Chapter 9: Intelligence & Language

Amber GilewskiTompkins Cortland Community College

The Evolution of Intelligence Testing

• Sir Francis Galton (1869) – Hereditary Genius

• Alfred Binet and Theodore Simon (1905)– Binet-Simon Intelligence Scale– Mental age

• Lewis Terman (1916)– Stanford-Binet Intelligence Scale– Intelligence Quotient (IQ) = MA/CA x 100 created by William Stern

• David Wechsler (1939)– Wechsler Adult Intelligence Scale

Factor Theories of Intelligence

• Intelligence is made up of a number of mental abilities (factors)

• Spearman’s g factor– General intelligence– s factor represents specific intelligence

• Thurstone’s eight specific factors– Primary mental abilities

Theories of Intelligence

– Sternberg’s triarchic theory (analytical, creative, practical)– Gardner’s multiple

intelligences (musical, bodily kinesthetic,

logical-mathematical, linguistic, spatial, interpersonal, intrapersonal, naturalist, existential)

– Goleman’s emotional intelligence: understanding emotions in self and others; regulating emotions

Approximate Distribution of IQ Scores

Differences in Intellectual Functioning

• Socioeconomic and Ethnic Differences– Consideration of social class

• Lower-class U.S. children score 10 – 15 IQ points lower than middle- and upper-class

– Consideration of ethnicity• Impact of social class

– Asian Americans more likely to graduate high school and complete college

Do Intelligence Tests Contain Cultural Biases?

• Tests may measure familiarity with dominant middle-class culture

• Culture-free Intelligence Tests– Cattel’s Culture-Fair Intelligence Test– Goodenough’s Draw-A-Person test

• European American children outperform African American children on “culture-free” test

• Steele’s stereotype vulnerability• Ethnic differences vs. social class

Figure 9.17 Genetics and between-group differences on a trait

Gender Differences in Intelligence Tests

• Intelligence tests do not show overall differences in cognitive ability– Girls superior to boys in verbal ability– Boys excel in visual-spatial ability– Boys tend to score higher on math tests

• Group scores represent greater variation within the group than between the groups

Genetic Influences on Intelligence

• Kinship studies – IQ scores of identical twins are more alike

than for any other pairs • Twin Studies

– IQ scores of MZ twins reared together have higher correlation than MZ twins reared apart

• Adoption Studies– Stronger relationship between IQ scores of

adopted children and their biological parents than between children and adoptive parents

Heritability of Intelligence

• Heritability is between 40% and 60%– About half the difference between your IQ

score and the IQ scores of other people can be explained by heredity

• Environment is also important• Being reared together is related to IQ

similarities• Cumulative deprivation hypothesis• Concept of “reaction range”

Findings of Studies of the Relationship between IQ Scores and Heredity

Environmental Influences on Intelligence

• Home Environment– Important predictor of

IQ scores - ages 3 to 8• Education

– Enriched early environments (Head Start)

• Western world – IQ scores rose substantially between 1947 and 2002– Impact of social and

cultural factors• Changes also

demonstrated in subpopulations– Educational gap

between races in U.S. is narrowing

The Flynn Effect

The Complex Web of Factors That Affect Intellectual Functioning