ABSTRACT
Approximately three decades ago, Lee Cronbach deplored the separation then existing between experimental and differential psychologists. Cronbach (1957) wrote that “It is shortsighted to argue for one science to discover the general laws of mind … and for a separate enterprise concerned with individual minds” (p. 673), and he urged a merger of these traditional approaches. In the 1980s several of these mergers exist and one of the most visible is the large number of experimental, cognitive, and developmental psychologists whose research addresses various populations of handicapped individuals.
