1. Theories of Intelligence
Intelligence as a single trait
“g” (general intelligence)

2. Intelligence as a few/several abilities
Ex: fluid vs. crystallized intelligence

3. Intelligence as many processes
Ex: attending, planning, reasoning, problem-solving, language comprehension, etc.

4. Measurement of Intelligence
Most widely used intelligence test for children 6 years and older:
Wechsler Intelligence Test for Children (WISC)
Verbal and Performance sections, each with multiple subtests

5. Verbal Section
Focuses on general knowledge of the world and language skill (mainly crystallized intelligence)
Six subtests
Exs: Information; Vocabulary; Arithmetic

6. Performance Section
Focuses on spatial and perceptual abilities (mainly fluid intelligence)
Six subtests
Exs: Picture Completion; Picture Arrangement; Block Design; Mazes

7. Intelligence Quotient (IQ)
Summary measure of a child’s intelligence relative to other children of the same age
Mean (average score) is always 100, regardless of child’s age
Can compare IQ scores at different ages

9. Stability of IQ Scores
Infant measures of intelligence (developmental quotient measures)
Test mainly perceptual and motor responses
Are not typically correlated with later IQ or school achievement
May help to identify babies with retardation/developmental delays

10. IQ scores are fairly stable from about 5 years of age
The closer in time two tests are, the stronger the relationship between the scores
The older the child at the time of first testing, the better the prediction of later IQ 

11. IQ scores do show some change over time as well
Ex: Average change between 4 and 17 years is 13 points (up or down)

12. IQ Scores as Predictors of Later Development
IQ scores are positively correlated with
School grades and achievement test scores
Years of education completed
Occupational success and income

13. Other important predictors of these outcomes include:
Motivation to succeed
Creativity
Social skills

14. Genetic and Environmental Contributions to IQ Scores
About half the variation in IQ across individuals is related to genetic differences (in the U.S.)
About half is related to environmental differences

16. Texas Adoption Project
Compared two groups of adopted children (adoptive families were above average in income and education)
Biological mothers with IQs below 95 and biological mothers with IQs above 120
Both groups scored above average (>100) on IQ tests in childhood
Children of biological mothers with low IQs had lower IQ scores than children of mothers with high IQs