Hockenbury Discovering Psychology 5th txtbk

296 CHAPTER 7 Thinking, Language, and IntelligenceDavid Wechsler Born in Romania, DavidWechsler (1896–1981) emigrated with hisfamily to New York when he was 6 yearsold. Like Binet, Wechsler believed thatintelligence involved a variety of mentalabilities. He also strongly believed that IQscores could be influenced by personality,motivation, and cultural factors(Matarazzo, 1981).David Wechsler and the Wechsler Intelligence ScalesThe next major advance in intelligence testing came as a result of a young psychologist’sdissatisfaction with the Stanford-Binet and other intelligence tests in widespreaduse. David Wechsler was in charge of testing adults of widely varying culturaland socioeconomic backgrounds and ages at a large hospital in New York City.He designed a new intelligence test, called the Wechsler Adult Intelligence Scale(WAIS), which was first published in 1955.The WAIS had two advantages over the Stanford-Binet. First, the WAIS wasspecifically designed for adults, rather than for children. Second, Wechsler’s test providedscores on 11 subtests measuring different abilities. The subtest scores weregrouped to provide an overall verbal score and performance score. The verbal scorerepresented scores on subtests of vocabulary, comprehension, knowledge of generalinformation, and other verbal tasks. The performance score reflected scores on largelynonverbal subtests, such as identifying the missing part in incomplete pictures, arrangingpictures to tell a story, or arranging blocks to match a given pattern.The design of the WAIS reflected Wechsler’s belief that intelligence involves a varietyof mental abilities. Because the WAIS provided an individualized profile of thesubject’s strengths and weaknesses on specific tasks, it marked a return to the attitudesand goals of Alfred Binet (Fancher, 1996; Sternberg, 1990).The subtest scores on the WAIS also proved to have practical and clinical value. Forexample, a pattern of low scores on some subtests combined with high scores on othersubtests might indicate a specific learning disability (Kaufman, 1990). Or someonewho did well on the performance subtests but poorly on the verbal subtests might beunfamiliar with the culture rather than deficient in these skills (Aiken, 1997). That’sbecause many items included on the verbal subtests draw on cultural knowledge.Wechsler’s test also provided an overall, global IQ score, but he changed the waythat the IQ score was calculated. On the Stanford-Binet and other early tests, theIQ represented the mental age divided by chronological age. But this approachmakes little sense when applied to adult subjects. Although a 12-year-old is typicallyable to answer more questions than an 8-year-old because of developmental differences,such year-by-year age differences lose their meaning in adulthood.Instead, Wechsler calculated the IQ by comparing an individual’s score with thescores of others in the same general age group, such as young adults. The averagescore for a particular age group was statistically fixed at 100. The range of scores isstatistically defined so that two-thirds of all scores fall between 85 and 115—therange considered to indicate “normal” or “average” intelligence. This procedureproved so successful that it was adopted by the administrators of other tests, includingthe current version of the Stanford-Binet. Today, IQ scores continue to becalculated by this method.The Wechsler Intelligence Scale forChildren (WISC) Revised and updated in2003, the WISC-IV is designed to assess theintelligence of children ages 6 to 16. Thispsychologist is administering the WISC-IVblock design subtest to a 6-year-old girl.Other WISC-IV subtests include vocabulary,arithmetic, and arranging pictures so thatthey logically tell a story.