Cognitive Development II Individual Differences in Cognitive Abilities

Cognitive Development II: Individual Differences in Cognitive Abilities This multimedia product and its contents are protected under copyright law. The following are prohibited by law: • any public performance or display, including transmission of any image over a network; • preparation of any derivative work, including the extraction, in whole or part, pf any images; • any rental, lease, or lending of the program.

Measuring Intellectual Power • The First IQ Tests – Alfred Binet and Theodore Simon • 1881, France: adopted ideal of universal education • Needed way to identify children who might have difficulty in school • No accepted definition of intelligence, so tried a broad range of measures • Published first version in 1905 (a revision of that test is still used) – So, IQ tests first developed to predict school success

Measuring Intellectual Power • Power definition (oldest historically) – Quantifiable skill – Measure individual differences • Does not take into account how a problem is solved • Does not describe/explain developmental changes – E. g. , Digit Span (Wechsler subtest) Copyright © Allyn & Bacon 2007

Measuring intellectual power – Lewis Terman revised Binet for use in U. S. (at Stanford, hence “Stanford-Binet”, 1916) • Terman introduced the score Intelligence Quotient (IQ) – Mental age/chronological age X 100 = IQ » So, IQ>100 if MA>CA – 2/3 rds of children are between 85 and 115 Copyright © Allyn & Bacon 2007

IQ Test Score Distribution

Measuring Intellectual Power • Sternberg’s triarchic theory – Analytical intelligence • Remembering, applying facts – E. g. , Who wrote Hamlet? – Calculate the area of a circle. • Type measured by modern IQ, school tests – Creative intelligence • Ability to make unusual connections, process quickly in novel situations – Practical Intelligence • “Street smarts” Copyright © Allyn & Bacon 2007

Changes in IQ Scores • Both maturational and environmental variables influence IQ scores • Secular trend (Flynn effect) – Historical shift upward of IQ Scores • Maturational influences (e. g. , health and nutrition improvements) • Environmental influences (e. g. , Sesame Street, increased preschool attendance, more “testwise”) Copyright © Allyn & Bacon 2007

Modern IQ tests • Most still typically adhere to the power definition of intelligence • Most commonly used are: – Wechsler tests • WPPSI-III (2002) – ages 2: 6 to 7: 3 • WISC-IV (2003) – ages 6 to 16 – Stanford-Binet (2003) – ages 2 to 85+ Copyright © Allyn & Bacon 2007

Wechsler Intelligence Scales for Children • Full Scale IQ score – Composed of 4 Indexes • Verbal comprehension – e. g. , vocabulary, information questions • Perceptual reasoning – e. g. , Rubic’s cube-type tasks • Processing speed – e. g. , quickly recognizing shapes of varying complexity as same or different • Working memory – e. g. , retaining a list of digits and re-organizing them for repetition in reverse order. Copyright © Allyn & Bacon 2007

Wechsler Intelligence Scales for Children • Advantages relative to the Binet – Comparable tasks across the age range – Canadian norms • Disadvantage relative to the Binet – Limited floor and ceiling: • Floor: fewer easy items (lower IQ limit 40) • Ceiling: fewer difficult items (maximum IQ 160) • So, not as good a test for extremely limited or gifted children Copyright © Allyn & Bacon 2007

Stanford-Binet 5 • Disadvantage relative to the Wechsler – Tasks not comparable across the age range • Advantage relative to the Wechsler – Less floor and ceiling effect: • Lower floor: more items that are easy on the Binet (more items a very limited child can answer) • Higher ceiling: more items that are difficult on the Binet (more challenging for gifted examinees). • So, Binet is a better choice for very limited or gifted children Copyright © Allyn & Bacon 2007

Infant IQ Tests • Bayley Scales of Infant Development – Limited to responses infants can make • Measure sensory and motor skill development • Do not predict later IQ test scores or school performance well • Helpful in identifying infants and toddlers with serious developmental delays • Newer tests based on habituation, etc. , are being developed and are likely to improve prediction from infancy, but are not widely available yet. Copyright © Allyn & Bacon 2007

Copyright © Allyn & Bacon 2007

Achievement Tests • Designed to test specific information learned in school Copyright © Allyn & Bacon 2007

Achievement tests • Achievement tests – assess specific information learned in school • IQ tests – originally developed to measure competence • So, can we conclude that IQ measures competence (i. e. , innate capability) and achievement tests measure performance (i. e. , how well capability has been used)? • NO!!!!! Both measure performance Copyright © Allyn & Bacon 2007

Stability of Test Scores • Reliability = the stability of a test score – General trends: stability increases at about age three, becomes quite stable at about age ten. – Longitudinal studies: • Mc. Call, 1993: ~1/2 show no major fluctuation • Caspi et al. , 1996: similar results overall, but added that: – Fluctuations generally are not random, but seem to reflect “bounce” or “rebound” – changes in response to specific life events – Fluctuations less likely after age 10 Copyright © Allyn & Bacon 2007

What IQ Scores Predict • Validity = Whether a test is measuring what it is intended to measure • Correlations between a child’s IQ and current and future academic performance are strong, suggesting that IQ tests are valid for the purpose for which they were developed. • Adult outcome? – findings mixed Copyright © Allyn & Bacon 2007

What IQ Scores Predict • High intelligence – Associated with resiliency – More likely to complete high school and attend college • Low intelligence – Associated with adult illiteracy, delinquency, criminal behavior – May add to a child’s vulnerability • IQ scores do not predict creativity, insight, “street smarts, ” or the ability to read social cues Copyright © Allyn & Bacon 2007

Culture-free or culture-fair tests • Revisions of standard tests (e. g. , removal of U. S. items from Wechsler tests) • Goodenough Draw-a-Person • B. I. T. C. H. • Catell Culture-fair Intelligence Test • Evaluation of culture-fair tests: – Do not predict school success as well – Helpful in some situations Copyright © Allyn & Bacon 2007

Practical application • Case study #1: – 12 -year-old male with academic, behavior problems at school – failed 5 th grade – family intact, structured, no behavior problems at home • WISC: Full Scale 95 (average 90 -110) – Verbal 85; Perceptual 108 • Achievement: Reading 68, Spelling 67 • e. g. , rom (arm), coit (shout), mtrey (material) • Measures of emotional, behavioral adjustment within normal limits • “diamond” heard as “dime and” Copyright © Allyn & Bacon 2007

Practical application • Case study #2: – 7 -year-old male with reading disability referred after threatening to kill self with kitchen knife – verbally precocious, but with significant academic and social problems – family intact and supportive • WISC: Verbal 138; Perceptual 100 (average 90 -110) • Achievement: Reading 85 Copyright © Allyn & Bacon 2007

Explaining Individual Differences in IQ Scores • Heredity – Identical twins are more like each other than fraternal twins – Adopted children’s IQs are similar to that of natural parents • Environment – Adopted children’s IQs also related to that of adoptive parents (e. g. , higher than expected when adopted into higher SES family) – Capron and Duyme – French study with children from higher vs. lower SES background adopted into higher vs. lower SES families: Table 7. 3 in text shows influence of both heredity and environment on these children. Copyright © Allyn & Bacon 2007

Social Class Differences Figure 7. 2 Copyright © Allyn & Bacon 2007

Specific Family Characteristics and IQ Scores • Parents of children who have higher IQ scores – Provide an interesting and complex physical environment – Are emotionally responsive to and involved with their children – Talk to their children often – Operate in the child’s zone of proximal development (Vygotsky) – Avoid excessive restrictiveness, punitiveness, or control – Expect their children to do well and to develop rapidly Copyright © Allyn & Bacon 2007

Differences in Environments within Families • First born children have the highest IQ scores – Scores decline with birth order – Children born close together have lower scores – Confluence model (Zajonc) • Each new child “dilutes” intellectual level of household • Research evidence: 3 -adult families, single-parent families – Namesaking – the practice of first born sons being named after fathers • Higher expectations for success • Higher levels of support Copyright © Allyn & Bacon 2007

Figure 7. 3 Copyright © Allyn & Bacon 2007

School Experience and Special Interventions • Cumulative deficit – disadvantaged children fall further and further behind over time • Head Start – U. S. , 1965; Aboriginal Head Start – Canada, 1995 – Early intervention for economically disadvantaged children • Provide intellectual stimulation for a year or two of preschool • Short term: show a gain of about 10 IQ points, but it is temporary (facilitation) • Long term – Children are less likely to be placed in special education, repeat a grade – More likely to graduate from high school Copyright © Allyn & Bacon 2007

School experiences and special interventions • Perry Preschool Project – – Intensive program for 3 and 4 -year-olds & their families (e. g. , teaching parents to read to their children) – At age 40, many advantages relative to control group (education, income, law-abiding behavior, family life, etc. ) • Enriched infancy programs (1980’s, 1990’s) • Earlier, more intensive interventions • E. g. , Ramey: 8 hours, 5 days a week • Long-term effect on IQ (attunement) Copyright © Allyn & Bacon 2007

School experiences • Teacher expectations – Rosenthal – “Pygmalion in the Classroom” classic study • Teachers given different expectations based on test results (actually, children randomly assigned to group designated as destined to excel) • Predictions were supported • Self-fulfilling prophecy Copyright © Allyn & Bacon 2007

Interactions of Heredity and Environment • World-wide studies show that about half the variation in IQ scores within any population is due to heredity • Heredity/environment interaction (plant growing analogy) • Reaction range – Genes place upper and lower boundaries on IQ (~20 -25) – E. g. , 75 (borderline) to 100 (average) Copyright © Allyn & Bacon 2007

Explaining Group Differences in IQ or Achievement Test Scores • Overlap between groups much larger than small differences between groups • Differences between groups are well within the reaction range of scores that are possible with different environments • Adoption studies support an environmental interpretation Copyright © Allyn & Bacon 2007

Explaining Group Differences in IQ or Achievement Test Scores • Subtle test bias and cultural influences on test performance and classroom experiences – Stereotype threat: anxiety when cultural stereotype predicts poor performance – E. g. , elderly person taking a memory test – Studies show that individuals experiencing stereotype threat show decrements in performance. Copyright © Allyn & Bacon 2007

Figure 7. unf 2 Copyright © Allyn & Bacon 2007

Cultural test bias • Test revisions have not eliminated test bias, but children come from different cultural/ethnic backgrounds • Cross-cultural assessment (e. g. , communication style may not match testing and classroom expectations of majority culture) – Navajo children – Native Hawaiian children – Bilingual Canadian youth – If speak French at home, disclose more in French Copyright © Allyn & Bacon 2007

Cultural test bias • Brice-Heath (anthropologist) – observations in low SES black homes, classroom, and teachers’ homes in southeastern U. S. – Knowledge-training vs. “real” questions – Topic-focused vs. topic-associating styles – Collaborative vs. hierarchical styles – Home vs. school conflict, decreasing participation • Classroom innovations Copyright © Allyn & Bacon 2007

Sex Differences • No consistent differences in total IQ scores – Girls are slightly better at verbal skills – Boys are slightly better at • numerical reasoning – Math differences are magnified in high school – May reflect parental emphasis on math for boys • Spatial visualization (Figure 7. 6) • Measures of mental rotation – Both help in route learning – Distribution of sex scores overlap – Spatial differences may be influenced by prenatal hormonal differences Copyright © Allyn & Bacon 2007

Figure 7. 5 Copyright © Allyn & Bacon 2007

Alternative Views of Intelligence • Information-Processing Theory – Speed of Information Processing • Faster reaction times on speed of performance of simple tasks correlate with higher IQ scores • Biological link to fast central nervous system functioning and higher IQ • Research on children suggest speed differences may be inborn Copyright © Allyn & Bacon 2007

Gardner’s Multiple Intelligences Copyright © Allyn & Bacon 2007

Cognitive Development II: End Show Individual Differences in Cognitive Abilities This multimedia product and its contents are protected under copyright law. The following are prohibited by law: • any public performance or display, including transmission of any image over a network; • preparation of any derivative work, including the extraction, in whole or part, pf any images; • any rental, lease, or lending of the program. Copyright © Allyn & Bacon 2007