 Testing and Individual Differences Chapter 11

What is intelligence?  Intelligence – ability to learn from experience, solve problems and use knowledge to adapt to new situations  Intelligence test – a method for assessing an individual’s mental aptitudes and comparing them with those of others, using numerical scores  Charles Spearman (1863 – 1945)  Believed we have one general intelligence (or g) that underlies specific mental abilities and is measureable by every task on an intelligence test  Helped develop factor analysis – statistical procedure that identifies clusters of related items on a test  Used to identify different dimensions of performance that underlie a person’s total score

What is intelligence? -cont-  Raymond Cattell and the Two Subtypes of G  Broke intelligence down into two relatively independent components:  Fluid intelligence – memory, speed of information processing and reasoning abilities  Believed fluid intelligence is innate  Declines with age  Crystallized intelligence – store of knowledge and skills gained through experience and education  Remains stable or increases slightly with age

Theories of Multiple Intelligence  Howard Gardner’s (b. 1943) theory of multiple intelligences  Linguistic  Logical-mathematical  Musical  Spatial  Bodily-kinesthetic  Intrapersonal  Interpersonal  Naturalist  Better explains savant syndrome – condition in which a person otherwise limited in mental ability has an exceptional specific skill

Multiple intelligences -cont-  Robert Sternberg’s three intelligences – believed each was learned  Analytical intelligence – logical reasoning skills that include analysis, evaluation and comparison; assessed by intelligence tests  Creative intelligence – imaginative skills that include developing new inventions and seeing new relationships  Practical intelligence – “street smart” skills that include coping with people and events  Emotional intelligence – ability to perceive, understand, manage and use emotions  Does not include self-esteem or optimism  Some psychologists feel this is stretching intelligence too far

Comparing Theories of Intelligence

Intelligence and the Brain  Intelligence modestly correlates with brain size but the cause is unclear  Highly educated people die with more synapses  Higher intelligence scores have been linked to more gray matter in areas involved in memory, attention and language  Verbal intelligence scores are predictable from the speed people retrieve information from memory  Brain waves of highly intelligence people register a simple stimulus faster and with greater complexity

Assessing Intelligence  Alfred Binet- early 1900s  Goal was to measure a child’s mental age – chronological age that most typically corresponds to a given level of performance  Average 9-year-old has a mental age of 9  Lewis Terman - extended Binet’s work to develop the Stanford-Binet intelligence test  William Stern used these to develop the intelligence quotient (IQ) – ratio of mental age to chronological age, multiplied by 100  Modern IQ tests assign the average performance for a given age a score of 100  2/3 of test takers fall between 85 and 115

Assessing Intelligence -cont-  Achievement tests – tests designed to assess what a person has learned  AP test  Aptitude tests – tests designed to predict a person’s future performance  SAT  Wechsler Adult Intelligence Scale (WAIS) – most widely used intelligence test  Produces a single IQ score but calculates how far a person’s score deviates from scores of others in the same group and plotted on a bell curve

Principles of Test Construction  To be widely accepted, psychological tests must show  Standardization – defining meaningful scores by comparison with the performance of a pretested group  Should be distributed in a normal curve – symmetrical, bell-shaped curve; most scores fall near average with fewer near the extremes  68% fall within one standard deviation above or below the mean  Reliability – extent to which a test yields consistent results – can be determined through:  Test-retest method – researchers compare participants’ scores on two separate administrations of the same test  Split-half method – test is divided into two equivalent parts and researcher determines degree of similarity between scores on the two halves of the test

Principles of Test Construction -cont-  Validity – extent to which a test measures or predicts what it is supposed to  Content validity – extent to which the test samples the behavior that is of interest  Predictive (or criterion) validity – success with which a test predicts the behavior it is designed to predict  Assessed by computing the correlation between test scores and criterion behavior

The Normal Curve

Dynamics of Intelligence: Stability or change?  Except for the extremes, casual observation and intelligence tests before age 3 only modestly predict future aptitudes  Intelligence tests begin to predict adolescent and adult scores by age 4 and stabilize after age 7 Intelligence Endures

The Dynamics of Intelligence: The extremes  The Low Extreme  Intellectual disability – a condition of limited mental ability indicated by an intelligence score of 70 or below and difficulty in adapting to the demands of life  Varies from mild to profound  The High Extreme  Tracking by aptitude may produce a self-fulfilling prophecy – those labeled as “ungifted” may be influenced to become so  Can also promote segregation and prejudice

Degrees of Intellectual Disability

The Nature vs. Nurture of Intelligence  50-75% of intelligence test score variation can be attributed to genetic variation  Intelligence scores of identical twins raised together are almost as similar as the same person taking the test twice  Scores of fraternal twins are much less similar  Adoption enhances the intelligence scores of mistreated or neglected children  Mental similarities between adopted children and their adoptive families decrease with age  Among the poor, environmental conditions can override genetic differences

Intelligence: Nature and Nurture Who do adopted children resemble?

Bias and Intelligence  Stereotype threat – self-confirming concern that one will be evaluated based on a negative stereotype  Blacks have scored higher when tested by Blacks than when tested by whites  Women score higher on math tests when no male test-takers are in the group