Intelligence and Intelligence Testing for AP Psychology

The Wechsler Intelligence Scales

David Wechsler developed another set of age-based intelligence tests: the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) for preschool children, the Wechsler Intelligence Scale for Children (WISC) for ages 6 to 16, and the Wechsler Adult Intelligence Scale (WAIS) for older adolescents and adults. The latest edition, the WAIS-III, has a verbal scale including items on comprehension, vocabulary, information, similarities, arithmetic, and digit span; and a performance scale including items dealing with object assembly, block design, picture completion, picture arrangement, and digit symbols. Wechsler based his measures on deviation IQs or how spread out the scores were from the mean of 100 (Figure 15.1). Since intelligence has a bell curve distribution, 68% of the population will have an IQ between 85 and 115. These test takers are considered to be low normal through high normal. Test takers who fall two deviations below the mean have a score of 70, typically considered the borderline for mental retardation, while test takers two standard deviations above the mean have scores of 130, sometimes considered intellectually gifted, and those three standard deviations above the mean have scores of 145, sometimes considered geniuses. The Wechsler tests are judged more helpful for determining the extremes of intelligence at the mentally retarded and the genius level than the Stanford-Binet. They also help indicate possible learning disabilities when a child's performance IQ is very different from his/her verbal score.

Mental Retardation

Some people prefer the term cognitively disabled rather than mentally retarded. Degrees of mental retardation vary from mild to profound. To be considered mentally retarded, an individual must earn a score at or below 70 on an IQ test, and also show difficulty adapting in everyday life. Typically, mildly retarded individuals (about 85%) score between 50 and 70 on IQ tests, are usually able to care for themselves, can care for a home, achieve a sixth-grade education, hold a job, get married, and become an adequate parent. In schools, they are often mainstreamed, or integrated into regular education classes. Moderately retarded individuals (about 10%) score between 35 and 49 on IQ tests; may achieve a second-grade education; may be given training in skills such as eating, toileting, hygiene, dressing, and grooming so that they can care for themselves; and may be given basic training in home management, consumer, and community mobility skills so that they can hold menial jobs and live successfully in a group home. Severely retarded individuals (about 3–4%), with IQs between 20 and 34, typically develop a very limited vocabulary and learn limited self-care skills. Usually they are unable to care for themselves adequately and do not develop enduring friendships. Profoundly retarded individuals (1–2%), with IQs below 20, require custodial care. Communities have been housing a greater proportion of mentally retarded people than in the past. These people live with their own families or in group homes when possible. This deinstitutionalization is termed normalization.

Kinds of Intelligence

Is there one underlying capacity for intelligence or do we have different, distinct ways of being intelligent? A contemporary of Alfred Binet, Charles Spearman tested a large number of people on a number of different types of mental tasks. He used factor analysis, a statistical procedure that identifies closely related clusters of factors among groups of items by determining which variables have a high degree of correlation. Because all of the mental tasks had a high degree of correlation, he concluded that one important factor, which he called g, underlies all intelligence. Because the correlation wasn't a perfect 1.0 between all pairs of factors, he also concluded the existence of the less important s, or specialized abilities. Louis Thurstone disagreed with Spearman's concept of g. Based on factor analysis of tests of college students, Thurstone identified seven distinct factors he called primary mental abilities, including inductive reasoning, word fluency, perceptual speed, verbal comprehension, spatial visualization, numerical ability, and associative memory. J. P. Guilford divided intelligence into 150 different intelligence sets.

John Horn and Raymond Cattell determined that Spearman's g should be divided into two factors of intelligences: fluid intelligence, those cognitive abilities requiring speed or rapid learning that tend to diminish with adult aging; and crystallized intelligence, learned knowledge and skills such as vocabulary that tend to increase with age.

Multiple Intelligences

Howard Gardner is one of the many critics of the g or single factor intelligence theory. Savants, individuals otherwise considered mentally retarded, have a specific exceptional skill, typically in calculating, music, or art. To Howard Gardner, this is one indication that a single factor g does not underlie all intelligence. He has proposed a theory of multiple intelligences. Three of his intelligences are measured on traditional intelligence tests: logicalmathematical, verbal-linguistic, and spatial. Five of his intelligences are not usually tested for on standardized tests: musical, bodily-kinesthetic, naturalistic, intrapersonal, and interpersonal. According to Gardner, these abilities also represent ways that people process information differently in the world, which has led to changes in how some school systems classify gifted and talented children for special programs. Peter Salovey and John Mayer labeled the ability to perceive, express, understand, and regulate emotions as emotional intelligence.

Salovey's and Mayer's emotional intelligence combines Gardner's intrapersonal and interpersonal intelligences. Salovey, Mayer, and David Caruso developed the Multifactor Emotional Intelligence Scale (MEIS) to measure emotional intelligence. The items test the test taker's ability to perceive, understand, and regulate emotions. Robert Sternberg also believes that intelligence is more than what is typically measured by traditional IQ tests, and has described three distinct types of intelligence in his triarchic theory of intelligence: analytic, creative, and practical. Analytical thinking is what is tested by traditional IQ tests and what we are asked to do in school—compare, contrast, analyze, and figure out cause and effect relationships. Creative intelligence is evidenced by adaptive reactions to novel situations, showing insight, and being able to see more than one way to solve a problem. Practical intelligence is what some people consider "street smarts." This would include the ability to read people, knowing how to put together a bake sale, or being able to get to a distant location. Whether it is labeled as emotional intelligence, interpersonal intelligence, or practical intelligence, such emotionally smart people can often succeed in careers, marriages, and parenting, where people with higher IQ scores, but less emotional intelligence, fail.

Creativity

Creativity, the ability to generate ideas and solutions that are original, novel, and useful, is not usually measured by intelligence tests. According to the threshold theory, a certain level of intelligence is necessary, but not sufficient for creative work. Although many tests of creativity have been developed, such as the Torrance Test of Creative Thinking, the Christensen-Guilford Test, the Remote Associates Test, and the Wallach and Kogan Creative Battery, they do not have high criterion-related validity.

Because tests are used to make decisions, they are criticized for their shortcomings. Although psychometricians, other psychologists, educators, and ethicists agree that intelligence tests measure the ability to take tests well, they do not agree that intelligence tests actually measure intelligence. Since results of intelligence tests correlate highly with academic achievement, they do have predictive validity.

Review questions for this study guide can be found at:

Testing and Individual Differences Review Questions for AP Psychology