APA Dictionary of Psychology

a phenomenon in which people with certain attributes (e.g., personality traits, cognitive styles) respond better to one type of intervention, whereas people with different attributes respond better to another. For example, people with high spatial aptitudes might learn better when material is presented to them visually with charts and diagrams, whereas people with high verbal aptitudes might learn better when the same material is presented in words. The influence of personal characteristics on treatment outcome is of particular interest in educational and psychotherapeutic contexts, given the goal of finding the optimal instructional method or intervention for different types of people. [identified in 1977 by U.S. psychologists Lee J. Cronbach and Richard Eric Snow (1936–1997)]