Testing and Individual DifferencesChapter 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