Intelligence-related differences in semantic processing speed

Abstract

Educable mentally retarded and nonretarded adolescents verified superordinate and basic level descriptions of common objects. Obtained category decision times, as measured by superordinate-basic level difference scores, were longer for retarded than for nonretarded subjects, indicating fundamental group differences in semantic processing speed. Additional data were interpreted as indicating that retarded adolescents may be slower in making basic level as well as superordinate level decisions, suggesting that they have difficulty in making semantic classification decisions in general. Other results, from a semantic priming task performed by the same subjects, suggested that the obtained group differences in semantic processing speed were related to the active (deliberate) processes required for verification, rather than to category knowledge per se or more passive processes associated with the activation of stored semantic knowledge.