Wechsler's Contribution to Measures of Intelligence

David Wechsler, a psychologist, believed intelligence involves purposeful action, rational thinking, and effective interaction with the environment.

He developed the Wechsler-Bellevue Intelligence Scale in 1939 by combining subtests that assessed both verbal and nonverbal intelligence.

This test evolved into the Wechsler Adult Intelligence Scale (WAIS), widely used today, with versions for children — Wechsler Intelligence Scale for Children (WISC-V) and Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV).

These tests are recalibrated regularly by administering them to large, diverse groups to ensure accuracy.

The test includes several subtests; for instance, the WISC-V includes 14 subtests across five indices — verbal comprehension, visual-spatial, fluid reasoning, working memory, and processing speed.

Scores from these indices provide a comprehensive view of a person's intelligence, reflecting various cognitive processes.

For example, a child struggling with reading comprehension might score lower on verbal comprehension but excel in fluid reasoning.

The Wechsler scales are reliable and predict outcomes like academic success and career achievements.