I. What is intelligence?
II. How is it tested?
III. Controversies
Part I: Intelligence
Intelligence
• Intelligence should be universal
• Exactly how intelligence is expressed
will differ given the context.
History of Intelligence Testing
History of Intelligence Testing
• (1600s) Francis Bacon - the scientific method
History of Intelligence Testing
• (1600s) Francis Bacon - the scientific method
• (1800s) Francis March “vulgar utilitarianism”
History of Intelligence Testing
• (1600s) Francis Bacon - the scientific method
• (1800s) Francis March “vulgar utilitarianism”
• Francis March sat beside James Cattell
History of Intelligence Testing
• James Cattell gets stoned, and then argues
History of Intelligence Testing
• James Cattell gets stoned, and then argues
• Cattell becomes a psychometrician
History of Intelligence Testing
• James Cattell gets stoned, and then argues
• Cattell becomes a psychometrician
• At Cambridge falls in with Francis Galton
History of Intelligence Testing
• James Cattell gets stoned, and then argues
• Cattell becomes a psychometrician
• At Cambridge falls in with Francis Galton
• Francis Galton would later develop eugenics
History of Intelligence Testing
• James Cattell gets stoned, and then argues
• Cattell becomes a psychometrician
• At Cambridge falls in with Francis Galton
• Francis Galton would later develop eugenics
• 1889 - Cattell is now a professor at age 29
History of Intelligence Testing
• Cattell coined ‘mental tests’
• For example,
– Bisection of a 50 cm line
– Judgment of a 10 second time
– Number of letters repeated
History of Intelligence Testing
• 1895 Cattell moves to Columbia U (NY)
History of Intelligence Testing
• 1895 Cattell moves to Columbia U (NY)
• As president of the APA Cattell convenes a
meeting
History of Intelligence Testing
• 1895 Cattell moves to Columbia U (NY)
• As president of the APA Cattell convenes a
meeting
• recommends they test
a) senses,
b) motor capacity, and
c) mental processes
History of Intelligence Testing
• 1895 Cattell moves to Columbia U (NY)
• As president of the APA Cattell convenes a
meeting
• recommends they test
a) senses,
b) motor capacity, and
c) mental processes
• Back in France Binet emerges on the scene
History of Intelligence Testing
• Spearman gives birth to the g/s factor theory
History of Intelligence Testing
• Henry Goddard emerges, and in 1908 visits
Binet
History of Intelligence Testing
• Binet’s ideas of testing move away from labels
History of Intelligence Testing
• Binet’s ideas of testing move away from labels
• IQ = (Mental age/chronological age) *100
• For example, (15/10) * 100 = 150
History of Intelligence Testing
• Binet’s ideas of testing move away from labels
• IQ = (Mental age/chronological age) *100
• For example, (15/10) * 100 = 150
• Ellis Island under Goddard
• WWI recruits under Yerkes & Terman
History of Intelligence Testing
• 1920s -remember Cattell studied with
Darwin’s cousin Galton
History of Intelligence Testing
• 1920s -remember Cattell studied with
Darwin’s cousin Galton
• Terman argued that the correlation between
test scores and social status pointed to
heredity of intelligence
History of Intelligence Testing
• 1920s -remember Cattell studied with
Darwin’s cousin Galton
• Terman argued that the correlation between
test scores and social status pointed to
heredity of intelligence
• Terman would work with Thorndike
• Dewey argues that these tests measure a
social construction
History Leads to Theory
• Thurstone’s work would lead to the
recognition that there are 7-9 mental abilities
History Leads to Theory
• Horn, student of Cattell, brings together work
in the field and devises the
Cattell-Horn Theory
History Leads to Theory
• Horn, student of Cattell, brings together work
in the field and devises the
Cattell-Horn Theory
• Modern theory rests on the idea that
intelligence can be found by analyzing intercorrelations of scores on mental ability tests
History Leads to Theory
• Meanwhile distinct factor analytic work by
Carroll has led to
General
(Stratum III)
Broad
(Stratum II)
Narrow
(Stratum I)
CARROLL’S (1993) THREE-STRATUM
THEORY OF COGNITIVE ABILITIES
g
General
Intelligence
Gf
Fluid
Intelligence
Gc
Crystallized
Intelligence
(Carroll, 1993, 1997)
Gy
General
Memory &
Learning
Gv
Broad
Visual
Perception
Gu
Broad
Auditory
Perception
Gr
Broad
Retrieval
Ability
Gs
Broad
Cognitive
Speediness
69+ narrow abilities found in data sets analyzed by Carroll
Gt
Processing
Speed (RT
Decision
Speed)
Intelligence Theory Meets Practice
• 1985 Richard Woodcock hears about the
theory
• 1989 The Great Gathering
• This leads to factor analytic studies of the WJ
Gardner’s Multiple Intelligences
1.
2.
3.
4.
5.
6.
7.
8.
Linguistic
Logical-mathematical
Spatial
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
Naturalist
Part II: Testing Intelligence
Individual Tests of Intelligence
•
•
•
•
Stanford-Binet
Wechsler Scales
Kaufman Scales
Woodcock Johnson
Wechsler Scales
• Wechsler Adult Intelligence Scale
– WAIS, WAIS-R, WAIS-III
• Wechsler Intelligence Scale for Children
– WISC, WISC-R, WISC-III, WISC-IV
• Wechsler Preschool and Primary Scale of
Intelligence (WPPSI)
Subscales of the WISC-III
Verbal
Performance
Information
Picture Completion
Similarities
Picture Arrangement
Arithmetic
Symbol Search
Vocabulary
Object Assembly
Comprehension
Coding
Digit Span
Mazes
Part III: Controversies
Testing Issues
• Inadequate sample of each domain
• Limited (nonspecific) treatment or instruction
implications
Binet
Wechsler
Terman
Gardner
Thurstone
Yerkes
Cattell
Horn
Bell Curve Assertions
• IQ tests are not biased against minority groups.
• A significant fraction of the individual differences in
IQ scores is explained by genetics (40-60%).
• African-Americans score significantly lower than
White-Americans on IQ tests (12-15 points).
Gould Debunks the Bell Curve
• “The authors omit facts, misuse statistical
methods, and seem unwilling to admit the
consequences of their own words.”
• “Nothing . . . angered me more than the
authors’ failure to supply any justification for
their central claim . . . that the number known
as g . . . captures a real property in the head.”
Bigger Questions
• Are intelligence tests useful? If so, for what? If
not, why not?
• Are intelligence tests biased?
• What are the positive and negative social
consequences of using intelligence tests?
• What are the alternatives?
APA Consensus Statement
• It is widely agreed that standardized tests do
not sample all forms of intelligence.
• Environmental factors contribute substantially
to the development of intelligence, but it is
not clearly understood what those factors are
or how they work.
The Flynn Effect
• Across 14 nations, 5-25 point increase in IQ
within one generation
• 90% of those born 100 years ago would score
at the 5th percentile of current norms
• Are we really getting smarter?