Foundations Of Cognitive Science


The Wechsler Adult Intelligence Scale (WAIS) (e.g., Wechsler, 1958) was developed by David Wechsler in 1955. This scale has been in constant use since; the most recent revision of the test was published by Pearson in 2008. WAIS measures global or general intelligence and is divided into two parts: the verbal scale and the performance scale. Each of these two parts is further divided into subtests, each of which taps a specific verbal or nonverbal skill. Each subtest has items ranging from easy to increasingly more difficult.

The IQ measure of a person is derived by comparison to a particular reference group, to people of that test subject's age group. Therefore, the raw score has a different meaning depending upon the test subject's age.

The WAIS is not only important to psychologists as a commonly used assessment tool, but it is often at the centre of the debate of whether or not intelligence declines with age. It is questionable whether the current intelligence tests (specifically the WAIS) are appropriate for use with older persons. Belsky (1990) says critics must be looking critically at the appropriateness of the measures themselves, questioning whether existing tests of intelligence are really doing an adequate job of tapping cognitive ability in middle-aged and elderly adults. (p. 119). Belsky further asks if the dramatic age decline is confined mainly to particular subtests. Would we see the same age loss if we looked at data other than the cross-sectional studies used to determine the norms? (p. 121).


  1. Belsky, J.K. (1990). The psychology of aging theory, research, and interventions. Pacific Grove, CA: Brooks/Cole
  2. Wechsler, D. (1958). The measurement and appraisal of adult intelligence (4th ed.). Baltimore,: Williams & Wilkins.

(Revised February 2010)