similarity versus dimensional relations

Abstract

Previous research indicates that learning disabled (LD) children perceive more holistically than do their nondisabled (nonLD) peers. The present study investigated whether or not the holistic perception of LD children is structured by the principle of overall similarity. LD and nonLD children in the second and fourth grades performed a restricted classification task (RCT) with four types of materials. The RCT allows classifications based on overall similarity or dimensional structure. The fourth-grade LD children were more likely than the fourth-grade nonLD children to use overall similarity in making their choices and were less likely than the fourth-grade nonLD children to use the component dimensions of the stimuli. Second-grade LD and nonLD children did not differ. The nonLD children shifted away from similarity choices toward dimensional choices with increasing age, whereas the LD children did not. The results are discussed in terms of their implications for school performance, selective attention, and category generalization.