Intelligence
Definitions of Intelligence
Dictionary definition: “faculty of thought and reason”
What behaviors are typical of intelligent people?
1.
2.
3.
What behaviors are typical of intelligence at: 6 months
2 years
10 years?
Alfred Binet: The holistic view
Asked people to apply functions of intelligent behavior:
memory,
judgment, abstraction.
Devised test of “general mental ability”:
• First developmental test:
Items classified by age at which child could do them.
Tasks on intelligence tests are positively correlated:
Overall scores correlate with school grades, test performance, information-processing speed, knowledge of
non-studied subjects, and speed of neural transmission
A few basic abilities:
v
Word
fluency, verbal meaning, reasoning, spatial
visualization, numbering, rote memory, and perceptual speed
v
Tests
for a single ability correlate more than with tests
for other abilities
Cattell: “g” is two factors
v
Crystallized
intelligence—factual
knowledge of the world
(e.g., word meaning)
è
Tends to
increase across the life span
v
Fluid
intelligence—ability to
think on the spot
(e.g., solve novel puzzles)
è
Tends to
peak early in adulthood
v
Tests
for each intelligence
Carroll:
Three-stratum Theory:
“g” is top of a pyramid, with 8 abilities below.
|
“G” |
|||||
|
Fluid I |
Crystallized I |
Memory, Learning |
Visual Perception |
Retrieval Ability |
Processing speed |
|
Induction Reasoning |
Vocabulary comprehension |
Memory span |
Spatial relations |
Creativity, Naming |
Reaction time |
• Language skill
• Musical skill
• Logical skill
• Spatial skill
• Existential
• Kinesthetic, or body balance, skill
• Interpersonal and intrapersonal skills
• Naturalistic - see patterns
Intelligence Tests for Children
Stanford-Binet Intelligence Scale (2-adult)
Measures general intelligence and four factors:
• Verbal, Quantitative, Abstract/visual reasoning + ST memory
Supposed to be sensitive to culture and gender
IQ
n
Stanford-Binet gives overall
quantitative measures of a child’s intelligence relative to that of other
children of same age
n producing the Intelligence Quotient, or IQ.
n
IQ computation is based on a
normal distribution of scores,
n
A pattern of data in which
scores fall symmetrically around a mean value, with most scores falling close
to the mean and fewer scores at the high and low ends.
Infant Intelligence Tests
Most measure perceptual and motor responses
Bayley Scale of Infant Development
But, poor predictors of later intelligence. WHY?
Best intelligence predictor from infancy?
Habituation procedure
Bornstein & Sigman (1986): median predictive correlation = 0.47.
Infants tested at 4 to 7 months and retested later (IQ, vocab, reading): Correlation: 0.42.
Infant habituation predicts vocabulary size at 1 and IQ at 4.
Note:
What and How Well Do Intelligence Tests Predict?
Stability of IQ scores
There are two generalizations about stability:
The older the child at first testing:
2-5=.32 5-8=.70 9-12=.85
The closer in time the two tests:
4-5=.72 4-6=.62 4-18=.42
• Before 5-6, IQ measures present ability, not a stable measure.
Why?
Stability of Absolute Scores
• Longitudinal research: from childhood to adolescence IQ fluctuates 10-20 points
Gainers:
Decliners:
IQ as predictor of scholastic performance
Intelligence tests DO predict academic achievement:
Correlations from .40 to .70. Most around .50.
Why?
Is it genes or experience?
IQ-achievement correlation higher in identical than fraternal twins.
Note: motivation and personality also important.
IQ as predictor of occupational attainment/performance
2nd grade: high IQ predicts becoming lawyer, scientist, etc.
IQ also correlates with on-the-job performance
But: other variables important: “need to achieve”, family background
Racial & Socioeconomic Differences in IQ
A very controversial issue. The outcomes predicted by IQ vary by race/ethnicity/SES.
•
• Low SES children score less than middle SES children.
•
Asian-American scores are higher than those of any other group in the
Are early differences genetic? Or
fewer opportunities for some racial/ethnic groups?
Does SES account for racial discrepancy? Yes and no.
• If matched for SES,
But: individual differences: curves overlap
Jenson (1969, 1973, 1980): Level I-Level II theory
Level I = rote learning
Level II = complex cognitive processing.
• Claimed differences due to Level II not Level I.
But, what about culturally loaded
questions?
Jenson: black children do worst on least culturally loaded questions –
But: when black children grow up in a white middle-class home?
They attain IQ scores 20 points above mean of black children in low SES communities
Interventions
l
Many
home- and center-based intervention programs were initiated in the 1960s to
enhance the intellectual development of poor children
¡
In a
comprehensive analysis of eleven early-intervention programs, Lazar found that
initial IQ gains were lost over time
¡
However,
program participation was linked to and special-education placement, higher rates
of high
school graduation, and higher earnings as adults
Project Head Start
l
Has
provided a range of services to more than 13 million children for 35 years
l
At
present, serves about 1 million 3- to 5-year-olds each year in approximately
2,000 centers around the
¡
Children
receive medical, dental, and nutrition services as well as intellectual
stimulation and day care
¡
Emphasizes
involving family and community; building on children’s strengths; and fostering
social, emotional and physical as well as intellectual growth
¡
Long-term
results are consistent with those of other early intervention programs
Does Schooling Influence IQ?
Intelligence affects achievement: does schooling affect intelligence?\
Ceci (1990, 1991): Meta-analysis of 100’s of studies.
Suggests that events in classroom have profound effects:
Summer:
• IQ over summer, especially low income children.
• Advantaged children in summer activity show
What other features of schooling?
Irregular attendance: has larger impact on IQ.
Regular schooling gives point advantage.
Delayed entry: loss per year delayed schooling.
Drop out: each year not completed loses 1.8 points.
Ceci (1991) claims schooling influences IQ in three ways:
Beyond IQ: The Development of Creativity
Creativity is often ignored in IQ tests. Why?
• People who are a “genius” are often highly creative.
Creativity in children: convergent and divergent thinking.
Convergent thinking:
Divergent thinking:
IQ and divergent thinking poorly correlated: in intelligent adults is virtually zero.
Nature versus nurture?
Creative children’s parents:
School doesn’t help: answer-centered approach stops unusual ideas.
Is early divergent thinking correlated with later
creativity?
Inconsistent evidence.
• Perhaps a better indicator of creative talent is specialized talent.
Many now focus on
• Genes important to this talent: but needs instruction, guidance.