unit ix
Unit XI
Module 60 Introduction to Intelligence
Is Intelligence One General Ability?
Charles Spearman:
Proposed a single general intelligence (g) underlying all intelligent behavior.
Based this idea on factor analysis, a statistical method identifying clusters of related abilities.
Noted that individuals scoring high in one ability (e.g., verbal intelligence) often score above average in others (e.g., spatial or reasoning).
Controversial then and remains so today.
L. L. Thurstone:
Identified seven primary mental abilities:
Word fluency
Verbal comprehension
Spatial ability
Perceptual speed
Numerical ability
Inductive reasoning
Memory
Criticized Spearman’s single intelligence score, instead using these separate clusters.
Studies later revealed that people excelling in one cluster often excel in others, suggesting some evidence for g.
General Intelligence (g):
Combines distinct abilities through the coordinated activity of specific brain networks.
Described as a unified distribution of mental resources for various tasks.
Gardner’s Multiple Intelligences
Howard Gardner proposed eight relatively independent intelligences:
Verbal-linguistic: Language proficiency and effective use of words.
Logical-mathematical: Logical reasoning and problem-solving.
Spatial-visual: Using visual imagery to solve problems.
Bodily-kinesthetic: Skillful body movements and coordination.
Musical: Sensitivity to pitch, rhythm, and tone.
Interpersonal: Understanding others' emotions, intentions, and desires.
Intrapersonal: Deep self-awareness and emotional regulation.
Naturalist: Identifying and categorizing elements of the natural world.
Proposed a possible ninth intelligence:
Existential intelligence: Reflecting on life’s profound questions.
Key ideas:
Intelligence domains vary and operate independently.
Brain damage might impair one ability while leaving others intact.
Sternberg’s Triarchic Theory
Robert Sternberg:
Proposed three intelligences contributing to real-world success:
Analytical intelligence: Logical problem-solving, tested in traditional IQ tests.
Creative intelligence: Innovative thinking and adaptation.
Practical intelligence: Everyday problem-solving with multiple possible solutions.
Developed new measures with U.S. College Board to assess creative and practical skills, showing improved predictions of college success.
Criticisms of Multiple Intelligence Theories
Research and general intelligence (g):
Confirms that g predicts performance in complex tasks and jobs.
Exceptional cognitive ability correlates with remarkable achievements (e.g., advanced degrees, publications).
Beyond intelligence:
Success depends on grit, connections, energy, and conscientiousness—not just intelligence.
10-year rule: Mastery in various fields requires approximately a decade of intense, daily practice.
Emotional Intelligence
Concept first proposed by Edward Thorndike (1920) as part of social intelligence.
Emotional intelligence consists of four components:
Perceiving emotions: Recognizing emotions in faces, music, and stories.
Understanding emotions: Anticipating emotions and their interactions.
Managing emotions: Expressing emotions appropriately and controlling them in different situations.
Using emotions: Facilitating creativity and problem-solving.
Key insights:
Emotionally intelligent individuals excel in relationships, careers, and parenting.
They are often happier and healthier.
Criticisms:
Some scholars argue that emotional intelligence may stretch the concept of intelligence too far.
Gardner includes interpersonal and intrapersonal intelligences but warns against diluting the meaning of "intelligence" by including traits like creativity and motivation.
Module 61 Assessing Intelligence
Early and Modern Tests of Mental Abilities
Philosophical Context
Societal emphasis differs: collective welfare (family, community) vs. individual opportunity.
Plato: Advocated individualism, noting that natural endowments differ and suit individuals to different occupations.
Francis Galton: Presuming Hereditary Genius
Background: Influenced by cousin Charles Darwin’s theory of natural selection.
Attempted to measure “natural ability” through traits like reaction time, sensory acuity, and body proportions.
Failures:
No correlation between measures and intellectual strengths.
High-performing adults/students did not consistently outperform others.
Contributions:
Introduced statistical techniques still in use.
Demonstrated how personal biases can influence scientific research.
Alfred Binet: Predicting School Achievement
Developed intelligence tests in early 20th-century France to identify schoolchildren needing special attention.
Assumptions:
All children follow the same intellectual developmental course at varying rates.
Mental age reflects a child’s intellectual performance relative to typical chronological age.
Testing:
Designed questions assessing reasoning and problem-solving, first tested on Parisian schoolchildren.
Beliefs:
Intelligence reflects a general aptitude.
Environmental factors significantly influence development (advocated “mental orthopedics” for attention and self-discipline improvement).
Concerns:
Feared misuse of intelligence tests for labeling and limiting opportunities.
Lewis Terman: Measuring Innate Intelligence
Adaptation: Revised Binet’s test into the Stanford-Binet, extending it for adults.
Introduced the IQ formula:
IQ = (Mental Age ÷ Chronological Age) × 100.
Worked well for children but not adults. Modern tests now assess performance relative to age peers.
Beliefs:
Intelligence as an inborn trait.
Advocated intelligence testing for vocational placement and eugenics, aiming to reduce “feeble-mindedness.”
Applications:
U.S. government used tests to assess immigrants and WWI army recruits, leading to first mass intelligence testing.
Results revealed biases, emphasizing cultural and educational influences.
David Wechsler: Testing Separate Strengths
Created:
Wechsler Adult Intelligence Scale (WAIS).
Wechsler Intelligence Scale for Children (WISC) and preschool versions.
Latest WAIS edition includes 15 subtests, such as:
Similarities: Commonality between objects/concepts.
Vocabulary: Naming or defining objects/words.
Block Design: Visual abstract reasoning.
Letter-Number Sequencing: Sorting numbers/letters in order.
Standardization
Process:
Tests are pretested with representative groups to establish norms.
Individual scores are compared to standardized distributions.
Bell Curve (Normal Curve):
Average score = 100.
68% of scores fall between 85 and 115.
High scores (130+) represent top 2.5%; low scores (below 70) represent bottom 2.5%.
Flynn Effect
Rising intelligence test scores observed worldwide over decades.
Average score in 1920 was 76 compared to today’s 100.
Possible Causes:
Environmental shifts requiring new mental skills.
Counters concerns about declining intelligence due to higher birthrates among lower-scoring populations.
Reliability
Definition: The extent to which a test produces consistent results, regardless of who takes it or when.
Methods to Check Reliability:
Split-half reliability: Dividing the test and comparing the results.
Alternative forms: Using different versions of the test to check consistency.
Test-retest reliability: Administering the same test multiple times and comparing scores.
Findings: Intelligence tests are highly reliable after early childhood. Retested scores usually correlate closely with the initial scores.
Validity
Definition: The extent to which a test measures or predicts what it claims to.
Types:
Content Validity:
Pertains to how well a test represents the relevant behavior.
Examples:
Road tests for driver’s licenses assess real-life driving tasks.
Course exams measure mastery of course material.
Predictive Validity:
Measures how well a test predicts future performance.
Performance by Age:
Children (Ages 6–12): Aptitude test scores strongly predict school performance (correlation ≈ +0.6).
Older Students: Predictive power weakens with age.
Test Performance Correlation:
Intelligence scores correlate more closely with achievement tests.
SAT: Limited predictive success for first-year college grades.
Graduate Record Examination (GRE): Modest correlation with graduate school performance (≈ +0.4).
Issues with Predictive Validity:
When tests are validated with a wide range of scores, but later applied to narrower ranges, predictive power diminishes.
Grade Inflation: Less diverse high school grades predict college grades no better than SAT scores.
Module 62 The Dynamics of Intelligence
Aging and Intelligence
Cross-sectional Studies:
Older adults perform worse on intelligence tests compared to younger adults.
Led David Wechsler to conclude that mental ability declines with age, influencing corporate retirement policies.
Longitudinal Studies:
Retested the same cohort over years and found intelligence remained stable until late in life. Some scores even increased.
Results depend on the type of intelligence assessed:
Crystallized intelligence (accumulated knowledge): Increases with age.
Fluid intelligence (reasoning speed and abstract thinking): Declines starting in the 20s–30s, accelerating after age 75.
Age-Related Cognitive Gains:
Older adults excel in social reasoning: multiple perspectives, offering wisdom, making less emotionally biased decisions.
Cognitive differences explain trends:
Scientists/Mathematicians peak in their 20s–30s (fluid intelligence).
Authors/Philosophers peak later in life (crystallized intelligence).
Stability Over the Life Span
Intelligence tests before age 3 only modestly predict future aptitudes.
By age 11, intelligence scores show remarkable stability:
Scottish Cohort Study (1932):
Intelligence tests administered to 11-year-olds correlated strongly with scores retested at ages 80 and 90.
Results independent of life circumstances.
Why Intelligent People Tend to Live Longer (Ian Deary’s four hypotheses):
Higher intelligence leads to better education, jobs, and environments.
Intelligence fosters healthier living (e.g., less smoking, better diet).
Prenatal/childhood health influences both intelligence and health.
Faster reaction speeds may indicate well-wired bodies, supporting longevity.
The Low Extreme: Intellectual Disability
Criteria for Diagnosis:
Low intellectual functioning (score ≤ 70, bottom 3%).
Difficulty adapting to independent living, assessed in:
Conceptual skills: Language, numbers, time.
Social skills: Interpersonal responsibility, law adherence.
Practical skills: Personal care, occupational ability.
Intellectual disability results from genetic and environmental factors.
Flynn Effect:
Rising test scores periodically lower the cutoff for intellectual disability.
After restandardization, those scoring near 70 may lose points and gain eligibility for special services.
Legal Implications:
2002: U.S. Supreme Court ruled execution of people with intellectual disabilities as unconstitutional.
2014: States required to consider more evidence for borderline cases.
The High Extreme: Giftedness
Lewis Terman’s Study (1921):
Studied 1500 children with IQs > 135 ("Termites").
Findings:
Healthy, well-adjusted, academically successful.
Many achieved high education and professional success (e.g., doctors, lawyers), but none became Nobel laureates.
Gifted Education:
Programs often segregate high-achievers, providing them specialized opportunities.
Criticisms:
May label others as "ungifted," widening achievement gaps.
Minority and low-income students disproportionately placed in lower groups, fostering segregation.
Agreement among critics and supporters:
Children have diverse talents; education should cater to individual strengths for equity and excellence.
Module 63 Studying Genetic and Environmental Influences on Intelligence
Twin and Adoption Studies
Heritability of Intelligence:
Identical twins raised together show extremely similar intelligence scores (almost as if retaking the same test).
Heritability estimates range from 50% to 80%.
Brain scans reveal that identical twins have similar gray and white matter volumes and nearly identical activity in verbal/spatial intelligence regions.
Intelligence is polygenetic, involving many genes; only 2–9% of educational achievements are explained by specific gene variations.
Environmental Influences:
Environmental variations (e.g., among less-educated families) are more predictive of intelligence scores.
Adoption boosts intelligence:
Adopted children from poverty into middle-class homes score ~4.4 points higher than biological siblings left in poverty (Swedish study).
Neglected children in poverty show cognitive improvements post-adoption.
“Virtual twins” (unrelated siblings raised together): Modest score correlation of +0.28.
Genes vs. Environment Over Time:
Adopted children’s intelligence scores increasingly resemble their biological parents rather than adoptive parents as they age.
Heritability of intelligence grows with age (from 30% in early childhood to >50% in adulthood).
Identical twins show stable or increasing intelligence similarities into their 80s.
Early Environmental Influences
Severe Deprivation:
Studies (e.g., Iranian orphanages) highlight how extreme neglect stunts intellectual development.
Children exposed to deprivation often lack basic developmental milestones (e.g., sitting, walking).
Hunt’s Intervention:
Trained caregivers in destitute Iranian orphanages to engage with infants via language-based games, fostering cognitive growth:
Results: Infants could name over 50 objects by 22 months and attracted adoption interest.
Poverty-Related Stress:
Impoverished conditions consume cognitive bandwidth (worry, distraction), impeding performance.
No environmental “recipe” exists to turn normal infants into geniuses, though enriched environments (normal sights, sounds, speech) are necessary.
Early Intervention
Schooling and Intelligence:
Intelligence interacts with education, enhancing future income.
Hunt’s findings inspired Project Head Start (1965):
Government-funded preschool for children below the poverty line.
Results: Increased school readiness and modest boosts in health and graduation rates.
Limitations: Aptitude benefits fade over time.
Post-Babyhood Programs:
Intelligence scores rise with:
Nutritional supplements for mothers/newborns (+3.5 points).
Quality preschool programs (+4 points).
Interactive reading programs (+6 points).
Growth Mindset
Carol Dweck’s Research:
Intelligence is seen as changeable with effort, fostering a growth mindset focused on learning.
Teaching teens the “brain as a muscle” concept encourages resilience and hard work.
Praising effort and perseverance fosters stronger connections between effort and success.
Predictors of Achievement:
Ability + Opportunity + Motivation = Success.
Studies highlight that motivation and study skills rival natural aptitude in academic achievement.
Cultural beliefs, like the South Asian-American emphasis on effort, influence success:
Example: South Asian-Americans dominated U.S. spelling bees (2008–2016).
Criticisms:
Overemphasis on positive thinking can risk blaming disadvantaged individuals for systemic challenges.
Module 64 Group Differences and the Question of Bias
Gender Similarities and Differences
General Intelligence (g): No significant difference between males and females.
Females’ Strengths:
Excel in spelling, verbal fluency, locating objects, detecting emotions, and sensitivity to touch, taste, and color.
Males’ Strengths:
Better at spatial ability and solving complex math problems, though overall math performance is similar between genders.
Mental ability scores show greater variability—more boys are found at both extremes (low and high scores).
Spatial Ability:
Male advantage often attributed to mental rotation of 3D objects.
Evolutionary perspective: Ancestral men required spatial skills for tracking and hunting, while women benefited from locating food resources.
Cultural and Social Influences:
Preferences for math-intensive careers reflect cultural norms.
Gender-equal cultures (e.g., Sweden, Iceland) show smaller gender math gaps compared to gender-unequal cultures (e.g., Turkey, Korea).
Since the 1970s in the U.S., increasing gender equity has reduced the boy-to-girl ratio of high SAT math scorers (from 13:1 to 3:1).
Racial and Ethnic Similarities and Differences
Group Average Test Score Differences:
Racial/ethnic groups differ in average intelligence test scores.
Example: White Americans have historically outscored Black Americans; however, this gap has narrowed, especially among children.
Key Insights:
Individual intelligence differences are partly genetic.
Group differences are primarily environmental (e.g., education, culture, access to resources).
Example: Deaf children score lower on verbal-based intelligence tests compared to hearing children exposed to the dominant language.
Race as a Social Construct:
Race lacks clear biological boundaries; social scientists view it as culturally constructed.
Mixed ancestries and self-identification as multiracial challenge traditional racial categories.
Influences on Test Performance:
Better-fed, better-educated, and better-prepared populations outperform earlier generations.
Educational factors and socioeconomic policies (e.g., school time, discipline) significantly impact national and group differences.
Shrinking Gaps:
Equal education reduces racial intelligence gaps.
Studies show Black college students' scores increased during college more than White students', narrowing aptitude differences.
The Question of Bias in Intelligence Tests
Three Perspectives on Racial Differences in Intelligence:
Genetically influenced differences.
Socially influenced differences.
Test-related biases.
Two Definitions of Bias:
Scientific Definition:
Refers to test validity—whether the test predicts future behavior equally across groups.
Most major aptitude tests (e.g., SAT) are not biased by this definition, as their predictive validity applies across gender, racial, and socioeconomic groups.
Popular Definition:
Bias exists if tests reflect cultural experiences rather than innate ability.
Example: Early 20th-century Eastern European immigrants scored poorly on culturally loaded questions, leading to misclassification as "feebleminded."
Cultural Influence on Testing:
Tests often measure developed abilities influenced by prior education and experiences.
Nonverbal tasks (e.g., digit-span tests) still show racial group differences.
Test-Maker Expectations:
Tester bias may affect the construction and administration of tests.
Stereotypes and attitudes can influence both test-takers’ performance and administrators' interpretations.
Stereotype Threat
Definition: A self-fulfilling concern that one might confirm a negative stereotype about their group, impacting performance.
Key Findings:
Women underperformed on a math test unless they were told beforehand that women perform as well as men.
Black students scored lower on verbal aptitude tests when reminded of their race beforehand.
Self-doubt and self-monitoring triggered by stereotypes hijack working memory, impairing attention and learning.
When the stereotype threat is removed, minorities and women often perform better.
Examples:
Black students score higher when tested by Black teachers rather than White teachers.
Women perform better on math tests in the absence of male test-takers.
Women’s online chess performance drops significantly when they believe they are playing a male opponent.
Stereotype Effects on Academic and Professional Potential
Negative stereotypes:
Undermine self-esteem and long-term academic performance.
Lead students to detach self-worth from academics and seek recognition in other areas.
Interventions:
Encouraging students to believe in their potential increases their sense of belonging.
Viewing intelligence as malleable improves disadvantaged students’ grades and reduces dropout rates.
Bias in Aptitude Tests
Scientific Bias:
Tests are not biased if they validly predict outcomes across all groups (e.g., races, genders).
Major aptitude tests like SATs generally meet this criterion.
Cultural Bias:
Tests are biased if they reflect cultural experiences rather than innate ability.
Example: Early 20th-century Eastern European immigrants, unfamiliar with American culture, were mislabeled as “feebleminded.”
Developed abilities (shaped by education and experience) affect test outcomes, potentially disadvantaging certain groups.
Aptitude Tests and Discrimination
Purpose: To discriminate fairly and objectively for school and job placement.
Eliminating aptitude tests could lead to reliance on subjective criteria, increasing potential for bias (e.g., personal opinions).
Civil service tests were introduced to reduce political, racial, and gender discrimination in hiring practices.
Key Takeaway
Success depends on more than intelligence or test scores:
Competence + Diligence = Accomplishment.
Rationality, practical intelligence, emotional intelligence, and motivation all play crucial roles.
Human adaptability shines through diverse forms of creativity, talent, and effort.