Unit XI: Testing & Individual Differences

Module 60 – Introduction to IntelligenceModule 61 – Assessing IntelligenceModule 62 – The Dynamics of Intelligence Module 63 – Studying Genetic & Environmental Influences on IntelligenceModule 64 – Group Differences & the Question of Bias

60.1 – Defining Intelligence

What is Intelligence?Intelligence (in all cultures) is the ability to learn from experience, solve problems, and use our knowledge to adapt to new situations. In research studies, intelligence is whatever the intelligence test measures, which has tended to be “school smarts.”

60.2 – Is Intelligence One General Ability?

General Intelligence•Charles Spearman (1863-1945) believed we have one general intelligence (g).•He thought that a common skill set, the gf actor, underlies all intelligent behaviorFor example, people who do well on vocabulary examinations do well on paragraph comprehension examinations, a cluster that helps define verbal intelligence.

60.3 – Multiple Intelligences

Gardner’s Multiple Intelligences•Howard Gardner (1983, 1999) supports the idea that intelligence comes in multiple forms. •Gardner notes that brain damage may diminish one type of ability but not others.•People with savant syndrome excel in abilities unrelated to general intelligence.

Sternberg: Multiple Intelligences

Robert SternbergRobert Sternberg (1985, 1999, 2003) also agrees with Gardner, but suggests 3 intelligences rather than 8:1. Analytical Intelligence: Intelligence that is assessed by intelligence tests (academic problem-solving).2. Creative Intelligence: Intelligence that makes us adapt to novel situations, generating novel ideas.3. Practical Intelligence: Intelligence that is required for everyday tasks (e.g. street smarts).

60.4 – Emotional Intelligence

Emotional IntelligenceEmotional intelligence is the ability to perceive, understand, manage and use emotions.

Emotional Intelligence: Criticism•Gardner and others criticize the idea of emotional intelligence•He warns that if we stretch “intelligence” to include everything we prize, it will lose its meaning 60.5 – Brain Size and Complexity

Brain Size and Complexity•Einstein’s brain was average size, but his parietal lobe’s lower region was 15% larger than average (center for

mathematical and spatial information)•Highly educated people die with 17% more synapses•Higher intelligence scores are linked with more gray matter (neural cell bodies) in areas involved in memory, attention, and language

60.6 – Brain Function•People who score high on intelligence tests tend to have agile brains & score high in speed of perception and speed of neural processing

61.1 – Origins of Intelligence Testing

Alfred Binet•Alfred Binet developed questions that would predict children’s future progress in the Paris school system.•He hoped the test would be used to improve children’s education, but also worried that the test would be used tolabel children & limit their opportunities.

Lewis Terman and IQ•In the US, Lewis Terman adapted Binet’s test for American school children and named the test the Stanford-BinetTest. •Then William Stern introduced the following formula to derive a person’s Intelligence Quotient (IQ):

•Today, “IQ” is still used as shorthand to represent an intelligence test score –or a test taker’s performance relative to the average performance of others the same age.

61.2 – Achievement vs. Aptitude Tests

Achievement vs. Aptitude Tests•Achievement tests –measure what a person has learned •Aptitude tests –predict a person’s future performance (aptitude= the capacity to learn)

Wechsler Adult Intelligence Scale•Wechsler developed the Wechsler Adult Intelligence Scale(WAIS) and later the Wechsler Intelligence Scale for Children (WISC), an intelligence test for school-aged children.•It is now the most widely used intelligence test.

WAISWAIS measures overall intelligence and 11 other aspects related to intelligence.

61.3 - Standardization & the Normal Curve

Standardization•Defining uniform testing procedures and meaningful scores by comparison with the performance of a pre-tested group•The group member’s scores typically are distributed in a bell-shaped pattern that that forms the normal curve

Normal Curve

61.4 – Reliability and Validity

Principles of Test ConstructionFor a psychological test to be acceptable it must be standardized, reliable, and valid.•Reliability–the extent to which a test yields consistent results•Validity–the extent to which a test measures or predicts what it is supposed to•General aptitude tests are highly predictive from ages 6-12

62.1 – Stability of Intelligence Scores

Stability Over the Life Span•Before age 3 intelligence tests are not good predictors of future aptitudes •By age 4 scores begin to predict adolescent and adult scores•By age 7 scores become fairly stable and consistent

Aging and Intelligence•Crystalized intelligence, our accumulated knowledge and verbal skills, increases up to old age•Fluid intelligence, our ability to reason speedily and abstractly, tends to decrease during adulthood (slowly at first, more rapidly in late adulthood)

62.2 – Extremes of Intelligence

The Low Extreme•Crystalized intelligence, our accumulated knowledge and verbal skills, increases up to old age•Fluid intelligence, our ability to reason speedily and abstractly, tends to decrease during adulthood (slowly at first, more rapidly in late adulthood)

Intellectual Disability•Down syndrome is a condition of mild to severe intellectual disability caused by an extra copy of chromosome 21 •Individuals with mild intellectual disabilities required constant supervision a few decades ago, but with a supportive family environment and special education many can now care for themselves.

Rosa’s LawPassed in 2010, the law removed the terms "mental retardation" and "mentally retarded" from federal health, education and labor policy and replaced them with “individual with an intellectual disability” and “intellectual disability.”

The High Extreme•Individuals with an IQ score above 135•Many schools provide “talented and gifted” education programs for academic enrichment•Critics argue these programs create a self-fulfilling prophecy for both gifted and “un-gifted” children

MENSA“Membership of Mensa is open to persons who have attained a score within the upper two percent of the general population on an approved intelligence test that has been properly administered and supervised.”

63.1 – Genetic Influences on Intelligence

Genetic Influences•Studies of twins, family members, and adopted children support the idea that there is a significant genetic contribution to intelligence.

Environmental InfluencesStudies of twins and adopted children show the following:1. Fraternal twins raised together tend to show similarity in intelligence scores.2. Identical twins raised apart show slightly less similarity in their intelligence scores.

63.2 – Environmental Influences on Intelligence

Environmental Influences•Malnutrition, sensory deprivation, and social isolation can retard normal brain development•Schooling is an experience that pays dividends: increased schooling correlates with higher intelligence scores.•Having a “growth mindset” results in a focus on learning and growing

64.1 – Gender Similarities and Differences

Gender Differences•Males & females tend to have the same average intelligence test scores, though they do differ in some specific abilities •Girls are generally better spellers, more verbally fluent, and outperform boys in math computation•Boys generally outperform girls at spatial ability and related mathematics•Boys outnumber girls at the low and high extremes of mental abilities

64.2 – Racial and Ethnic Similarities and Differences

Ethnic Similarities and DifferencesTwo disturbing but agreed upon facts fuel the group-differences debate:1. Racial groups differ in their average intelligence scores.2. High-scoring people (and groups) are more likely to attain high levels of education and income.

Racial Similarities and Differences•Races are remarkably alike genetically. •Race is a social category.•Today’s better prepared populations would outperform populations of the 1930s on intelligence tests. •White and black infants tend to score equally well on tests predicting future intelligence.•Different ethnic groups have experienced periods of remarkable achievement in different eras.•Schools & culture matter.

64.3 – The Question of Bias

Bias in Intelligence Tests•Aptitude tests are biased in the sense that they are sensitive to performance differences caused by cultural experience •Intelligence tests do, however, predict future behavior, so psychologists overwhelmingly agree that these aptitude tests are not biased

Test-Takers Expectations•A stereotype threat is a self-confirming concern that one will be evaluated based on a negative stereotype •This phenomenon appears in some instances in intelligence testing among African-Americans