What is Intelligence?
o psychometric approach: intelligence is a trait or set of traits
on which individuals differ
o early Binet-Simon test: derived mental age but didn’t make
later Stanford-Binet test
o WISC measures intelligence of children
factor analysis: one or many abilities?
analysis of multiple tasks and attempts to determine which
factors are most importantw3
Thurstone’s primary mental abilities
consists of a general ability factor and specialized ability
Caroll’s 3 stratum theory of intelligence
Sternberg’s triarchic theory: more than just about
knowledge— interaction with others, problem solving abilities
Gardner’s theory of multiple intelligences
at least 7 types of intelligence
linguistic, spatial, logical-mathematical, musical, body-
kinesthetic, interpersonal, intrapersonal, naturalist,
more than just IQ score
How is Intelligence Measured?
Standford-Binet Intelligence Scale
o calculated as: mental age/chronological age x100
o modern tests now use Deviation IQs
tests include both verbal and nonverbal (performance)
Bayley Scales of Infant Development
uses developmental quotient
poor predictive value for later IQ How stable are IQ scores across childhood?
scores at age 8 correlate with scores at age 18 (.70)
many children show fluctuations
o increase or decrease; not random
o environment important
o cumulative deficit hypothesis
What do IQ Scores Predict?
o .50 correlation with future grades
health, adjustment, satisfaction
Factors that Influence IQ
evidence for heredity
o twin studies: identical twins’ IQ correlated more than fraternal
o adoption studies: adopted children’s IQ resemble biological
parents more than adopted parents
evidence for environment
Flynn effect: secular trend of IQ
adoption more advantaged family & IQ
parental attitude and child-rearing practices
sociocultural group— values?
home environment— risk factors for low IQ s