Module 31 Assessing Intelligence Worth Publishers
Assessing Intelligence One-Minute Intelligence Test
Origins of Intelligence Testing • Alfred Binet– French Psychologist • developed intelligence test when schools needed a way to objectively identify students with special needs • believed that all children follow same path of development, some develop more rapidly
Origins of Intelligence Testing • Mental Age • a measure of intelligence test performance devised by Binet • chronological age that most typically corresponds to a given level of performance • child who does as well as the average 8-year-old is said to have a mental age of 8
Origins of Intelligence Testing • Stanford-Binet • the widely used American revision of Binet’s original intelligence test • revised by Terman at Stanford University • extended range to include adults • Developed test to evaluate immigrants and WWI army recruits – cultural bias
Origins of Intelligence Testing • Intelligence Quotient (IQ) • defined originally the ratio of mental age (ma) to chronological age (ca) multiplied by 100 • IQ = (ma/ca x 100) • on contemporary tests, the average performance for a given age is assigned a score of 100
Origins of Intelligence Testing • If mental and chronological age are the same, IQ = 100. • Most current intellectual tests, no longer measure an IQ. • Original formula works for children, not for adults. • Today’s intellectual tests compare mental ability score based on test-taker’s performance relative to the average performance of others that are the same age. • 2/3 of all people score between 85-115.
Assessing Intelligence • Aptitude Test • a test designed to predict a person’s future performance (ex. SAT) • aptitude is the capacity to learn • Achievement Test • a test designed to assess what a person has learned (ex. course exam)
Assessing Intelligence • Wechsler Adult Intelligence Scale (WAIS) • most widely used intelligence test • Subtests – (11) • verbal • performance (nonverbal)
VERBAL PERFORMANCE Picture Completion Picture Arrangement Block Design Object Assembly Digit-Symbol Substitution General Information Similarities Arithmetic Reasoning Vocabulary Comprehension Digit Span From Thorndike and Hagen, 1977 Assessing Intelligence: Sample Items from the WAIS
Assessing Intelligence: Sample Items from the WAIS Subtest of the WAIS-R - Measures abilities to see similarities (Transparency/Analogies)
Assessing Intelligence • To be widely accepted, intelligence tests have to be – • Standardized • Reliable • Valid • (Stanford-Binet, Wechsler tests met all three.)
Assessing Intelligence • Basis for comparing your score to others’ performance – • Give test to a representative group of people. • When people take test their scores are compared to the sample in #1.
Assessing Intelligence • Standardization • defining meaningful scores by comparison with the performance of a pretested “standardization group” • Normal Curve • the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes • most scores fall near the average, and fewer and fewer scores lie near the extremes
Flynn Effect • Greater test sophistication? • Better nutrition? • More education? • More stimulation in the environment? • Less childhood disease? • Smaller families and more parental involvement?
Assessing Intelligence • Reliability • the extent to which a test yields consistent results • assessed by consistency of scores on: • two halves of the test – split test – odd/even • alternate forms of the test • retesting • Validity • the extent to which a test measures or predicts what it is supposed to
Assessing Intelligence Standardized Test Chitlings Test Morris Shoe Size Test – • Are these tests – standardized, reliable, valid?
Assessing Intelligence • Content Validity • the extent to which a test samples the behavior that is of interest • driving test that samples driving tasks • Criterion • behavior (such as college grades) that a test (such as the SAT) is designed to predict • the measure used in defining whether the test has predictive validity
Assessing Intelligence • Predictive Validity • success with which a test predicts the behavior it is designed to predict • assessed by computing the correlation between test scores and the criterion behavior • also called criterion-related validity
10 9 8 7 6 5 4 3 2 1 0 Greater correlation over broad range of body weights Football linemen’s success Little corre- lation within restricted range 180 250 290 Body weight in pounds Assessing Intelligence • As the range of data under consideration narrows, its predictive power diminishes
The Dynamics of Intelligence • Mental Retardation • a condition of limited mental ability • indicated by an intelligence score below 70 • produces difficulty in adapting to the demands of life • varies from mild to profound • Down Syndrome • retardation and associated physical disorders caused by an extra chromosome in one’s genetic makeup