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Intelligence and Its MeasurementPsyc 331

1What is Intelligence?Intelligence: a multidimensional concept that is about:Acquiring and applying knowledgeReasoning logically, Planing effectively,Deducting perceptivelyGrasping and visualizing conceptsFinding the right words and thoughtsCoping with novel situations2Historical Discussions:Sir Francis Galton was the first person to publish on the heritability of intelligence.Galton (1883) believed that the most intelligent persons were equipped with the best sensory abilities.By such logic, tests of visual acuity or hearing ability are measurements of intelligence.Galton developed many sensorimotor and perception-related tests by which he attempted to measure his definition of intelligence.

Historical Discussions:Alfred Binet did not define intelligence explicitly but instead described various components of intelligence, including reasoning, judgment, memory, and abstraction.Binet and a colleague criticized Galtons approach to intellectual assessment and instead called for more complex measurements of intellectual ability.While Galton argued that intelligence consisted of distinct processes that could be assessed only by individual tests, Binet viewed intelligence as inseparable abilities that required complex measurements to determine.

Historical Discussions:David Wechsler (1958) conceptualized intelligence as the aggregatecapacity of the individual to act purposefully, to think rationally, and to deal effectively with his environment. It [is] composed of elements or abilities whichare qualitatively differentiable (p. 7).Wechsler was of the opinion that the best way to measure intelligence was by measuring several qualitatively differentiable abilities, which were verbal- or performance-based in nature. The Wechsler-Bellevue (W-B) Scale provided the calculation of a Verbal IQ and a Performance IQ.

Historical Discussions:Jean Piaget focused his research on the development of cognitive abilities in children (i.e., how children think, and how they understand themselves and the world around them).Piaget defined intelligence as an evolving biological adaptation to the outside world; a consequence of interaction with the environment, psychological structures become reorganized.

Intelligence According to a Statistician:Factor-analytic theories of intelligence: focus squarely on identifying the ability or groups of abilities deemed to constitute intelligence.Factor analysis: a group of statistical techniques designed to determine the existence of underlying relationships between sets of variables

Factor-analytic theories of intelligence:Spearman (1927) postulated the existence of a general intellectual ability factor (g) and specific factors of intelligence (s).g was assumed to afford the best prediction of overall intelligence, best measured through abstract-reasoning problems.Group factors: an intermediate class of factors common to a group of activities but not all, neither as general as g nor as specific as s

89-9Two-Factor Theory of Intelligence (Spearman, 1927)

g represents the portion of variance that all intelligence tests have in common and the remaining portions of the variance being accounted for either by specific components (s) , or by error components (e) of this general factor.Factor-analytic theories of intelligence:

Guilford and Thurstone have sought to explain mental activities by deemphasizing or eliminating any reference to g.Gardner developed a theory of seven intelligences: logical-mathematical, bodily-kinesthetic, linguistic, musical, spatial, interpersonal, and intrapersonal.Horn and Cattell developed a theory of intelligence postulating the existence of two major types of cognitive abilities:Crystallized intelligence (Gc): includes acquired skills and knowledge that are dependent on exposure to a particular culture as well as on formal and informal educationFluid intelligence (Gf): nonverbal, relatively culture-free, and independent of specific instructionOther perspectives on intelligence:Information-processing theories: focus on identifying the specific mental processes that constitute intelligence.Simultaneous (parallel) processing: the integration of information occurs all at onceSuccessive (sequential) processing: information is individually processed in a logical sequence

Other perspectives on intelligence:Sternberg (1986) proposed a triarchic theory of intelligence with three principle elements:Metacomponents: involved in planning actions, self-monitoring, and self-evaluationPerformance components: administer the instructions of metacomponentsKnowledge-acquisition components: involved in learning how to do something in the first place (Sternberg, 1994)

How do you measure intelligence?How intelligence is measured largely depends on how the examiner conceptualizes intelligence!

13Tests of IntelligenceThe Stanford-Binet Intelligence ScalesThe first published intelligence test with clear instructions on useThe first test to introduce the concept of an alternate itemRatio IQ: the ratio of the testtakers mental age divided by his or her chronological age, multiplied by 100 to eliminate decimals:

Stanford-Binet Intelligence Scale, Fifth Edition

Tests of IntelligenceThe Stanford-Binet Intelligence Scale, 5th Ed.The Stanford-Binet Full Scale score can be converted into nominal categories designated by cutoff boundaries for quick reference:

Measured IQ RangeCategory145 160 Very gifted or highly advanced130 144 Gifted or very advanced120 129 Superior110 119 High average90 109 Average80 89 Low average70 79 Borderline impaired or delayed55 69 Mildly impaired or delayed40 54 Moderately impaired or delayed

Tests of IntelligenceThe Wechsler TestsA series of individually-administered intelligence tests to assess the intellectual abilities of people from preschool through adulthood.The Wechsler Adult Intelligence Scale, 4th Ed. Contains: 10 core subtests: Block DesignSimilaritiesDigit SpanMatrix ReasoningVocabularyArithmeticSymbol SearchVisual PuzzlesInformationCodingFive supplemental subtests :Letter-Number Sequencing, Figure Weights, Comprehension, Cancellation, and Picture Completion.

10-18Tests of IntelligenceThe Wechsler Intelligence Scale for Children, 4th Ed.The WISC-IV yields a measure of general intellectual functioning (a Full Scale IQ) as well as four index scores: a Verbal Comprehension Index, a Perceptual Reasoning Index, a Working Memory Index, and a Processing Speed IndexIt is also possible to derive up to seven process scoresProcess score: an index designed to help understand the way the testtaker processes various kinds of information10-19

Other Tests of IntelligenceIndividual administrationKaufman Adolescent and Adult Intelligence Test (KAIT)Kaufman Brief Intelligence Test (K-BIT)Kaufman Assessment Battery for Children (K-ABC)Group administrationArmy Alpha testArmy Beta testSchool ability testCalifornia Test of Mental MaturityKuhlmann-Anderson Intelligent TestsHenmon-Nelson Tests of Mental AbilityCognitive Abilities TestsMeasures of Cognitive Style and Specific Intellectual AbilitiesCognitive style: a psychological dimension that characterizes the consistency which one acquires and processes informatione.g., field dependence versus field independenceMeasures of creativityDivergent thinking: a reasoning process in which thought is free to move in many different directions, making several solutions possibleTools tapping creativity include Consequences and Unusual UsesSome Issues: Is intelligence stable?Intelligence in adulthood appears to be relatively stable.Evidence:Gold et al. (1995) compared archival intelligence test data from World War II to intelligence test data acquired 40 years later from a sample of 326 veterans and found stability in measured intelligence over time.Young adult intelligence was found to be the most important determinant of cognitive performance as an older adult.Ivnik et al. (1995) found that verbal intellectual skills tended to be highly stable over time, but newly learned information was much less stable.In later adulthood (beyond age 75 especially), a decline in cognitive ability has been noted.Some Issues:Construct validity

Construct validity depends on how the test developer defined intelligence.If intelligence is defined as Spearmans g, then factor analysis should yield a single large common factor that indicates the different questions or tasks largely reflected the underlying characteristic (g).If intelligence is defined in accordance with Guilfords theory, then no one factor should be expected to dominate, but instead many different factors reflecting a diverse set of abilities. Some IssuesGenderResearch has examined the differences between males and females with regard to cognitive, motor, and other abilities related to intelligence.Some differences have been consistently found but significance is questionable. Males tend to outperform females on tasks requiring visual spatialization, while females tend to excel at language skill-related tasks.Family environmentChildren thrive in a loving home where their safety and welfare are of utmost concern and learning and growth are promoted.The presence of resources, parental use of language, parental expression of concern about achievement, and authoritative parenting may also effect measured intelligence.

Some IssuesCultureCulture provides specific models for thinking, acting, and feeling, enabling people to survive both physically and socially and to master the world around them.Values may differ radically between cultural groups, and thus individuals from these varying cultures may have radically differing views on what constitutes intelligence.Items on an intelligence test tend to reflect the culture of the society where the test is employed and thus many theorists have expressed a desire to develop a culture-free intelligence test.Culture-free intelligence tests are difficult if not impossible, and thus culture-fair intelligence tests began to be developed.Culture loading: the extent to which a test incorporates the vocabulary, concepts, traditions, knowledge, and feelings associated with a particular culture