The Concept of IQ in History

Francis Galton Sensory responses as indicators of intelligence Charles Spearman g – the beginning of 100 years of research an index of correlated performances Wissler is the first to actually use r to assess correlations among related skills Alfred Binet The first test of intelligence Lewis Terman: Stanford-Binet Intelligence Scale, 1916 David Wechsler: The Wechsler-Bellevue Intelligence Scale, 1938 Scholastic Aptitude Tests (SAT), 1937

Louis Thurston Multiple factors of intelligence based on the “simple structure” of factor analysis Two sides of the same coin J.P. Guilford specific skills and operations of intelligence Howard Gardner A different approach not part of the IQ history. Raymond Cattell and John Horn gF and gC Carroll (1993)’s most comprehensive analysis: g, fluid, crystallized, general memory, visual perception, auditory perception, retrieval ability, speed. Woodcock and Johnson Psych-Educational Battery

Milestones in the Development of the Stanford-Binet and Predecessor Tests __________________________________________________________ YEARTESTS/AUTHORSCOMMENT __________________________________________________________ 1905Binet & SimonClinically useful but poorly standardized; the 30 items did not yield a score! 1908Binet & SimonTwice as long as the 1905 scale, but still poorly standardized; introduced a form of scoring, the mental-age concept. 1911Binet & SimonExpanded to include adults, but still a limited scale. 1916Stanford-BinetBetter standardization (N = 1, 000 children and 400 adults) and IQ concept introduced; Terman & Merrill too much emphasis upon verbal materials.

Milestones in the Development of the Stanford-Binet and Predecessor Tests (Con’t) __________________________________________________________ YEARTESTS/AUTHORSCOMMENT _______________________________________________________ 1937Stanford-BinetFirst use of parallel forms and (2nd Ed )better standardization; test contained 129 Terman & Merrillitems. 1960Standford-BinetParallel forms combined into a single form (3rd Ed )(L-M); extensive checks on item difficulty Terman & Merrill(N = 4,500 children); still too much emphasis on verbal items. 1972ThorndikeRestandardization of the Stanford-Binet (3rd Ed) on 2,100 subjects. 1986Standford-BinetComplete restructuring of the test into 15 (4th Ed )subtests; excellent standardization Thorndike, Hagen, (N = 5,013 persons ages 2-0 to 23-11) & Sattler

___________________________________________________________ A Chronology of the Tests Developed by David Wechsler and Associates ___________________________________________________________ 1939Wechsler-Bellevue Developed at Bellevue Hospital in New York with high hopes that it would help in psychiatric diagnosis. The test consisted of six verbal and five performance subtests. 1946Wechsler-Bellevue II Designed to be an equivalent and alternate form of the Wechsler-Bellevue, this test was never adequately standardized. 1949Wechsler Intelligence Scale for Children A downward extension of the Wechsler-Bellevue II, for children ages 5 to 15 years 11 months. Unfortunately, the standardization sample contained whites only. 1955Wechsler Adult Intelligence Scale A restandardization of the Wechsler-Bellevue with some item revisions, for adults ages 16 and up.

___________________________________________________________ A Chronology of the Tests Developed by David Wechsler and Associates (Con’t) ______________________________________________________________ 1967Wechsler Preschool and Primary Scale of Intelligence For children ages 4 to 6-1/2, the WPPSI was first test to adequately sample racial minorities for the norms Wechsler Intelligence Scale for Children-Revised A revision of the WISC, with updated items especially on Information, Vocabulary, and Picture Completion. The new norms included black and other minorities in appropriate proportion. For children ages 6 to 16 years 11 months. 1981Wechsler Adult Intelligence Scale-Revised A revision of the WAIS, with 80 percent of the original items retained, and updated norms. Verbal and performance subtests alternated.

______________________________________________________________ A Chronology of the Tests Developed by David Wechsler and Associates (Con’t) ______________________________________________________________ 1989Wechsler Preschool and Primary Scale of Intelligence-Revised A revision of the WPPSI with dated and biased items eliminated, for children ages 3 through 7 years 3 months. Object Assembly was added and the norms updated. 1991Wechsler Intelligence Scale for Children-III A revised and renormed version of the WISC-R

Wechsler Adult Intelligence Scale (WAIS-R) 1. Information, not timed (c) 2. Picture completion, timed (?) 3. Digit Span, not timed (f) 4. Picture arrangement, timed (f) 5. Vocabulary, not timed (c) 6. Block Design, timed (f) 7. Arithmetic, timed (f) 8. Object Assembly, timed (?) 9. Comprehension, not timed (c) 10. Digit Span, timed (f) 11. Similarities, not timed (c)

An Integrated View of Intelligence g

Arthur Jenson Philippe Rushton Herrnstein & Murray Put race on the map: Asians, White, and Black

Response Time of 10-year-olds American Children

Sample Size, Mean IQ Score, and Reaction Time Measures (in milliseconds) of 9-year-olds from Five Countries ________________________________________________________________ Hong Japan Britain Ireland South Kong Africa _________________________________________________________________ Sample Size IQ Scores Simple reaction time Choice reaction time Odd-man-out reaction time _________________________________________________________________ Note. Adapted from “IQ and the Wealth of Nations,” by R. Lynn and T. Vanhanen, 2002, p.67, Table 6.2. Copyright 2002 by R. Lynn and T. Vanahanen. Reprinted with permission of the authors.

Means and Standard Deviations of Hong Kong and British Children on Reaction Time Parameters (msec), and Hong Kong – British Differences expressed in Standard Deviation Unit Reaction Time MeasuresHong KongBritishDifference MSDM Simple Reaction Time Movement Time Choice Reaction Time Movement Time Odd man out Reaction Time Movement Time

Performance on mathematics test given at three testing periods (1980, 1984, 1990) for students from Japan ( ), Taiwan( ) and the United States( ) Performance on the reading vocabulary test given at two testing periods (1980, 1990) for students from Japan ( ), Taiwan( ) and the United States( )

Average Cranial Capacities AsianWhiteBlack Unweighted Ms (cm 3 )1, 3911, 3781, 362 Weighted Ms (cm 3 )1, 4251, 3821, 358