The Wechsler Adult Intelligence Scale (WAIS)was developed by Wechsler in 1955. An updated version of the scale (WAIS-R) was developed in 1981. WAIS measures global or general intelligence and is commonly used by psychologists. It is divided into 2 parts: the verbal scale and the performance scale. Each of these 2 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.

Verbal subtests measure "our store of knowldedge." (Belsky, 1990, p. 120) They focus on "learned or absorbed knowledge" testing "knowledge of historical, literary or biological facts; knowledge relating to competent functioning in the world; knowledge of mathematics; knowledge of the meaning of specific words." (Belsky, 1990, p. 120)

Performance subtests (except picture completion) contain relatively unfamiliar tasks. They measure "on-the-spot analytical skills, how well a person can master a new, never before encountered problem." (Belsky, 1990, p. 120) Speed is critical to these tasks as these subtests are timed.

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 asks further 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)

Belsky, Janet K. (1990). The Psychology of Aging Theory, Research, and Interventions. Pacific Grove: Brooks/Cole Publishing Company.

See Also:

Crystallized Intelligence/ Fluid Intelligence

Contributed by Cassie Jacknicke, November 24, 1995