Chapter 11 Testing and Individual Differences

Measuring individual differences is an essential component of psychology, but strict guidelines and ethical standards must be followed to ensure results and conclusions are valid and appropriate How Do We Measure Individual Differences?

Validity and Reliability Validity: A property exhibited by a test that measures what it purports to measure  Face validity  Content validity  Item analysis  Criterion validity

Validity and Reliability Reliability: A property exhibited by a test that yields the same results over time  Test-retest reliability  Split-half reliability

Standardization and Norms Scientists use statistics to establish a normal curve This curve can be used to describe most phenomena Normal range: Scores falling near the middle of a normal distribution

Types of Tests Objective tests can be scored easily by machine In subjective tests, individuals are given an ambiguous figure or an open-ended situation and asked to describe what they see or finish a story Inter-rater reliability measures how similarly two different test scorers would score a test

How is Intelligence Measured? Intelligence testing has a history of controversy, but most psychologists now view intelligence as a normally distributed trait that can be measured by performance on a variety of tasks

How is Intelligence Measured? Binet-Simon Test – compared a child’s mental age to his or her chronological age  Current performance, not measure of innate intelligence  Identify those that need help, not to label  Training & opportunity could affect intelligence  Empirical – observed child’s performance U.S. - widespread for the assessment of Army recruits, immigrants, and schoolchildren The Stanford-Binet: standardized its administrations and its age-level norms; most respected

How is Intelligence Measured? Intelligence quotient: Numerical score on an intelligence test, dividing mental age by chronological age and multiplying by 100 (IQ = MA/CA x 100) Problems:  Adults appeared to be mentally retarded!!!  Original IQ has been abandoned in favor of a mental ability score based on performance relative to the average performance of others the same age. Achievement test – measures knowledge of a subject Aptitude test – measures capacity for learning Wechsler (AIS) and (ISC) – less on formal schooling

The Normal Distribution of IQ Scores

The Exceptional Child Mental retardation: Often conceived as representing the lower 2% of the IQ range  Lower than IQ of 70  “significant sub-average intellectual functioning”  Limitations in at least 2 areas Causes  Down Syndrome – genetic  Fetal Alcohol Syndrome - environmental  Phenylketonuria (PKU) – caught early  diet

The Exceptional Child Giftedness: Often conceived as representing the upper 2% of the IQ range  Higher than IQ of 130  Terman (1921) kids w/ IQ 135+ High correlation between IQ and academic performance Healthy, happy, well-adjusted, successful

What Are the Components of Intelligence? Some psychologists believe that the essence of intelligence is a single, general factor, while others believe intelligence is best described as a collection of distinct abilities

Psychometric Theories of Intelligence Psychometrics: mental measurements g Factor: General ability as the main factor underlying all intelligent mental activity (Spearman)  Crystallized intelligence: Knowledge a person has acquired, plus the ability to access that knowledge Increases with age until around 75 (Cattell)  Fluid intelligence: The ability to see complex relationships and solve problems Decreases slowly with age – esp 75+ (Cattell)

What Are the Components of Intelligence? Evidence against the g factor… Savant syndrome: Found in individuals who have a remarkable talent even though they are mentally slow in other domains Kim Peek – Rain Man Stephen Wiltshire

Cognitive Theories of Intelligence Beyond emphasis on vocab, logic, problem solving & other skills to predict school success. Cognitive processes that contribute to success in many areas of life.  Sternberg’s Triarchic Theory  Gardner’s Multiple Intelligences

Sternberg’s Triarchic Theory Practical Intelligence: ability to cope with the environment; aka street smarts Analytical Intelligence: ability to analyze problems and find correct answers; ability measured by most IQ tests; aka logical reasoning Creative Intelligence: form of intelligence that helps people see new relationships among concepts

Cognitive Theories Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Often measured on IQ tests with reading comprehension and vocabulary tests

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Often measured on IQ tests with analogies, math problems and logic problems

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Ability to form mental images of objects and think about their relationships in space

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Ability to perceive and create patterns of rhythms and pitches

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Ability for controlled movement and coordination

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Ability to understand other people’s emotions, motives and actions

Gardner’s Multiple Intelligences Linguistic Logical-Mathematical Spatial Musical Bodily-Kinesthetic Interpersonal Intrapersonal Ability to know oneself and to develop a sense of identity

Gardner’s Three New Intelligences Naturalistic intelligence Spiritual intelligence Existential intelligence

How Do Psychologists Explain IQ Differences Among Groups? While most psychologists agree that both heredity and environment affect intelligence, they disagree on the source of IQ differences among racial and social groups

How Do Psychologists Explain IQ Differences Among Groups? Hereditarian arguments maintain that intelligence is substantially influenced by genetics Environmental approaches argue that intelligence can be dramatically shaped by influences such as  Health  Economics  Education

Heritability and Group Differences Heritability: Amount of trait variation within a group, raised under the same conditions, that can be attributed to genetic differences Heritability says nothing about between-group differences

Heritability and Group Differences Research with twins and adopted children shows genetic influences on a wide range of attributes, including intelligence Research has also shown that racial and class differences in IQ scores can be eliminated by environmental changes