Intelligence

1. Chapter 10 Intelligence PSYCHOLOGY David G. Myers C. Nathan DeWall Twelfth Edition

2. Chapter Overview • What Is Intelligence? • Assessing Intelligence • The Dynamics of Intelligence • Genetics and Environmental Influences on Intelligence

3. What Is Intelligence? (part 1) • Intelligence: The ability to learn from experience, solve problems, and use knowledge to adapt to new situations. • Spearman’s general intelligence (g) • Humans have one general intelligence that is at the heart of everything a person does. • Mental abilities are like physical abilities. • Intelligence involves distinct abilities, which correlate enough to define a small general intelligence factor. • Gardner and Sternberg discount this theory and propose several different kinds of intelligence.

4. What Is Intelligence? (part 2) • Thurstone’s response • Fifty-six different tests mathematically identified seven clusters of primary mental abilities. • Scoring well on one cluster was generally matched by high scores on other clusters, providing some evidence of g. • Distinct brain networks enable distinct abilities, with g explained by their coordinated activity(Cole et al., 2015; Hampshire et al., 2012). • A chorus of actions are orchestrated through the best possible distribution of mental resources (Carroll & Bright, 2016; Lee et al., 2015).

5. Theories of Multiple Intelligences (part 1) • Gardner’s multiple intelligences • Intelligence consists of multiple abilities that come in different packages. • Eight relatively independent intelligences exist, including the verbal and mathematical aptitudes assessed by standard tests. • Evidence of multiple intelligences is found in people with savant syndrome and autism spectrum disorder (ASD).

6. Theories of Multiple Intelligences (part 2) • Sternberg’s three intelligences • Analytical intelligence (school smarts): Traditional academic problem solving • Creative intelligence (trailblazing smarts): Ability to generate novel ideas • Practical intelligence (street smarts): Skill at handling everyday tasks

7. Gardner and Sternberg • Differences • Gardner identified eight relatively independent intelligences and views these intelligence domains as differentiated multiple abilities. • Sternberg agrees with the concept of multiple intelligences, but proposes three intelligences. • Agreement • Multiple abilities contribute to life successes. • Different varieties of giftedness provide educational challenges for education.

8. Criticism of Multiple Intelligences Theories • Factor analysis confirms the existence of g, which predicts performance on a variety of complex tasks. • Success is more than high intelligence; highly successful people are also conscientious, well connected, and energetic. • Researchers report a 10-year rule: Expert performers spend about a decade in intense, daily practice.

9. Smart and Rich? • Jay Zagorsky (2007) tracked 7403 participants in the U.S. National Longitudinal Survey of Youth for 25 years. Their intelligence scores showed a moderate positive correlation (+30) with their later income.

10. Emotional Intelligence • Four components • Perceiving emotions: Recognizing them in faces, music, and stories • Understanding emotions: Predicting them and how they may change and blend • Managing emotions: Knowing how to express them in varied situations • Using emotions: To enable adaptive or creative thinking

11. Comparing Theories of Intelligence

12. Assessing Intelligence A Few Definitions of Tests • Intelligence test: Method for assessing an individual’s mental aptitudes and comparing them with those of others using numerical scores • Aptitude test: Designed to predict a person’s future performance; aptitude is the capacity to learn • Achievement test: Designed to assess what a person has learned

13. Close Cousins: Aptitude and Intelligence Scores

14. Early and Modern Tests of Mental Abilities(part 1) • Francis Galton • Attempted to assess intellectual intelligence (1884) • Found no correlation between measures • Provided statistical techniques • Believed in the inheritance of genius (discussed in his book Hereditary Genius)

15. Early and Modern Tests of Mental Abilities(part 2) • Alfred Binet • Tended toward environmental explanation of intelligence differences • Assumed all children follow the same course, but not the same rate, of intellectual development • Measured each child’s mental age • Tested a variety of reasoning and problem-solving questions that predicted how well French children would do in school

16. Early and Modern Tests of Mental Abilities(part 3) • Lewis Terman • Revised Binet’s test for wider use in the United States • Extended the upper end of the test’s range • Revision was called the Stanford-Binet • Theorized intelligence tests reveal intelligence with which person is born

17. Early and Modern Tests of Mental Abilities(part 4) David Wechsler: Wechsler Adult Intelligence Scale (WAIS) and Wechsler’s tests for children • Created the most widely used intelligence test today • Yields an overall intelligence score and separate scores for verbal comprehension, perceptual organization, working memory, and processing speed • Available in preschool and school-age child versions • Provides clues to strengths or weaknesses

18. Principles of Test Construction • Three criteria of a “good” test • Was the test standardized? • Is the test reliable? • Is the test valid?

19. Terms to Learn • Standardization: Defining uniform testing procedures and meaningful scores by comparison with the performance of a pretested group. • Reliability: Extent to which a test yields consistent results, as assessed by the consistency of scores on two halves of the test, on alternative forms of the test, or on retesting. • Validity: Extent to which a test measures or predicts what it is supposed to measure or predict. • Content validity: Extent to which a test samples the behavior of interest. • Predictive validity: Success with which a test predicts the behavior it is designed to predict; assessed by computing the validity.

20. The Normal Curve

21. Stability or Change? (part 1) • Cross-sectional evidence for intellectual decline • People of different ages are compared with one another. • Older adults give fewer correct answers on intelligence tests than do younger adults. • Decline of mental ability with age is part of the general aging process.

22. Stability or Change? (part 2) • Longitudinal evidence for intellectual stability • The same people (cohort) are restudied and retested over a long period. • Findings indicate that intelligence remains stable, and on some tests it even increases.

23. Stability or Change? (part 3) • It all depends. • After adjusting for participant loss, a steeper decline in intelligence was revealed, especially after age 85. • Intelligence is not a single trait, but several distinct abilities. • Adjusting for processing speed and using wisdom tests suggest continued intellectual competence in many older adults.

24. Aging and Intelligence • Crystallized intelligence: Accumulated knowledge, as reflected in vocabulary and word-power tests. • Increases as we age, into middle age • Fluid intelligence: Ability to reason speedily and abstractly, as when solving unfamiliar logic problems. • Decreases with age; declines gradually until age 75 and then more rapidly after age 85

25. Cross-Sectional Versus Longitudinal Testing of Intelligence at Various Ages • In this test of one type of verbal intelligence (inductive reasoning), the cross-sectional method produced declining scores with age. • The longitudinal method (in which the same people were retested over a period of years) produced a slight rise in scores well into adulthood. (Data from Schaie, 1994.)

26. With Age, We Lose and We Win

27. Stability Over the Life Span (part 1) • Before age 3: Casual observation and intelligence tests only modestly predict future aptitudes. • By age 4: Intelligence test performance begins to predict adolescent and adult scores. • Late adolescence: Remarkable stability of aptitude scores; +.86 correlation.

28. Stability Over the Life Span (part 2) • Deary and colleagues study • After nearly 70 years of varied life experiences, the test-takers’ two sets of scores showed a striking correlation of +.66. • Johnson study • Scots born in 1936, and tested from ages 11 to 70, confirmed the remarkable stability of intelligence, independent of life circumstance. • When 207 survivors were retested at age 87, the correlation with their age 11 scores was +.51.

29. Intelligence Endures

30. Why Do Intelligent People Live Longer? • Deary (2008) • Intelligence facilitates more education, better jobs, and a healthier environment. • Intelligence encourages healthy lifestyles. • Prenatal events or early childhood illnesses could influence both intelligence and health. • A “well-wired body,” as evidenced by fast reaction speeds, may foster both intelligence and longer life.

31. Extremes of Intelligence • One way to evaluate the validity and significance of any test is to compare people who score at the two extremes of the normal curve. • The low extreme • The high extreme Let’s look at each of these.

32. The Low Extreme of Intelligence (part 1) • Diagnosis of an intellectual disability • Low intelligence test score (70 or below; 2 standard deviations below average) • Difficulty adapting to normal demands of independent living • Conceptual skills • Social skills • Practical skills • In mild forms, intellectual disability, like normal intelligence, results from a combination of genetic and environmental factors (Reichenberg et al., 2016).

33. The Low Extreme of Intelligence (part 2) • Down syndrome • Condition of mild to severe intellectual disability and associated physical disorders caused by an extra copy of chromosome 21 • U.S. Supreme Court (2014) • Recognized the imprecision and arbitrariness of fixed cut-off intelligence scores of 70 • Required states with death row inmates who scored just above 70 on such tests to consider other evidence

34. The High Extreme of Intelligence • Terman study • High-scoring children were healthy, well adjusted, and unusually successful academically. • After many decades, Terman’s group had attained higher levels of education and accolades. • Critics • Question the percentage of gifted children and tracking by aptitude • Suggest enriched gifted education may widen educational gaps • Agree that children have differing gifts that are well served with appropriate developmental placement

35. Genetic and Environmental Influences on Intelligence (part 1) • Do people who share the same genes also share mental abilities? • Intelligence test scores of identical twins raised together are nearly as similar as those of the same person taking the same test twice. • Estimates of the heritability of intelligence (the extent to which intelligence test score variation can be attributed to genetic variation) range from 50 to 80 percent.

36. Intelligence: Nature and Nurture

37. Genetic and Environmental Influences on Intelligence (part 2) • Are there known genes for genius? • Specific genes have been pinpointed that seemingly influence variations in intelligence and learning disorders. • No single DNA segment predicts years of schooling; all genetic variations account for about 2 percent of differences in educational achievement. • Other studies have replicated this modest effect of genes on educational achievement (Belsky et al., 2016). • A British study recently found genes that predicted 9 percent of the variation in school achievement at age 16 (Selzam et al., 2016).

38. Genetic and Environmental Influences on Intelligence (part 3) • Evidence of environment effects • Where environments vary widely, environmental differences are more predictive of intelligence scores (Tucker-Drob & Bates, 2016). • Adoption enhances the intelligence scores of mistreated or neglected children. • Intelligence scores of “virtual twins” (same-age, unrelated siblings adopted as infants and raised together) have a correlation of +.28.

39. Genetic and Environmental Influences on Intelligence (part 4) • Untangling genes and environment • Mental similarities between adopted children and their adoptive families wane with age, until the correlation approaches zero by adulthood. • Identical twins’ similarities continue or increase into their eighties. • In twin pairs in four countries. heritability of general intelligence g increased from 41 percent in middle childhood to 55 percent in adolescence to 66 percent in young adulthood.

40. In Verbal Ability, Whom Do Adopted Children Resemble?

41. Early Environmental Influences • Slowing normal development • McVicker Hunt (1982): Iranian orphanage study found dire, negative effects of extreme deprivation. • Mani and colleagues (2013): Poverty can impede cognitive performance and deplete cognition capacity. • Malnutrition, sensory deprivation, and social isolation slow normal brain development. • Poverty-related stresses impede cognitive performance (Heberle & Carter, 2015).

42. Environmental Influences (part 1) • Schooling and intelligence interact • Head Start increases school readiness and contributes to later health and high school completion rates, but the aptitude benefits fade over time. • Intensive, high-quality preschool programs boost early intelligence scores.

43. Environmental Influences (part 2) • Growth mindset (Dweck, 2006) • Fostered with the belief that intelligence is changeable • Increased when effort rather than ability is encouraged • Made teens more resilient when frustrated by others Ability + opportunity + motivation = success

44. Gender Differences in Intelligence Test Scores (part 1) • Gender similarities and differences • Compared to similarities, gender differences are fairly minor. • Effects of culture • Social expectations and opportunities matter. • Little gender gap found in gender-equal cultures.

45. Gender Differences in Intelligence Test Scores (part 2) • Girls • Outpace boys in spelling, verbal fluency, and locating objects • Are better emotion detectors and are more sensitive to touch, taste, and color • Boys • Outperform girls in tests of spatial ability and complex math problems • Vary in their mental ability scores more than girls do

46. A Mental Rotation Test

47. Racial and Ethnic Similarities and Differences (part 1) • Agreed-upon facts • Racial and ethnic groups differ in their average intelligence test scores. • High-scoring people and groups are more likely to achieve high levels of education and income.

48. Racial and Ethnic Similarities and Differences (part 2) • Genetics research reveals races are alike. • Race is not a clearly defined biological category. • Within the same population, there are generation-to-generation differences in test scores. • Given the same information, Blacks and Whites show similar information-processing skills. • Schools and culture matter. • In different eras, different ethnic groups have experienced golden ages—periods of remarkable achievement.

49. Group Differences and Environmental Impact

50. The Question of Bias • Three hypotheses about racial differences in intelligence: • There are genetically disposed racial differences in intelligence. • There are socially influenced racial differences in intelligence. • There are racial differences in test scores, but the tests are inappropriate or biased.