5 Steps to a 5 AP Psychology, 2010-2011 Edition - Laura Lincoln Maitland [142]
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.
Figure 15.1 The normal curve.
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: logical-mathematical, verbal-linguistic, and spatial. Five of his intelligences are not usually tested for on standardized tests: musical, bodily-kinesthetic, naturalistic,