effectively, and to deal adaptively with the environment Intelligence in Historical Perspective • Sir Francis Galton o Showed through study of family trees that eminence and genius seemed to occur across generations with certain families o Exhibited belief bias, and dismissed fact that successful people often came from privileged environments o Approach to mental skills measurement fell into disfavour because measures of nervous system efficiency proved unrelated to socially relevant measures of mental ability • Alfred Binet o Developed test to help identify children who require educational help at early age o Made two assumptions about intelligence: Mental abilities develop with age Rate at which people gain mental competence is a characteristic of the person and is fairly constant over time o Tests would result in score called mental age (age at which a child can solve problems for) o William Stern provided a relative score called intelligence quotient IQ = (Mental age / Actual age) x 100 o Problem is that increases in mental age begin to slow down dramatically around age 16 o Deviation IQ – modern score that represents how much standardized distance a score is above or below the mean of a particular sample • The Stanford-Binet and Wechsler Scales o Lewis Terman revised Binet’s test, creating the Stanford-Binet test o David Wechsler developed intelligence tests for adults (WAIS), children (WISC), and preschoolers (WPPSI) Most widely used intelligence tests Consists of series of subtests that fall into verbal tests and performance tests • Group tests of aptitude and achievement o Using written tests for selective purposes highlights an issue Binet faced: Should university applicants be given an achievement test (how much they have learned in high school) or an aptitude test (measure applicant’s potential for future learning and performance)? Scientific Standard for Psychological Tests
• Psychological test – a method for measuring individual differences related to some psychological concept, or construct, based on a sample of relevant behaviour in a scientifically designed and controlled situation • Reliability – consistency of measurement o Test-retest reliability – extent to which scores on a presumably stable characteristic are consistent over time o Internal consistency – extent to which an experiment produces clear causal conclusions (will be high when there is no confounding of variables) o Interjudge reliability – extent to which different observers or scorers agree in their scoring of a particular test or observed behaviour • Validity – how well a test actually measures what it is designed to measure o Construct validity – extent to which a test measures the psychological construct (e.g.
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- Spring '09
- Psychology, researcher