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

3. What Is Intelligence? 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.
General intelligence (g)
General intelligence factor that, according to Spearman and others, underlies specific mental abilities and is therefore measured by every task on an intelligence test.

4. What Is Intelligence? Thurstone’s response Kanazawa (2010)
Fifty-six different tests mathematically identified seven clusters of primary mental abilities.
Researchers found scoring well on one cluster generally matched high scores on the others, providing some evidence of g
Kanazawa (2010)
General intelligence scores do correlate with ability to solve novel problems but not with individual skills in evolutionarily familiar situations

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

6. Theories of Multiple Intelligences
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 Agreement
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. Gardner and Sternberg Criticisms
Factor analysis confirms existence of g that 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. 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
Emotionally intelligent people achieve greater personal and professional success. Some critics question whether calling these abilities “intelligence” stretches that concept too far.

10. Comparing Theories of Intelligence
Theory
Summary
Strengths
Other Considerations
Spearman’s general intelligence (g)
A basic intelligence predicts our abilities in varied academic areas.
Different abilities, such as verbal and spatial, do have some tendency to correlate.
Human abilities are too diverse to be encapsulated by a single general intelligence factor.
Thurstone’s primary mental abilities
Our intelligence may be broken down into seven factors: word fluency, verbal comprehension, spatial ability, perceptual speed, numerical ability, inductive reasoning, and memory.
A single g score is not as informative as scores for seven primary mental abilities.
Even Thurstone’s seven mental abilities show a tendency to cluster, suggesting an underlying g factor.
Gardner’s multiple intelligences
Our abilities are best classified into eight or nine independent intelligences, which include a broad range of skills beyond traditional school smarts.
Intelligence is more than just verbal and mathematical skills. Other abilities are equally important to our human adaptability.
Should all of our abilities be considered intelligences? Shouldn’t some be called less vital talents?
Sternberg’s triarchic theory
Our intelligence is best classified into three areas that predict real - world success: analytical, creative, and practical.
These three domains can be reliably measured.
These three domains may be less independent than Sternberg thought and may actually share an underlying g factor.
Additional testing is needed to determine whether these domains can reliably predict success.
Emotional intelligence
Social intelligence is an important indicator of life success. Emotional intelligence is a key aspect, consisting of perceiving, understanding, managing, and using emotions.
The four components that predict social success.
Does this stretch the concept of intelligence too far?
Table 29.1

11. Assessing Intelligence
First…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
Test designed to predict a person’s future performance; aptitude is the capacity to learn
Achievement test
Test designed to assess what a person has learned

12. CLOSE COUSINS: APTITUDE AND INTELLIGENCE SCORES
Figure 30.1
A scatterplot shows the close correlation that has existed between intelligence scores and verbal and quantitative SAT scores. (From Frey and Detterman, )

13. Early and Modern Tests of Mental Abilities
Francis Galton
Attempted to assess intellectual intelligence (1884)
Found no correlation between measures
Provided statistical techniques
Persisted in belief of inheritance of genius (Hereditary Genius)

14. Early and Modern Tests of Mental Abilities
Alfred Binet
Tended toward environmental explanation of intelligence differences
Assumed all children follow same course, but not the same rate, of intellectual development
Measured each child’s mental age
Tested variety of reasoning and problem-solving questions that predicted how well French children would succeed in school
Binet started the modern intelligence testing movement in France in 1904 when he developed questions to help predict children’s future progress in the Paris school system.

15. Early and Modern Tests of Mental Abilities
Lewis Terman
Revised Binet’s test for wider use in U.S.
Extended upper end of test’s range
Named revision the Stanford-Binet
Theorized intelligence tests reveal intelligence with which person is born

16. Early and Modern Tests of Mental Abilities
David Wechsler: Wechsler Adult Intelligence Scale (WAIS) and Wechsler’s tests for children
Created most widely used intelligence test today
Yields overall intelligence score and separate scores for verbal comprehension, perceptual organization, working memory, and processing speed
Contains preschool and school-age child versions
Provides clues to strengths or weaknesses
These tests differ from their predecessors in the way they offer an overall intelligence score as well as scores for various verbal and performance areas.

17. Getting smarter?
In every country studied, intelligence test performance rose during the twentieth century, as shown here with American Wechsler and Stanford-Binet test performance between 1918 and In Britain, test scores have risen 27 points since (From Horgan, 1995, updated with Flynn, 2012, 2014.)

18. Scores on aptitude tests tend to form a normal, or bell-shaped, curve around an average score. For the Wechsler scale, for example, the average score is 100.
THE NORMAL CURVE
Figure 30.2

19. Principles of Test Construction
Three criteria of a “good” test
Was the test standardized?
Is the test reliable?
Is the test valid?
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.
Content validity
Extent to which a test samples the behavior that is of interest.
Predictive validity
Success with which a test predicts the behavior it is designed to predict; it is assessed by computing the validity.

20. Stability or Change? Phases of Research Development
Phase I: Cross-sectional evidence for intellectual decline
People of different ages are compared with one another
Older adults gave fewer correct answers on intelligence tests than did younger adults
Decline of mental ability with age is part of general aging process

21. Stability or Change? Phases of Research Development
Phase II: Longitudinal evidence for intellectual stability
Research in which the same people (cohort) are restudied and retested over a long period
Myth of sharp intelligence declines with age was debunked

22. 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.)

23. Stability or Change? Phases of Research Development
Phase III: It all depends
After adjusting for participant loss, a steeper decline in intelligence revealed, especially after 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. Stability or Change? Phases of Research Development
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. WITH AGE, WE LOSE AND WE WIN.
Ann Baldwin/Shutterstock
Figure 31.2
WITH AGE, WE LOSE AND WE WIN.
Studies reveal that word power grows with age, while fluid intelligence dimensions decline (Salthouse, 2010b).

26. The Dynamics of Intelligence: Stability Over the Life Span
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

27. Intelligence Across the Life Span: Stability or Change?
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 from ages 11 to 70 confirmed the remarkable stability of intelligence, independent of life circumstance.
When 207 survivors were again retested at age 87, the correlation with their age 11 scores was

28. Why Do Intelligent People Live Longer?
Deary (2008)
Intelligence provides better access to resources.
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.

29. 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.

30. The Low Extreme of Intelligence
To be diagnosed with an intellectual disability
Low intelligence test score (70 or below; 2 standard deviations below average)
Difficulty in adapting to normal demands of independent living
Conceptual skills
Social skills
Practical skills

31. The Low Extreme of Intelligence
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 imprecision and arbitrariness of fixed cut- off scores of 70
Required states with death row inmates who scored just above 70 to consider other evidence

32. 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 percentage of gifted children and tracking by aptitude
Suggest enriched gifted education may widen educational gap
Do agree that children have differing gifts which are well served with appropriate developmental placement

33. Genetics and Environmental Influences on Intelligence
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 (extent to which intelligence test score variation can be attributed to genetic variation) range from 50 to 80 percent.

34. INTELLIGENCE: NATURE AND NURTURE
The most genetically similar people have the most similar intelligence scores. Remember: 1.0 indicates a perfect correlation; zero indicates no correlation at all. (Data from McGue et al., 1993.)
Figure 32.1

35. Genetics and Environmental Influences on Intelligence
Are there known genes for genius?
Specific genes pinpointed that seemingly influence variations in intelligence and learning disorders
No single DNA segment predictor of years of schooling; all genetic variations account for about 2 percent of schooling differences
Gene variation predicted slightly bigger brain

36. Genetics and Environmental Influences on Intelligence
Environment effects evidence
Where environments vary widely, environmental differences are more predictive of intelligence scores
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) correlate +.28

37. Genetics and Environmental Influences on Intelligence
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.

38. Early Environmental Influence
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 slowed normal brain development.

39. Environmental Influences
Schooling and intelligence interact.
Head Start increases school readiness and contributes to later health and high school completion rates; aptitude benefits fade over time
Intensive, high quality preschool programs boost early intelligence scores.

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

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

42. THE MENTAL ROTATION TEST
This is a test of spatial abilities. (From Vandenberg & Kuse, 1978.)
Do you know the answer?

43. Racial and Ethnic Similarities and Differences
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.
Groups differences provide poor basis for judging individuals.

44. Racial and Ethnic Similarities and Differences
Consider…
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.
In different eras, different ethnic groups have experienced golden ages— periods of remarkable achievement.

45. GROUP DIFFERENCES AND ENVIRONMENTAL IMPACT
Even if the variation between members within a group reflects genetic differences, the average difference between groups may be wholly due to the environment. Imagine that seeds from the same mixture are sown in different soils. Although height differences within each window box of flowers will be genetic, the height difference between the two groups will be environmental. (From Lewontin, 1976.)

46. 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.

47. Two Meanings of Bias
Scientific meaning of bias is based on test predictive validity. If test does not accurately predict future behavior for all groups of test- takers, it is biased.
A test can also be biased if it detects not only innate differences in intelligence but also performance differences caused by cultural experiences.
Some researchers suggest use of culture-neutral questions.
Others note that racial group differences exist on nonverbal items

48. Test-Takers’ Expectations
Self-fulfilling stereotype threat is a self- confirming concern that one will be evaluated based on a negative stereotype.
Stereotype threat may impair attention, performance, and learning.
Women do not perform on difficult math test as well as men unless told women usually do as well on the test (Spencer and colleagues, 1997).
Black students performed worse when reminded of their race before the test (Steele and colleagues, 2002).

49. Test-Takers’ Expectations
Stereotype threat does not fully account for Black- White aptitude score differences or the gender gap in high-level math achievements.
It does address why Blacks score higher when tested by Blacks, why women score higher on math tests when no male test-takers are present, and the “Obama effect.”
Conclusion: Aptitude tests are not biased in the scientific sense but they are biased related to insensitivity to differences caused by culture experiences.

50. Competence + Diligence  Accomplishment
Bias—Or Not?
Competence + Diligence  Accomplishment