Chapter 11 Intelligence
Intelligence • What is intelligence? • Psychologist debate: Should we consider intelligence as one aptitude or many? As neurologically measurable? • Intelligence is a socially constructed concept. • Cultures deem “intelligent” whatever attributes enable success in those cultures. • In each context, intelligence is the ability to learn from experience, solve problems, and use knowledge to adapt to new situations. • Despite this general agreement, two controversies remain? • Is intelligence a single overall ability or several specific abilities? • With the tools neuroscience now offers, can we locate and measure intelligence within the brain?
Reification • Intelligence experts to agree on this: Intelligence is a concept and not a “thing.” • Reification – viewing an abstract, immaterial concept as if it were a concrete thing. • To reify is to invent a concept, give it a material concept, and then convince ourselves that such a thing objectively exists in the world. • When someone says, “She has an IQ of 120,” they are reifying IQ; they are imagining IQ to be a thing one has, rather than a score once obtained on a particular intelligence test. • Correct: “Her score on the intelligence test was 120.”
General Ability or Several Specific Abilities? Charles Spearman (helped develop factor analysis) believed there is also a general intelligence ( g ) factor that underlies the various clusters. He granted that people often have special abilities that stand out, but also noted that those who score high on one factor, typically score higher than average on other factors. This commonality (the g factor) underlies all of our intelligent behavior. Factor analysis – a statistical procedure psychologists use to identify clusters of related items (factors) on a test • Used to identify different dimensions of performance that underlie one’s total score.
7 Primary Mental Abilities • L. L. Thurstone was an opponent of Spearman’s. • He identified seven clusters of primary mental abilities: • word fluency 4. verbal comprehension 6. spatial ability • perceptual speed 5. numerical ability 7. inductive reasoning • memory • Thurstone did not rank his subjects on a single scale of general aptitude. • When other investigators studied the profiles of his subject, they detected a small tendency for those who excelled in one of the 7 clusters to score well on the others. • So, they concluded, there was till some evidence of a g factor.
Multiple Intelligences Howard Gardner – intelligence comes in different packages • Brain damage may diminish one type of ability, not others • Savant Syndrome – low scores on intelligence tests, but an island of brilliance • We have 8 types of intelligences – word smarts, number smarts, music smarts, space smarts, body smarts, self smarts, people smarts, nature smarts • Critics say doesn’t make sense to lump all sorts of abilities under the concept of intelligence. • Intelligence is mental ability • Abilities we can manage without – music/athletics – better considered talents. • Gardner counters that all forms of intelligence have intrinsic value – culture and context place greater value on some. • Indeed, intelligence tends to express people value in a human being
Aspects of successful intelligence Robert Sternberg distinguishes 3 types: • analyticalintelligence (academic problem-solving) • assessed by intelligence tests (well-defined problems w/one answer) • creative intelligence • demonstrated in reacting adaptively to novel situations and generating novel ideas • practical intelligence • often required for everyday tasks, which are frequently ill-defined, with multiple solutions Traditional intelligence tests assess academic intelligence, but do less well in predicting vocational success.
Is Intelligence Neurologically Measurable? Brain Size and Intelligence • 25 modern studies do reveal a slight +.15 correlation between head size (relative to body size) and intelligence scores. • Newer studies that directly measure brain volume using MRI scans reveal a more significant correlation of +.44 between brain size (adjusted for body size) and intelligence score. • As adults age, brain size and nonverbal intelligence scores fall. • Study of Einstein’s brain • Not notably heavier or larger than typical Canadian’s brain. • Was 15% larger in the parietal lobe’s lower region – happens to be the center for processing mathematical and spatial information. • Certain other areas were a tad smaller than average (he was slow in learning to talk).
Emotional Intelligence Social Intelligence Emotional Intelligence (critical part of social intelligence) the ability to perceive, express, understand, and regulate emotions. Emotionally smart people often succeed in careers, marriages, and parenting, where academically smarter (but emotionally less smart) people fail. Critics say this is stretching intelligence too far. the know-how involved in comprehending social situations and managing oneself successfully. • Consistent with this distinction between academic and social intelligence is the repeated finding that college grades only modestly predict later work achievement.
Brain Function and Intelligence • Brain glucose consumption • PET scans done while people with high or low abilities perform cognitive tasks. • High performers’ brains are less active (guzzle less glucose energy) • Verbal intelligence scores are predictable from the speed with which people retrieve information from memory. • Perceptual speed • Across many studies, the correlation between intelligence score and the speed of taking in perceptual information tends to be about +.4. • Those who perceive quickly tend to score somewhat higher on intelligence tests, particularly tests based on perceptual rather than verbal problem solving.
Neurological speed • Do the quicker perceptions of highly intelligent people reflect greater neurological speed? • Repeated studies have found that their brain waves register a simple stimulus (flash of light, beep) more quickly and with greater complexity. • The evoked brain response also tends to be slightly faster when people with high rather than low intelligence scores perform a simple task (pushing a button when an X appears on a screen). • No firm understanding of why fast reactions on simple tasks should predict intelligence test performance. • Perhaps people who more quickly process information accumulate more information.
Alfred Binet: Predicting School Achievement • Began modern intelligence-testing in 1904 when the French government passed a law requiring all children to attend school. • Binet and his collaborator Theodore Simon decided to develop an objective test to identify children likely to have difficulty in regular classes. • All children follow same course of intellectual development but some develop more rapidly. • “Dull” children were merely “retarded” in their development. • On tests, “dull” child should perform as does a typical younger child • “Bright” child should perform as does a typical older child.
Mental Age • Binet and Simon set out to measure what came to be called a child’s “mental age.” • Ex: a 9-year-old should have a mental age of 9. • Theorized that mental aptitude is a general capacity that shows up in various ways. • Developed varied reasoning and problem-solving questions that might predict school achievement. • They succeeded to find items that did predict how well the children handled schoolwork. • They made no assumptions concerning why a particular child was slow, average, or precocious. • Binet leaned toward environment. • Hoped his test would be used to improve children’s education, but he feared it would be used to label children and limit their opportunities.
Lewis Terman: The Innate IQ • Stanford U. professor Terman attempted to use Binet’s test to numerically measure inherited intelligence, but found Paris-developed age norms did not work well with California children. • He revised the test – adapted some of Binet’s original items, added others, established new age norms, and extended the upper end of the test’s range from teenagers to “superior adults.” • Called the revised test the “Stanford-Binet.
William Stern • German psychologist who derived the famous “intelligence quotient” (IQ). • Simply, a person’s mental age divided by chronological age and multiplied by 100 to get rid of the decimal point. • Thus, an average child, whose mental and chronological ages are the same, have an IQ of 100. • An 8-year-old who answers questions as would a typical 10-year-old has an IQ of 125.
Current Intelligence Tests • Most, including the Stanford-Binet, no longer compute an IQ, because it works for children but not adults. • Today’s intelligence tests produce a mental ability score based on the test-taker’s performance relative to the average performance of others the same age. • Current scores also define 100 as average, but there is no longer a “quotient.” However, the word IQ is still used as an expression for “intelligence test score.” • 2/3 of all people fall between 85 and 115.
Terman’s test for Immigrants • Terman promoted intelligence testing to try to stop the “unusually prolific breeding” of certain ethnic groups. • Envisioned use of the tests would “ultimately result in curtailing the reproduction of feeble-mindedness and in the elimination of an enormous amount of crime, pauperism, and industrial inefficiency” (discourage certain people from reproducing). • With Terman’s help, U.S. government developed new tests to evaluate newly arriving immigrants and 1.7 million WWI army recruits (1st mass admin. of tests). • Led to the 1924 immigration law – reduced immigration quotas for Southern & Eastern Europe to less than 1/5 of those from Northern band Western Europe (superiority of Anglo-Saxons). • Terman came to appreciate that test scores reflect not only people’s innate mental abilities but also their education and their familiarity with the culture assumed by the test.
Modern Tests of Mental Abilities • Aptitude tests • Tests intended to predict your ability to learn a new skill. • College entrance tests are aptitude tests. Differences are not so clear-cut. • Achieved vocabulary influences your score on most aptitude tests. • Your aptitudes for learning and test-taking influence your grades on tests for achievement. • Most tests, whether labeled aptitude or achievement, assess both ability and its development. • However, aptitude tests predict future performance and achievement tests assess current performance. • Achievement tests • Tests intended to reflect what you have learned. • Exams covering what you have learned in this course.
WAIS (Wechsler Adult Intelligence Scale) • Today’s most widely used intelligence test. • Developed by psychologist David Wechsler (a 6-year-old immigrant from Easter Europe) labeled feeble-minded. • Later developed a WISC (Weschler Intelligence Scale for Children) and even later a test for preschoolers. • Consists of 11 subtests, it yields an overall intelligence score, but also separate “verbal” and “performance” (nonverbal) scores. • Striking differences can alert the examiner to possible problems. • Also provide clues to cognitive strengths that a teacher or employer might build upon.
Principles of Test Construction Standardization • To evaluate your performance, need a basis for comparing it with others’ performances. • Must first give test to a representative sample of people. • This process of defining meaningful scores relative to a pretested group is called standardization. • Standardized test results typically form a normal distribution (bell-shaped curve). • Tests are periodically re-standardized. • The Flynn Effect – mystery – intelligence test performance has been improving. BUT college aptitude tests are declining.
Reliability • A good test must yield dependably consistent scores. • To test reliability, retest with same test or another form of it (or split in half—see if odd & even agree). • If two scores correlate, the test is reliable. • The higher the correlation between test/retest or split-half test, the higher the test’s reliability. • Stanford-Binet, WAIS, and WISC all have very high reliability, about +.9
Validity • High reliability does not ensure validity – the extent to which the test measures what it is supposed to measure or predicts what it is supposed to predict. • Content validity – the test taps the pertinent behavior (road test for driver’s license or course exams). • Predictive validity – the test predicts future achievement. Are general aptitude tests as predictive as they are reliable? • No – fairly strong in early grades, but weakens later. • Example: Elite colleges / grad school narrow range GRE
The Dynamics of Intelligence Stability or Change? • The search for indicators of infants’ later intelligence has left few stones unturned. • One test revealed that 2- to 7-month-old babies who quickly grow bored with a picture, and given a choice, prefer to look at another, score higher on tests of brain speed and intelligence up to 11 years later. • However, before age 3, test predict only minimally how toddlers will perform later. • By age 3, children’s performances on intelligence tests begin to predict their adolescent and adult scores. (High scoring adolescents tend to have been early readers.) After about age 7, scores stabilize.
Extremes of Intelligence The Low Extreme The High Extreme Gifted Programs (proponents and critics) Most do attain high levels of education “Tracking” is placing students in separate classes with others who share their level of aptitude. Critics say tracking tends to lower students’ self- esteem and sometimes creates a self-fulfilling prophecy. Some research has concluded that the academic achievement scores of tracked students are not higher than those of non-tracked students. Presumes that giftedness is a single trait, rather than just one of many potentials, which reifies giftedness. It ignores the fact that we, not nature, are deciding the criteria for giftedness. Mental retardation • Intelligence scores below 70 • Must meet two criteria: low test score & difficulty with independent living • Males outnumber females by 50% • Down’s Syndrome (varying severity)
Critics and Proponents of G.T. • Both agree on this much: Children have differing gifts. • By packaging different gifts in different bodies, nature enhances a group’s welfare and the odds that some will survive environmental challenges. • Educating children as if all were alike is as naïve as assuming that giftedness is something you either have or don’t have. • It is not necessary to hang value-laden labels on children to challenge them all at the frontiers of their abilities. • By providing “appropriate developmental placement” suited to their talents, we can promote both equity and excellence for all. At age 10, Lenny Ng became the youngest child to score a perfect 800 on the SAT math test. He entered Harvard at age 16, and graduated Summa Cum Laude three years later. At age 20, he was a second-year graduate student in mathematics at MIT.
Creativity and Intelligence • Creativity – the ability to produce ideas that are both novel and valuable (varies by culture). • Results from tests of intelligence and creativity suggest that a certain level of aptitude is necessary but not sufficient for creativity. • There is more to creativity than intelligence tests reveal. • Expertise (well-developed base of knowledge) • Imaginative thinking skills (ability to see things in a new way) • A venturesome personality (tolerates ambiguity and risk) • Intrinsic motivation (the pleasure and challenge of their work) • A creative environment (sparks, supports, and refines creative ideas)
Genetic Influences on Intelligence • Do people who share the same genes also share comparable mental abilities? Yes. • Across five studies, the intelligence test scores of 163 identical twins reared together are virtually as similar as those of the same person taking the same test twice. Fraternal twins are must less similar in their scores. • Even identical twins reared apart have similar scores. • Among the many genes that combine to influence intelligence, one, located on chromosome 6, has recently been identified. In one study, the gene was carried by about 1/3 of children with very high intelligence scores but only 1/6 of those with average scores. • By inserting an extra gene into fertilized mouse eggs, researchers have produced smarter mice (excel at learning and memory).
Adopted children – nature or nurture? • With age, mental similarities between adopted children and their adoptive families disappear as the effect of common rearing wanes. • By adulthood, the correlation is roughly zero. • With age, genetic influences become more apparent. • Adopted children’s intelligence scores become more like their biological parents. • Identical twins’ similarities continue or increase into their eighties.
Environmental Influences on Intelligence • The environment that siblings share doesn’t much influence their aptitudes, but it significantly influences their scholastic achievement. • Severe life experiences do leave marks on us. • Although malnutrition, sensory deprivation, and social isolation can retard normal brain development, the difference between normal and “enriched” environments matters less. • There is no environmental recipe for superbabies. • Extra instruction has little effect on the intellectual development of children from stimulating environments. • However, quality programs for disadvantaged children produce at least short-term cognitive gains, even on intelligence tests.
Schooling Effects • Schooling and intelligence contribute to each other (and enhance later income). • High intelligence is conducive to prolonged schooling. • Also true – intelligence scores tend to rise during the school year and drop over the summer months. • Completing high school elevates intelligence scores over those obtained by comparable children who leave school early. • Children whose birthdays just make the cutoff point for school entrance temporarily have higher intelligence scores than those born just slightly later, who are a year behind them in school.
Ethnic Similarities and Differences in Intelligence Test Scores • Two disturbing but agreed-upon facts: • Racial groups differ in their average scores on intelligence tests. • High-scoring people (and groups) are more likely to attain high levels of education and income. • The Bell curve for Whites is centered roughly around IQ 100; for African Americans roughly around 85, and those for different subgroups of Hispanics roughly midway between. • Has dropped in recent years, but gap still exists. • Such group differences provide little basis for judging individuals - millions of Blacks have higher IQs than the average White. • Differences among other groups as well: • European New Zealanders outscore Maori New Zealanders • Israeli Jews outscore Israeli Arabs • Those who can hear outscore those born deaf.
There is evidence that the racial gap my be environmental: • Genetics research reveals that under the skin, the races are remarkably alike. Individual differences within a race are much greater than differences between races. Europeans and Africans are genetically closer than Africans and Aboriginal Australians. • Asian students outperform North American students on math achievement and aptitude tests. But it’s a recent phenomenon and may reflect conscientiousness rather than competence. In Asia, students spend 30% more days per year in school and spend time out of school studying math. • The intelligence test performance of today’s better-fed and better-educated population exceeds that of the 1930s by the same margin that the intelligence test score of the average White today exceeds that of the average Black (not genetic). • White and black infants have scored equally well on an infant intelligence measure (a predictor of future intelligence scores). • In different eras, different ethnic groups have experienced golden ages – periods of remarkable achievement – cultures rise and fall – genes do not. Makes it difficult to attribute a natural superiority to any race.
How about after high school graduation? • During college, black students’ scores increased more than four times as much as those of their white counterparts, thus greatly decreasing the aptitude gap. • Black and white students complete more grades in high school environments that differ in quality, and the gap in scores widens. • However, at the college level, where both are exposed to educational environments of comparable quality – many blacks are able to close the gap in test scores.
Gender Similarities and Differences • In the psychological domain, gender similarities vastly outnumber gender differences. • There is no gender gap in intelligence scores But people like to concentrate on the differences: • Girls are better spellers, more verbally fluent, and more sensitive to touch, taste, and odor. • Boys tend to talk later and stutter more often. • In remedial reading, boys outnumber girls 3 to 1. • Boys outnumber girls at the low extremes and therefore in special ed. classes. • In high school, underachieving boys outnumber girls by 2 to 1.
Math and Spatial Aptitudes • In math grades, the average girl surpasses the average boy. • On math tests given to 3 million representatively sampled people in 100 independent studies, males and females obtained nearly identical average scores. • BUT people like differences: • Females have an edge in math computation, but males in 20 of 21 countries scored higher in math problem solving. • Male high school seniors average 45 points higher on the 200- to 800-point SAT math test (got 4 more answers right). • Because US National Merit Scholarships are based on SAT scores, only about 35% of these awards have done to girls (despite their generally higher grades).
Score differences are sharpest at the extremes: • In Western countries, nearly all math prodigies participating in the International Mathematics Olympiad have been males (but females in non-Western countries, such as China). • Do natural sex differences explain why most mathematicians and more than 9 in 10 rated chess players, and American architects, engineers, and mapmakers are men? • High levels of male sex hormones during prenatal period does enhance spatial abilities, but social expectations also shape boys’ and girls’ interests and abilities. • As more and more girls are encouraged to develop their abilities in math and science, the gender gap is narrowing.
The Question of Bias Are intelligence tests biased? Depends on two different definitions of bias: • the tests detect not only innate differences in intelligence but also differences caused by cultural experiences. • In this case, yes, they are biased BUT are the tests responsible? • If unequal past experiences predict unequal future achievements, a valid aptitude test will detect such inequalities. 2) whether a test is less valid for some groups than for others. • Major consensus is that the major aptitude tests are not biased in the statistical meaning of the term. • The predictive validity of the SAT or of a standard intelligence test is roughly the same for Blacks and Whites and for rich and poor.
To predict school performance accurately, an aptitude test must mirror any gender or racial bias in school teaching and testing. • Men outperformed women on a difficult math test (study) UNLESS they had been led to believe that women score as well as men on the test. • Also observed the same self-fulfilling effect on black students’ verbal scores when they took the test under conditions that make them feel threatened. • Conclusion: If you tell students they probably won’t succeed, this stereotype will eventually erode their performance. Over time, they will dis-identify with school achievement.
Threefold Aim First: • We should realize the benefits that Alfred Binet foresaw for intelligence tests – to enable schools to recognize who might best benefit from early intervention. Second: • Remain alert to Binet’s fear that test scores may be misinterpreted as literal measures of a person’s worth and fixed potential. Third: • Remember that intelligence test scores reflect only one aspect of personal competence. • Our practical and emotional intelligence matter, too, as do other forms of talent and character. • The competence that intelligence tests sample is important but far from all-inclusive. • There are many ways of being successful – our personal and cultural differences (regardless of their origins) are variations on the human theme of adaptability.