School psychology, defined as the study and application of psychological principles to the educational setting, encompasses the study of learning and cognition, development, social behavior, individual differences, and measurement and statistics. The purpose of this paper is to provide an historical account of the origins of educational psychology with a focus on its early history and major contributors. Emphasis is placed on the importance of the notion of individual differences, the paradigm which has functioned as a major impetus in the development of intelligence testing. Major contributors discussed are: Francis Galton, Granville Stanley Hall, Arnold Gesell, Lightner Witmer, William James and James McKeen Cattell. It is concluded that the development of the intelligence test was largely a function of the zeitgeist of American society. The lack of innovations made in the assessment of intelligence is seen as a vestige of functionalism in that the currently used instruments meet the minimum needs of the individuals using them--they have great pragmatic value for labeling and placement of individuals into special programs. Contains six references. (JBJ)