Chapter 10
Intelligence
© 2013 Worth Publishers
Chapter
Overview
Overall question to consider:
does each of us have an inborn level of
talent, a general mental capacity or set of
abilities, and can that level be measured and
represented by a score on a test?
 Definitions of intelligence
 One ability or many?
 The role of creativity and emotional intelligence
 How to construct tests to try to assess intelligence
 Intelligence stability, change, and extremes
 Genetic vs. environmental influences
 Group differences in ability
 Racial difference or cultural test bias?
“Definition” of Intelligence
 Intelligence tests are a series
of questions and other
exercises which attempt to
assess people’s mental abilities
in a way that generates a
numerical score, so that one
person can be compared to
another.
 Intelligence can be defined as
“whatever intelligence tests
measure.”
 Your college entrance test
measures how good you are
at scoring well on that test.
Definition of Intelligence:
Beyond the Test?
The text defines
intelligence,
whether it’s math
ability or a rainforest
dweller’s
understanding of
plants, as the ability
to learn from
experience, solve
problems, and use
knowledge to adapt
to new situations.
Intelligence: Single or Multiple?
Is intelligence one general ability or several specific
abilities?
Charles Spearman
general intelligence [g]
Louis Thurstone
7 linked clusters of abilities
Howard Gardner
8 intelligences
Robert Sternberg
3 intelligences
Creativity and intelligence 5 components
Emotional intelligence
4 components
General Intelligence,
also known as g
Charles Spearman (1863-1945) performed a factor analysis* of
different skills and found that people who did well in one area
also did well in another. Spearman speculated that these people
had a high “g” (general intelligence).
*Factor analysis refers to a statistical technique that determines
how different variables relate to each other; for example
whether they form clusters that tend to vary together.
Thurstone’s Seven Clusters of Abilities
 Louis Thurstone (18871955) disagreed with
the idea of one general
measure and trait of
overall intelligence.
 Thurstone found that
the results of 56 skill
tests fell into 7 clusters.
 However, further
analysis showed that
people who were
strong in one cluster
tended to be strong in
other clusters.
1. Verbal
comprehension
2. Inductive
reasoning
3. Word fluency
4. Spatial ability
5. Memory
6. Perceptual
speed
7. Numerical
ability
g
Multiple Intelligences
The “savant syndrome” refers to having
isolated “islands” of high ability amidst a
sea of below-average cognitive and social
functioning.
Howard Gardner’s Multiple Intelligences
 Howard Gardner (b. 1943) noted that different people
have intelligence/ability in different areas.
 Research and factor analysis suggests that there may be
a correlation among these intelligences.
Howard Gardner’s Eight Intelligences
Intelligence and Success
“Success in life” is
impossible to define.
However, wealth tends to
be related to intelligence
test scores, PLUS:
 focused daily
effort/practice, taking
10 years to achieve
success-level expertise.
 social support and
connections.
 hard work and
energetic persistence
(grit).
10
Sternberg’s Intelligence Triarchy
Robert Sternberg (b. 1949) proposed that “success” in
life is related to three types of ability.
Analytical
intelligence:
Practical
intelligence:
expertise and
talent that help to
complete the
tasks and manage
the complex
challenges of
everyday life
solving a welldefined problem
with a single
answer
Creative
intelligence:
generating new
ideas to help
adapt to novel
situations
Creativity
Creativity refers to the ability to
produce ideas that are novel and
valuable.
[Creative intelligence involves
using those ideas to adapt to
novel situations.]
Convergent thinking is a
left-brain activity involving
zeroing in on a single correct
answer.
Creativity uses divergent
thinking, the ability to
generate new ideas, new
actions, and multiple options
and answers.
Does chess involve creativity?
Robert Sternberg’s Five
Components of Creativity
Creative environment: having
support, feedback, encouragement,
and time and space to think
Venturesome personality:
tending to seek out new
experiences despite risk,
ambiguity, and obstacles
Expertise:
possessing a welldeveloped base of
knowledge
Intrinsic motivation:
enjoying the pursuit of
interests and challenge,
without needing external
direction or rewards
Imaginative thinking: having
the ability to see new
perspectives, combinations,
and connections
To Boost Creativity:
Four Strategies
 Pursue an interest until you
develop expertise.
 Allow time for incubation
(“sleeping on it”) with your
attention away from projects,
during which unconscious
connections can form.
 Allow time for mental
wandering and aimless
daydreaming with no
distractions.
 Improve mental flexibility by
experiencing other cultures
and ways of thinking.
Social and Emotional Intelligence
Social intelligence
refers to the ability
to understand and
navigate social
situations.
Emotional
intelligence
involves processing
and managing the
emotional
component of those
social situations,
including one’s own
emotions.
Components of
Emotional Intelligence
Perceiving emotions
•Recognizing emotions in facial
expressions, stories, and even in music
Understanding emotions
•Being able to see blended emotions,
and to predict emotional states and
changes in self and others
Managing emotions
•Modulating and expressing emotions in
various situations
Using emotions
•Using emotions as fuel and motivation
for creative, adaptive thinking
Benefits of
Emotional Intelligence
People with high
emotional intelligence
often have other
beneficial traits, such as
the ability to delay
gratification while
pursuing long-term
goals.
The level of emotional
intelligence, including
the skill of reading the
emotions of others,
correlates with success
in career and other
social situations.
Intelligence and Brain Anatomy
“Genius” seems to correlate
with:
 overall brain size.
 the size of some brain
regions such as the parietal
lobe.
 high brain activity in the
frontal and parietal lobes.
 extra gray matter (brain cell
bodies, seen as more brain
surface area/convolutions).
 extra white matter (axons)
leading to high connectivity
among different regions.
Intelligence and
Brain Functioning
Intelligence in action seems
to involve:
•activity of the front part
of the frontal lobes to
organize and coordinate
information
•“being in shape”; using
less energy to solve
problems than the
brains of “normal”
people.
Intelligence and Processing Speed
Verbal and general intelligence test scores correlate
with the:
 speed of retrieving information from memory.
 speed of receiving and processing sensory and
perceptual information.
Q: Did you process
the tic tac toe
game deeply
enough to say
whether it was
an X or an O in
each of the
now-empty
squares?
Assessing Intelligence
Assessment refers
to the activity and
Why Try to Measure Intelligence?
the instruments
 to study how (and why) people
used to measure
differ in ability
intelligence.
The challenge is to
 to match strengths and weaknesses
make these
to jobs and school programs
instruments valid
 to help the “survival of the fittest”
(measure what they
process; trying to select the people
are supposed to
who have the greatest abilities.
measure) and
This was the position of eugenicist
reliable (yielding
the same score if
Francis Galton (1822-1911).
administered again,
even if
administered by
someone else).
Predicting School Achievement:
Alfred Binet
 Problem: in the late 1800s,
a new law in France
required universal
education even for those
without the ability to
succeed with the current
instruction.
 Solution: Alfred Binet
devised tests for children
to determine which ones
needed help.
 Binet hoped to predict a
child’s level of success in
regular education.
Intelligence: Growing
with Age?
 Alfred Binet assumed that all children follow the same
course of development, some going more quickly, and
others more slowly.
 Binet’s tests attempted to measure mental age--how far
the child had come along on the “normal” developmental
pathway.
 The implication was that children with lower ability were
delayed (with a mental age below their chronological
age), and not disabled; with help, they could improve.
Binet  Stanford-Binet
 Lewis Terman, of Stanford
University, adapted
Alfred Binet’s test, adding
new test items and
extending the age range
into adulthood.
 Terman also tested many
California residents to
develop new norms, that
is, new information about
how people typically
performed on the test.
 The result was the
Stanford-Binet
intelligence test.
William Stern’s scoring (1914) of
the Stanford-Binet test resulted
in the concept of IQ, the
Intelligence Quotient.
Binet reported scores as simply
one’s mental age; a 10 year old
with below average intelligence
might have a mental age of 8.
William Stern preserved Binet’s
comparison of mental to
chronological age as:
ratio/quotient.
Q: What IQ score do we get for
What do scores
mean?
What to do if you score
low on an IQ test?
 Lewis Terman, of
Stanford University,
began with a
different assumption
than Binet; Terman
felt that intelligence
was unchanging and
innate (genetic).
Binet
 Later, Terman saw
how scores can be
affected by people’s
level of education
Remove your
and their familiarity genes from the
population
with the language
(eugenics).
and culture used in
the test.
Study, and
develop selfdiscipline and
attention span.
Terman
Aptitude vs. Achievement
 Achievement tests measure what you already have learned.
Examples include a literacy test, a driver’s license exam, and a final
exam in a psychology course.
 Aptitude tests attempt to predict your ability to learn new skills.
 The SAT, ACT, and GRE are supposed to predict your ability to do
well in future academic work.
If the SAT is an
aptitude test,
should it
correlate with
IQ?
IQ
SAT scores (verbal + quantitative)
David Wechsler’s Tests:
Intelligence PLUS
The Wechsler Adult
Intelligence Scale
(WAIS) and the
Wechsler Intelligence
Scale for Children
(WISC) measure “g”/IQ
and have subscores for:
verbal comprehension.
processing speed.
perceptual organization.
working memory.
Principles of Test Construction
In order for intelligence or other psychological
tests to generate results that are considered
useful, the tests (and their scores) must be:
standardized.
reliable.
valid.
Standardization
Many intelligence tests generate a raw score based on the
number of answers correct, but can we turn this into a
number that tells us how smart/capable a person is
compared to the general population?
Standardization means defining the
meaning of scores based on a comparison
with the performance of others who have
taken the test before.
William Stern compared our intelligence test score to
others by finding a “mental age” of people who scored on
average the way we did.
A newer method of generating an intelligence test score is
to determine where your raw score falls on a distribution of
scores by people of your chronological age.
Standardization:
How “Normal” is Your Score?
 Number of people with this score 
If we stacked a bunch of Weschler Intelligence Tests (by people
your age) in a pile placed by raw score (number of test items
correct), there would be a few very high scores and a few low
scores, and a big pile in the middle; this bell-shaped pile is called
the normal curve. We will call the average raw score “IQ 100.”
Comparing your score
to this standard set of
scores: if you score
higher than 50
percent of people,
you your IQ is 100.
If your score is
higher than 98
percent of the
population, your
IQ is around what
number?
Re-Standardization
and the Flynn Effect
Re-Standardization: Re-testing a sample of the general
population to make an updated, accurate comparison group,
in case people are smarter than they used to be when the
test was first made.
The Flynn Effect:
Performance on
intelligence tests
has improved over
the years,
worldwide.
Test your understanding
You took an intelligence test last week and
were assigned a number of 120. Then, after
decades of the Flynn effect, the test was
restandardized this week. Today, you took the
same test and got exactly the same number
of items correct. Your new intelligence test
score is most likely to be:
A. 105
B. 120
C. 128
Reliability and Validity
A test or other measuring
tool is reliable when it
generates consistent results.


Split-half reliability: do
two halves of the test
yield the same results?
Test-retest reliability:
will the test give the
same result if used
again?
If your height was
measured with a ruler
made of stretchy material,
what would be the
problem?
A test or measure has validity
if it accurately measures
what it is supposed to
measure.
 Content validity: the test
correlates well with the
relevant criterion, trait,
or behavior
 Predictive validity: the
test predicts future
performance (e.g. an
aptitude test relates to
future grades)
If your height was measured
with a yardstick on which the
units were too small, what
would be the problem?
Predictive
Validity: Only
in Broad
Ranges
At the higher range of
weights and success, weight
is less of a valid predictor of
success of football linemen.
Dynamics of
Intelligence
Are intelligence test
scores stable or do
they change with
age?
Stability of Intelligence during Aging
Evidence for
change/decline
Evidence for
stability
Cross-sectional studies
examine people of different
ages all at once.
Older adults do not perform
as well as younger adults on
intelligence tests.
 What factors could explain
this?
 What is different about
these different
populations other than
their chronological age?
Longitudinal studies track the
performance of one group of
people, or cohort, over time.
This method yields evidence
that intelligence remains
stable, or even increases, over
time.
 What could account for
this result?
 What are the shortcomings
of this method?
Stability of
Intelligence
during Aging
Putting the evidence
together
Can we combine the
information on this chart
and form a general
impression about
whether intelligence
declines with age?
Stability of Intelligence
during Aging:
Which type of intelligence?
Based on this chart,
at what age might
you do best at
completing a
crossword puzzle
quickly?
Fluid and Crystallized Intelligence
Fluid intelligence refers to
the ability to think quickly
and abstractly.
Crystallized intelligence
refers to accumulated
wisdom, knowledge,
expertise, and vocabulary
.
Stability of Intelligence Test Scores
Over the Lifespan
Pushing toddlers to learn does not seem to help much. Only
by age four is a child’s performance on intelligence tests a
predictor of future performance on intelligence tests.
Based on the
results of a
longitudinal study
depicted in this
chart, does
intelligence test
score at age 11
predict
intelligence test
score at age 80?
Intelligence and Longevity
In a Scottish longitudinal study, 11-year-olds with higher
intelligence test scores lived longer and more independently
and were less likely to develop Alzheimer’s Disease.
In a study of nuns ,
those with lower
verbal ability were
later more likely to
develop Alzheimer’s
Disease, which
includes a shorter
lifespan.
Extremes of Intelligence
The Wechsler Intelligence Scale is set so that about 2
percent of the population is above 130 and about 2 percent
of the population is below 70.
Intellectual
Disability
Very High
Intelligence,
Gifted
Extremes of
Intelligence
“Intellectual disability” refers to people who
 have an IQ around 70 or below.
 have difficulty with adaptive skills, such as:
 conceptual skills (literacy and
calculation).
 social skills, including making safe social
choices.
 practical daily living skills such as
hygiene, occupational skills, and using
transportation.
 Although some people with high intelligence
test scores can seem socially delayed or
withdrawn, most are “successful.”
 “Gifted” children, like any children, learn
best with an appropriate level of challenge.
 Segregated, “tracked” programs, however,
often unfairly widen achievement gaps.
Genetic and Environmental
Influences on Intelligence
(Nature and Nurture)
 Even if we agree for argument’s sake that “success” in
life is caused in part by some kind of intelligence, there is
still a debate over the origin of that intelligence.
– Are people “successful” because of inborn talents?
– Or are they “successful” because of their unequal
access to better nurture?
 Information to tease out the answers can be found in
some twin and adoption studies.
Genetic and Environmental Influences on Intelligence
Studies of Twins Raised Apart
What explains this difference?
What explains this difference?
Findings from
these studies
indicate that
both nature
and nurture
affect
intelligence
test scores.
Clarifying Heritability
Heritability
 If three people had exactly
the same education,
 When you see variation
nutrition, and experiences,
in intelligence between
some psychologists speculate
two or more people, the
that genes might be
heritability of that trait
responsible for perhaps 40
is the amount of
percent of their intelligence;
variation that is
nurture certainly made a big
apparently explained by
impact.
genetic factors.
 However, such identical
 This does NOT tell us the
nurturing (which is actually
proportion that genes
impossible) could not create
contribute to the trait for
differences in intelligence.
any one person.
 With identical nurture, the
heritability of intelligence
would be virtually 100
percent.
Genetic Influences on Intelligence
 Identical twins seem to show
similarity in specific talents
such as music, math and
sports.
 The brains of twins show
similar structure and
functioning.
 There are specific genes
which may have a small
influence on ability.
Adoption Studies
With age, the intelligence test scores of adoptees looks
more and more like that of their ____________ parents.
(adoptive? birth/biological?)
In another study,
heritability of
intelligence test
scores continued
to increase
beyond age 16.
Environmental
Influences on
Intelligence
 Environment has more
influence on intelligence
under extreme
conditions such as
abuse, neglect, or
extreme poverty.
 Tutored human
enrichment has a larger
impact on compensating
for deprivation than on
boosting intelligence
under normal
conditions.
Schooling and Intelligence
 Preschool and elementary
school clearly have at least a
temporary impact on
intelligence test scores.
 College can have a positive
impact on intelligence test
scores if students have:
– motivation and incentives.
– belief that people can
improve.
– study skills, especially the
willingness to practice.
Understanding Group Differences
in Test Scores
Now, let’s look at:
 gender differences.
 “racial” differences.
 understanding the impact of
environment.
 within-group differences and
between-group differences.
 the impact of test bias and
stereotype threat on
performance.
Supposed Male-Female Ability Differences
Male/female
difference
related to
overall
intelligence
test score.
Boys are more likely than girls to be at the high or low
end of the intelligence test score spectrum.
Male-Female
Ability Differences
 Girls tend to be better at spelling, locating objects,
and detecting emotions.
 Girls tend to be more verbally fluent, and more
sensitive to touch, taste, and color.
 Boys tend to be better at handling spatial reasoning
and complex math problems.
 It is a myth that boys generally do better in math
than girls. Girls do at least as well as boys in overall
math performance and especially in math
computation.
Tests of Male and Female Strengths
Standard
Ethnic/Racial Differences in
Intelligence Test Scores
The bell curve for African American intelligence test scores is
centered at 85. For non-African Americans, the average is 100.
Whatever the cause of this score difference, it is incorrect to
use this information to predict the score of an individual.
The green triangle shows
African-Americans scoring
higher than the average nonAfrican-Americans.
How can we interpret this
group difference in average
intelligence test scores?
We will look at the issue of
test bias and other factors
affecting scores for perceived
minorities.
But first…
Understanding Group Differences:
Within-group vs. Between-group
Group differences, including intelligence test
score differences between so-called “racial
groups,” can be caused by environmental
factors.
Below: the difference between
groups is caused by poor soil
(environment).
The “Racial” Intelligence Test Score Gap
 Racial categories are not distinct
genetically and are unscientific.
 Both “whites” and “blacks” have
higher intelligence test scores
than “whites” of the 1930s.
 “Whites” may have more access
to “fertile soil” for developing
their potential, such as:
 schools and educational
opportunities.
 wealth, nutrition, support,
and educated mentors.
 relative freedom from
discrimination.
Two Problems
Called “Bias”
Are Tests Biased?
Bias 1: In the popular sense of
Test makers must prevent the word, intelligence tests are
“bias” in the popular sense often biased. Often, tests have
questions which rely on
of the word: making it
knowledge of mainstream
easier for one group than
another to score high on a culture. For example, the 2011
SAT writing prompt demanded
test.
students discuss the
Test makers also strive to
prevent the scientific form authenticity of reality television
shows.
of bias: making it easier
Bias 2: Aptitude tests seem to
for one group than for
predict future achievement
another to have their
equally well for various ethnic
abilities accurately
assessed, and their future groups, and for men and
women.
performance predicted.
The Effect of Stereotype Threat
Study result: Blacks/African-Americans scored higher
when tested by Blacks rather than being tested by
Whites. Why?
Study result: Blacks/African-Americans did worse on
intelligence tests when reminded of their racial/ethnic
identification right before the test. Why?
Study result: Women did worse on math tests than men,
except when they are told first that women usually do as
well as men on the test. Why?
The Power of Expectations
 Stereotype threat refers to a
feeling that one will be
evaluated based on a negative
stereotype.
 Stereotype threat may interfere
with performance by making
people use their working
memory for worrying instead of
thinking.
 This worry is selfconfirming/fulfilling: the effect
of minority status on
performance is worsened by
worry about that effect.
Issues Related to Intelligence Tests
Is discriminating among college or job applicants based
on test scores better than discriminating based on
appearance?
Can test scores be used as Alfred Binet suggested: to
identify those who would benefit from educational
interventions?
Can a person’s worth and potential be summed up in
one intelligence test score?