Chapter 8

Intelligence

Defining Intelligence•Binet and Simon

School placement Individual differences

•A single trait—general intelligence (g)

•A few basic abilities:Primary Mental Abilities (Thurstone, 1938)

Word fluency, verbal meaning, reasoning, spatial visualization, numbering, rote memory, and perceptual speed

2 types of intelligenceCrystallized intelligence—factual knowledge of the world

(e.g., word meaning)Tends to increase across the life span

Fluid intelligence—ability to think on the spot (e.g., solve novel puzzles)Tends to peak early in adulthood

•Multiple ProcessesThere are numerous distinct processes, including attending,

perceiving, encoding, planning, and reasoning

Sternberg’s Theory of Successful Intelligence

Analytical Abilities•Traditional intelligence test measures•Language, math, spatial

Creative Abilities•Reasoning in novel circumstances•e.g., creating “clean-up,” a fun game

Practical Abilities•Reasoning about everyday problems •e.g., conflict resolution

Measuring Intelligence•Measuring intelligence is different at different ages

•What’s on a test? Here is an example:

Wechsler Intelligence Test for Children (WISC) (6 and older)

Verbal Section

•Crystallized intelligence•Tests general knowledge•Subtests:

InformationVocabularySimilaritiesArithmeticComprehensionDigit Span

Performance Section

•Fluid intelligence•Tests spatial and perceptual abilities•Subtests:

Picture CompletionPicture ArrangementBlock DesignObject AssemblyCodingMazes

Wechsler Intelligence Test ItemsSUBTEST VERBAL SCALE

Information How many wings does a bird have?

What is a pepper?

Arithmetic If two apples cost $.15, what will be the cost of a dozen apples?

Vocabulary What is does _____ mean? Hammer

Epidemic

Protect

(Adapted with permission from Weschler Intelligence Scale for Children-Third Edition.Copyright © 1991 by The Psychological Corporation)

Wechsler Intelligence Test Items

SUBTEST PERFORMANCE SCALE

Object Assembly Put the pieces below together to make a familiar object

(Adapted with permission from Weschler Intelligence Scale for Children-Third Edition.Copyright © 1991 by The Psychological Corporation)

IQ (Intelligence Quotient)

•IQ is based on a normal distributionMost scores are near the mean (100)

IQ scores fall into a normal distribution like the one shown here. The numbers along the base of the figure correspond to IQ scores. The number just below each IQ score indicates how many standard deviation units that score is below or above the mean; thus, an IQ of 55 is 3 standard deviations below the mean. The percentages in each interval indicate the percent of children whose scores fall within that interval; for example, less than 1% of children have IQ scores below 55 and slightly more than 2% score between 55 and 70.

A normal distribution, shown in both standard deviation units and in the IQ score assigned to that level of performance

Vasta, 3e Fig.10.1

Distribution of IQ Scores in Children

(Figure adapted with permission from Stanford-Binet Intelligence Scale, (3rd ed., p.18) by L.M. Terman and M.A.Merrill, 1973, Chicago: The Riverside Publishing Company. Copyright 1973 © by The Riverside Publishing Company)

•StabilityFrom age 5 correlations of IQ tests at different ages are strong

The closer in age…However,…Stability increases when:…

•IQ predictsAcademic, economic, and occupational successBUT…

Stability of IQAGE 3 6 9 12 18

3 .57 .53 .36 .35

6 .80 .74 .61

9 .90 .76

12 .78

(Based on information from “The Stability of Mental Test Performance Between Two and Eighteen Years”by M.P. Honzik, J.W. MacFarlan, and L. Allen, J. of Experimental Education, 17, p. 325, 1948. Reprinted with permissionof the Helen Reid Educational Foundation. Published by Heldref Publications, 1319 Eighteenth St., N.W., Washington, D.C.20036-1802. Copyright © 1948.)

Effects of IQ and education on income

Factors Influencing Intelligence•The Child

GeneticsPlays a greater role as the child gets older

Evidence

Genotype–Environment Interaction (Scarr 1992)Children overlap with their parents’ interests

(passive effects)

Children influence others’ behaviors (evocative effects)

Children choose things they enjoy (active effects)

Genetic Studies of IQ

Relation Median Correlation

Siblings 0.55

Parent-Child 0.50

Grandparents-grandchild 0.27

First cousins 0.26

Second cousins 0.16

(Adapted from “Genetics and the Development of Intelligence” by S. Scarr-Salapatek, 1975. In F. Horowitz (Ed.),Review of Child Development Research (Vol. 4, p. 33), Chicago: University of Chicago Press. Copyright © 1975 by theUniversity of Chicago Press)

Twin Studies of IQ

Relationship and

Rearing Condition Ave. Corr. # Pairs

Identical twins reared together .86 4,672

Identical twins reared apart .72 65

Fraternal twins reared together .60 5,533

Siblings reared together .47 26,473

Unrelated children reared together .32 714

(Adapted from “Familial Studies of Intelligence: A Review” by T.J. Bouchard, Jr. and M. McGue, 1981, Science, p. 1056. Copyright © 1981 by the American Association for the Advancement of Science)

GenderBoys and girls are mostly equalGirls…Boys…

WHY? Biology? Societal expectations? Peer pressure?

•The Immediate Environment

Family

HOME (Home Observation for Measurement of the Environment, Caldwell & Bradley, 1979)

Components:Emotional and verbal responsivity of motherAvoidance of restrictions and punishmentOrganization of physical and temporal environmentProvisions of appropriate play materialMaternal involvement with childOpportunities for variety of daily stimulation

IQ scores correlate with HOME score

HOME score is predictive of later IQ scores and school achievement

Problem: The HOME is mostly used with biological parents, therefore genetics can not be ruled out

SchoolsMore schooling is correlated with increased IQ scores

IQ scores increase during the school year, but decrease during summer break

•Society

Poverty:

Poor diet, reduced healthcare, inadequate parenting, poor intellectual stimulation, lack of emotional support

at home

In many countries, children from wealthier homes score better on IQ test

The greater the gap in wealth in a country the greater the difference in IQ scores

Resilient children have parents who:Are responsive to the childProvide safe areas to playProvide a variety of learning materials

Relation in three countries between fathers’ occupational status and children’s math achievement

U.S. children whose fathers hold low-status jobs perform far more poorly on math-achievement tests than do children whose fathers hold comparable jobs in Canada or Japan. In contrast, U.S. children whose fathers have high-status jobs perform as well as children whose fathers have comparable jobs in Canada and almost as well as children from similar backgrounds in Japan. (Data from Case et al., 1999)

Race and Ethnicity

More minorities are below the poverty line (socioeconomic status)

Reports are an average for a group, not individual scores within the group

For overall scores and subtests, individual profiles vary

IQ scores only represent a person’s current environment, not his or her potential in different environments

Risk factors and IQ

For both younger and older children, the more risk factors there are in the environment, the lower the average IQ. (Data from Sameroff et al., 1993)

Intervention Programs•Home-Based Programs

Focus on parents and parenting

•Center-Based Programs“Nursery school style”

IQ scores increase then decrease to pre-intervention levels in some research BUT few kids end up in special classes orbeing held back

These programs increase self-esteem, motivation, positive classroom behavior, parenting skills, ability to communicate with teachers which results in better school performance

Reading Skills•Prereading

Children gain basic information by looking (e.g., in English you read left to right)

Letter learning: This skill is not related to later reading achievement

Phonemic Awareness: This skill is related to later abilities to sound out words and better reading

•Word Identification (developmental order)Phonological Recoding: Visual form to speech form to meaningVisually Based Retrieval: Visual form directly to meaning

•ComprehensionThis skill is influenced by basic processes, strategies,

metacognition, content knowledge, amount of reading by self and parents

Writing Skills•Prewriting

A 31/2-year-old’s effort to write a shopping list for a teddy bear

The child’s symbols, although unconventional, indicate an understanding that each word requires a separate symbol. (Jones, 1990)

•Generating WritingRequires:

Low-Level GoalsForming letters, spelling, capitalization, punctuation

High-Level GoalsComprehensive arguments, arguing points,

background information

Mathematics

•PremathDuring the first year, children develop a basic sense of

numbers, limited to small set of itemsBetween 3–4 years old, children begin counting and

understanding the relative size of digitsChildren use a number of strategies, but eventually shift

towards retrieval

•ComprehensionChildren learn procedures before they comprehend whyHigher math achievement comes from understanding

concepts rather than memorizing proceduresThe context of the problem influences a child’s ability to solve it