David Wechsler, a Jewish American psychologist best known for his contributions to intelligence theory and intellectual assessment, was born in Lespedi, Romania, January 12, 1896. When he was 6, his family moved to New York City. Wechsler earned a bachelor’s degree from City College of New York in 1916, a master’s degree from Columbia University in 1917, and a doctor of philosophy from Columbia University in 1925, the latter degrees earned under Robert S. Woodworth.
After gaining military experience in assessment during World War I, partly under Edwin G. Boring, Wechsler was transferred to the University of London in 1919. There he studied with Charles E. Spearman and Karl Pearson. Both Spearman and Pearson were interested in the nature and measurement of intelligence, and Spearman had already introduced his two-factor intelligence theory. In 1920, Wechsler was awarded a 2-year fellowship to study psychogalvanic response (the topic of his future dissertation) at the University of Paris under Louis Lapique and Henri Pieron.
After receiving his Ph.D., Wechsler accepted an offer from James McKeen Cattell to serve as acting secretary for The Psychological Corporation. He resigned in 1927 to open a clinical practice, and in 1932 he was appointed as Chief Psychologist at Bellevue Psychiatric Hospital. The following year he was appointed as clinical professor to the Medical College at New York University, and he remained at both positions until 1967.
Based in part on his extensive clinical experience, Wechsler found current theories of intellectual assessment to be too simplistic, and he considered the available assessments to be too limited. Ultimately, Wechsler came to view intelligence as the global capacity to act purposefully, think rationally, and deal effectively with one’s environment. That view guided his work in developing batteries for assessing the intelligence of adults and children.
Wechsler’s adult intelligence battery was published in 1939 as the Wechsler-Bellevue Intelligence Scale and revised in 1942 as the Wechsler-Bellevue II (“Army Wechsler”). It was renamed the Wechsler Adult Intelligence Scale (WAIS) in the 1955, 1981, and 1997 (WAIS-III) revisions. The Wechsler Intelligence Scale for Children was published in 1949 (WISC), and revised in 1974 (WISC-R), 1991 (WISC-III), and 2003 (WISC-IV). For younger children, Wechsler developed the Wechsler Preschool and Primary Scale of Intelligence in 1967 (WPPSI; currently WPPSI-III). Wechsler developed other instruments, such as the Wechsler Memory Scale (WMS) in 1945 (currently WMS-III). Wechsler realized the limitations of psychological tests and believed his scales should be used in coordination with other assessment techniques.
An important theoretical contribution was Wechsler’s introduction of the Deviation Quotient. Up to that time an Intelligence Quotient (IQ) was obtained by calculating a “mental age” score based on the performance of a representative sample of the American population. The “mental age” score was then divided by the examinee’s chronological age to obtain an (IQ). However, a substantial decline in cognitive processing speed occurs as a function of age. This rendered earlier IQ scores less and less useful as the individual ages. Wechsler solved this problem by developing separate norms for a variety of age groups and comparing the examinee’s performance with that of individuals of similar age. Wechsler’s Deviation Quotient has been universally adopted as providing the most meaningful representation of adult intelligence.
Wechsler died May 2, 1981, in New York City.
References:
- Matarazzo, J. D. (1981). David Wechsler (1896-1981). American Psychologist, 36(12), 1542-1543.
- Wechsler, D. (1944). The measurement of adult intelligence (3rd ed.). Baltimore: Williams & Wilkins.
- Wechsler, D. (1974). Selected papers of David Wechsler. New York: Academic Press.
See also:
- History of Counseling
- Counseling Psychology