devt’l handouts, Ch. 9- intelligence
1
Intelligence


Adaptive thinking or action (Piaget)
Ability to think abstractly, to solve problems (Sternberg)
Psychometric Views
Intelligence: a trait/set of traits that characterises some people more than others.
 Binet: intelligence develops with age; age-graded test
 Factor analytic perspective: a single score is not adequate.
- Spearman (1927): underlying general mental factor, “g”; special
abilities, “s”
- Thurstone (1938; 1941): 7 Primary Mental Abilities
1. spatial ability
2. perceptual speed
3. numerical reasoning
4. verbal meaning
5. word fluency
6. memory
7. inductive reasoning
- Guilford (1967; 1988): more than 100 distinct mental abilities
-
Cattell & Horn (1963; 1982; 1992):
*fluid: novel and abstract problems free of cultural influence;
levels off in adulthood, declines with age
*crystallized: problems that depend on acquired knowledge;
increases with age
Information-Processing View:
 Sternberg (1985; 1991): Triarchic Theory:
* Context: intelligent people adapt to their environment
* Experience: response to novelty; automatized routines for everyday tasks
* Information Processing Skills: focus on how we learn, not what we know
Gardner’s (1983) Multiple Intelligences:
(at least) 7 distinct kinds of intelligence:
1. linguistic
2. spatial
3. logical-mathematical
4. musical
5. body-kinesthetic
6. interpersonal
7. intrapersonal
Each is linked to a specific brain area.
devt’l handouts, Ch. 9- intelligence
2
brain injury; “idiot savants”
7 areas are not independent; current IQ tests find them
moderately correlated.
-----------------------------------------------------------------------------------------------------------Support:
Criticisms:
Measuring Intelligence

Stanford-Binet Intelligence Scale
- age-graded tasks for 3-13 yr olds
- ratio measure, or Intelligence Quotient
IQ =

mental age
chronological age
X 100
revised with current norms for ages 2 to 18
measures
verbal reasoning; quantitative reasoning; spatial
reasoning; short-term memory
new version uses deviation IQ
Wechsler Scales
- WISC-III (Wechsler Intelligence Scale for Children) ages 6-16
- WPPSI-R (Wechsler Pre-school and Primary Scale of Intelligence)
ages 3 to 8
- Verbal items: vocabulary, general knowledge, ideas and concepts,
arithmetic reasoning
- Performance items: puzzles, mazes, block design, picture arrangement
- 2 scores: Verbal IQ and Performance IQ
Distribution of IQ Scores
Mean = 100, s.d. = 15
+1 s.d.
+2 s.d.
-1 s.d.
-2 s.d.
= IQ of 115; 84th %ile
= IQ of 130; 98th %ile
= IQ of 85; 16th %ile
= IQ of 70; 2nd %ile
Infant Intelligence:
 Bayley Scales of Infant Development
- motor scale
- mental scale
- infant behavioural record
- yields a DQ
Baby’s speed of habituation and preference for novelty predict IQ in grade school
years, r = .45.
devt’l handouts, Ch. 9- intelligence
3
Is IQ stable?
- fluctuates on average 28.5 points from 2 ½ to 17
- especially true of unstable family environments
IQ Tests Predict:
 current academic success, r = .50
 future academic success, r as high as .73 (gr 4 to 6)
 higher IQ: better jobs; better job performance (r = .50)
 in childhood higher IQ predicts better health; moral maturity; leadership;
social & psychological adjustment
 as adults, gifted children will have lower incidences of alcoholism, poor
health, psychiatric problems, delinquency. Better marriages.
-----------------------------------------------------------------------------------------------------------Factors Influencing IQ Scores:



Heredity: Twin studies, Adoption studies
Impoverished Environment:
- Klineberg’s (1963) cumulative deficit hypothesis
- Hensen (1977) older siblings in impoverished environments have lower
IQs
Enriched Environment:
- improved environment: IQs increased 11 points
- adoption studies

Samenoff et al (1993): risk factors for poor IQ test scores:
- minority group
- unemployed head of house
- mother poor education
- 4+ children in family
- absent father
- stressful family events
- rigid child-rearing
- anxious/distressed mother
- mother poor mental health
- mother has little + affect for child

Birth Order, Family Size:
- brighter kids  smaller families
- first born > second born > third born, etc.
devt’l handouts, Ch. 9- intelligence

Social Class, Race, Ethnicity:
- lower s.e.s
- non-white children
4
 IQ 10-15 points lower
 12 – 15 points lower
1) test bias hypothesis – but tests are much more culture-fair now.
2) genetic hypothesis
Jensen (1980):
level 1 abilities 
level 2 abilities 
attention, stm
abstract reasoning, symbolic
manipulation
- tested in IQ tests
- white children do better
- genetic
Critique: no evidence that group differences in IQ are genetically determined!
3) environmental hypothesis: lower scores come from groups in impoverished
environments
- poorer homes: poor nutrition, psychological stress, parents poorly
educated
- adoption research
* Scarr & Weinberg (1983; 1992): inter-racial kids raised in white middle class
homes had higher IQs than interracial kids in disadvantaged interracial
households.