Stability of and Influences on Intelligence

Module 2.8c: Stability of and Influences on Intelligence

Stability or Change?

  • Aging and Intelligence

    • Two primary types of evidence concerning aging and intelligence:

    • Cross-Sectional Evidence:

      • Suggests a decline in intelligence as age increases.

      • Age groups compared at one point in time to assess intelligence and performance decline.

    • Longitudinal Evidence:

      • Suggests greater stability in intelligence over time.

      • Participants are assessed at multiple points, observing changes over their lifespan.

    • Cohort effects: Refers to variances in intelligence based on the age group being studied, influencing results due to differing experiences.

Comparison of Methods in Aging Intelligence Research

  • Reasoning Ability Scores by Age:

    • Cross-Sectional Method

    • Scores decline from approximately 60 (age 32 years) to 40 (age 74 years).

    • Longitudinal Method

    • Shows no significant decline, indicating more stability with age.

    • Performance graph shows:

    • Age on x-axis, Reasoning ability score on y-axis (ranging from 25 to 60).

Types of Intelligence

  • Crystallized Intelligence:

    • Refers to accumulated knowledge and verbal skills; tends to increase with age.

  • Fluid Intelligence:

    • Involves reasoning abilities and abstract thought; generally decreases in late adulthood.

  • Performance Curve: Graph reflects tests conducted over chronological age with average test-taker's score set at zero.

Stability Over the Life Span

  • Women and IQ: Statistically presented by IQ quartiles, showing different stability across age groups for women in highest vs. lowest IQ quartiles.

    • As age increases, there are significant shifts in intelligence scores across the IQ quartiles, notably the lowest quartile showing different stability trends compared to the highest quartile.

Studying Genetic and Environmental Influences on Intelligence

  • Twin and Adoption Studies:

    • Identical Twin Studies:

    • Help determine the heritability of intelligence and genetic factors.

    • Adoption Studies:

    • Explore environmental impacts on intelligence by comparing adopted children with biological parents versus adoptive parents.

Analyzing Intelligence Scores and Heritability

  • Heritability and Correlation of Intelligence Scores:

    • Intelligence scores correlation for different groups:

    • Identical twins reared together show the highest similarity in intelligence scores.

    • Identical twins reared apart demonstrate slightly lower similarities, indicating environmental influence.

    • Fraternal twins and siblings have even lower correlations, suggesting genetic components in intelligence.

Environmental Influences on Intelligence

  • Early Environmental Influences:

    • Tutored Human Enrichment and Targeted Training: Early-life experiences significantly impact intelligence development.

    • Schooling directly influences cognitive abilities and intelligence.

Growth Mindset vs. Fixed Mindset

  • Growth Mindset: The belief in intelligence as changeable through effort, learning, and experience, promoting resilience and adaptability.

  • Fixed Mindset: The belief that intelligence is innately determined and unchangeable, often leading to a lack of motivation or perseverance in challenges.

Module 2.8d: Group Differences on the Question of Bias

Group Differences in Intelligence Test Scores

  • Gender Differences:

    • Similarities and differences across genders in various cognitive domains:

    • Spelling: Women generally show higher performance.

    • Verbal ability: Females tend to have an edge in standardized testing.

    • Nonverbal ability: Males often outperform in this category.

    • Sensation and Emotion Detection: Women are found superior in interpersonal skills and emotional intelligence.

    • Mathematics and Spatial Aptitudes: Males often perform better in specific mathematical and spatial tasks.

Racial and Ethnic Group Differences

  • Ethnic Similarities and Differences: Variations in cognitive test results across ethnic groups, contributing to the ongoing discourse on intelligence.

The Question of Bias in Testing

  • Two Meanings of Bias:

    • Popular Sense of Bias: Implies unequal treatment or perceived unfairness in the testing process.

    • Scientific Sense of Bias: Concerns whether tests genuinely measure intelligence or are influenced by cultural factors.

    • Test-taker's Expectations: Test performance can be negatively impacted by stereotype threats and preconceived notions about intelligence.

Key Terms and Definitions

  • Intelligence:

    • Defined as the mental quality involving the ability to learn from experience, solve problems, and adapt effectively to new situations.

  • Intelligence Test:

    • A method for evaluating an individual's cognitive abilities via numerical scores compared to others.

  • General Intelligence (g):

    • A construct that represents a, presumably, universal intellectual ability underpinning performance across various cognitive tasks.

  • Factor Analysis:

    • A statistical method to identify relationships among variables and capture the underlying dimensions of performance on intelligence tests.

  • Savant Syndrome:

    • A condition wherein a person displays limited intelligence yet possesses exceptional capabilities in a specific area.

  • Grit:

    • In psychology, grit refers to passion and perseverance in pursuing long-term goals.

  • Emotional Intelligence:

    • The capacity to understand, interpret, manage emotions in both oneself and others.

  • Mental Age:

    • A measure created by Binet representing the chronological age that corresponds to an individual's performance level.

  • Stanford-Binet:

    • The American adaptation of Binet's intel test developed by Terman at Stanford University.

  • Intelligence Quotient (IQ):

    • Originally calculated as IQ = rac{ma}{ca} imes 100 where genetic factors contributed to the measurement.

  • Achievement Tests:

    • Assess what an individual has learned.

  • Aptitude Tests:

    • Are designed to predict future performance based on an individual's current abilities.

  • Wechsler Adult Intelligence Scale (WAIS):

    • Widely employed intelligence test, incorporating both verbal and performance subtests.

  • Standardization:

    • Creating uniform procedures and interpretive benchmarks for testing/categorizing intelligence information.

  • Normal Curve:

    • Describes the probability distribution of scores, typically depicting a bell-shaped curve.

  • Reliability:

    • The consistency of a test in measuring performance over time or among different test versions.

  • Validity:

    • The degree to which a test accurately measures or predicts what it claims to assess.

  • Cohort:

    • A defined group of individuals sharing a common characteristic, often measured over a specific timeframe.

  • Crystallized Intelligence:

    • The totality of acquired knowledge and skills, generally growing with age.

  • Fluid Intelligence:

    • Refers to cognitive abilities that require reasoning in abstract situations, often diminishing in late adulthood.

  • Intellectual Disability:

    • A condition characterized by an IQ score of 70 or below and challenges in performing daily activities.

  • Down Syndrome:

    • A genetic disorder resulting from an extra copy of chromosome 21, associated with a range of mental and physical challenges.

  • Heritability:

    • The measure of how much variation in intelligence among individuals can be attributed to genetic factors.

  • Stereotype Threat:

    • The concern that one may confirm a negative stereotype about a group they belong to, potentially impacting their performance.

  • General Intelligence (g):

    • A construct that represents a, presumably, universal intellectual ability underpinning performance across various cognitive tasks.

  • Factor Analysis:

    • A statistical method to identify relationships among variables and capture the underlying dimensions of performance on intelligence tests.

  • Savant Syndrome:

    • A condition wherein a person displays limited intelligence yet possesses exceptional capabilities in a specific area.

  • Grit:

    • In psychology, grit refers to passion and perseverance in pursuing long-term goals.

  • Emotional Intelligence:

    • The capacity to understand, interpret, manage emotions in both oneself and others.

  • Mental Age:

    • A measure created by Binet representing the chronological age that corresponds to an individual's performance level.

  • Standardization:

    • Creating uniform procedures and interpretive benchmarks for testing/categorizing intelligence information.

  • Normal Curve:

    • Describes the probability distribution of scores, typically depicting a bell-shaped curve.

  • Reliability:

    • The consistency of a test in measuring performance over time or among different test versions.

  • Validity:

    • The degree to which a test accurately measures or predicts what it claims to assess.

  • Cohort:

    • A defined group of individuals sharing a common characteristic, often measured over a specific timeframe.

  • Crystallized Intelligence:

    • The totality of acquired knowledge and skills, generally growing with age.

  • Fluid Intelligence:

    • Refers to cognitive abilities that require reasoning in abstract situations, often diminishing in late adulthood.

  • Intellectual Disability:

    • A condition characterized by an IQ score of 70 or below and challenges in performing daily activities.

  • Down Syndrome:

    • A genetic disorder resulting from an extra copy of chromosome 21, associated with a range of mental and physical challenges.

  • Heritability:

    • The measure of how much variation in intelligence among individuals can be attributed to genetic factors.

  • Stereotype Threat:

    • The concern that one may confirm a negative stereotype about a group they belong to, potentially impacting their performance.

  • Types of Intelligence Tests:

    • Stanford-Binet:

      • The American adaptation of Binet's intelligence test developed by Terman at Stanford University.

    • Intelligence Quotient (IQ):

      • Originally calculated as IQ=maca×100IQ=cama​×100 where mama is mental age and caca is chronological age; genetic factors contributed to the measurement.

    • Achievement Tests:

      • Assess what an individual has learned.

    • Aptitude Tests:

      • Are designed to predict future performance based on an individual's current abilities.

    • Wechsler Adult Intelligence Scale (WAIS):

      • Widely employed intelligence test, incorporating both verbal and performance subtests.