Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
Module 13
Intelligence
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DEFINING INTELLIGENCE
• Two-factor theory
– Psychometric approach
• measures or quantifies cognitive abilities or
factors that are thought to be involved in
intellectual performance
– Two-factor theory,
• by Charles Spearman
• says that intelligence has two factors:
• general mental ability factor “g”
• represents what different cognitive tasks have
in common
• specific factors which include specific mental
abilities such as mathematical, mechanical, or
verbal skills “s”
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DEFINING INTELLIGENCE (CONT.)
• Multiple-intelligence theory
– Gardner’s multiple-intelligence theory
• Howard Gardner
• instead of one kind of general intelligence,
there are at least seven different kinds which
include:
• verbal intelligence
• musical intelligence
• logical mathematical intelligence
• spatial intelligence
• body movement intelligence (to understand
oneself)
• intelligence to understand others
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DEFINING INTELLIGENCE (CONT.)
• Triarchic theory
– Robert Sternberg
• says that intelligence can be divided into three
different kinds of reasoning processes
1. uses analytical or logical thinking skills that
are measured by traditional intelligence
tests
2. uses problem-solving skills that require
creative thinking and the ability to learn
form experience
3. uses practical thinking skills that help a
person adjust to, and cope with, his or her
sociocultural environment
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INELLIGENCE
• Earlier attempts to measure intelligence
– head size and intelligence
• Francis Galton
– noticed that intelligent people often had intelligent
relatives and concluded that intelligence was, to a
large extent, biological or inherited
– low correlation between head size and
intelligence
– using head size as a measure of intelligence was
abandoned in favor of using skull or brain size
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
p284 BRAIN SIZE
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INELLIGENCE
• Earlier attempts to measure intelligence
– Brain size and intelligence
• Paul Broca
• claimed there was a relationship between size
of brain and intelligence
• larger brains indicating more intelligence
• later reanalysis of Broca’s data indicted that
measures of brain size proved to be unreliable
and poorly correlated with intelligence
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Earlier attempts to measure intelligence
– brain size and achievement
– enormous variation in brain size and achievement
– brain size, sex differences, and intelligence
– women’s brains weigh about 10% less than men’s
– little or no difference in intelligence between men
and women
– larger size of men’s brains does not result in
higher IQs
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Binet’s breakthrough
– Alfred Binet
• believed that intelligence was a collection of
mental abilities and that the best way to
assess intelligence was to measure a person’s
ability to perform cognitive tasks, such as
understanding the meanings of words or being
able to follow directions
• Binet-Simon Intelligence Scale
• contained items arranged in order of
increasing difficulty
• measured vocabulary, memory, common
knowledge, and other cognitive abilities
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Binet’s breakthrough
– mental age: measure of intelligence
– Binet and Simon revised their intelligence scale to
solve several problems in their original scale
– mental age
– method of estimating a child’s intellectual
progeress by comparing the child’s score on an
intelligence test to the scores of average children
of the same age
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Formula for IQ
– Intelligence quotient
• computed by dividing a child’s mental age
(MA), as measured in an intelligence test, by
the child’s chronological age (CA) and
multiplying the result by 100
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
p285 FORMULA FOR IQ
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Wechsler Intelligence Scale
– most widely used IQ tests
– Wechsler Adult Intelligence Scale (WAIS-III), ages
16 and older
– Wechsler Intelligence Scale for Children (WISCIII) for children ages 3-16
– both have items that are organized into various
subtests.
– verbal section
– performance section
– verbal and performance combined give a single
IQ
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
MEASURING INTELLIGENCE (CONT.)
• Two characteristics of tests
– Validity
• means that the test measures what it is
supposed to measure
– Reliability
• refers to consistency: score on a test at one
point in time should be similar to the score
obtained by the same person on a similar test
at a later point in time
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DISTRIBUTION & USE OF IQ SCORES
• Normal distribution of IQ scores
– Normal distribution
• refers to a statistical arrangement of scores so
that they resemble the shape of a bell and,
thus, is said to be a bell-shaped curve
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
p288 IQ CHART
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DISTRIBUTION & USE OF IQ SCORES (CONT.)
• Mental retardation: IQ scores
– Mental retardation
• refers to a substantial limitation in present
functioning that is characterized by significantly
subaverage intellectual functioning, along with
related limitations in two of ten areas, including
communication, self-care, home living, social
skills, and safety.
• borderline mentally retarded: IQs from 50 to
75
• mildly/moderately mentally retarded: IQs from
35 to 50
• severely/profound mentally retarded: IQs from
20 to 40
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DISTRIBUTION & USE OF IQ SCORES (CONT.)
• Mental retardation: IQ scores
– Causes
• Organic retardation
– results from genetic problems or brain
damage
• Cultural-familial retardation
– results from a greatly impoverished
environment.
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
DISTRIBUTION & USE OF IQ SCORES (CONT.)
• Vast majority: IQ scores
– about 95%, have scores that fall between 70 and
130
• Gifted: IQ scores
• Moderately gifted
– usually defined by an IQ score between
130 and 150
• Profoundly gifted
– usually defined by an IQ score around 180
or above
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
NATURE-NURTURE QUESTION
• Definitions
– asks how nature-hereditary or genetic factorsinteracts with nurture-environmental factors-in the
development of a person’s intellectual, emotional,
personal, and social abilities
• Twin studies
– Fraternal twins
• like siblings (brothers and sisters), develop
from separate eggs and 50% of their genes in
common
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
NATURE-NURTURE QUESTION (CONT.)
• Twin studies
– Identical twins
• develop from a single egg and thus have
identical genes, which means that they have
100% of their genes in common
– Interaction of nature and nurture
• when researchers report that genetic factors
influence intelligence (IQ scores)
• mean that genetic factors influence cognitive
abilities to varying degrees, depending on the
environment
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
NATURE-NURTURE QUESTION (CONT.)
• Adoption studies
– children with limited social-educational
opportunities and low IQs were adopted by
parents who could provide increased socialeducational opportunities
– studies show that children with poor educational
opportunities and low IQ scores can show an
increase in IQ scores when they are adopted into
families that provide increased educational
opportunities
Introduction to Psychology, 7th Edition, Rod Plotnik
Module 13: Intelligence
NATURE-NURTURE QUESTION (CONT.)
• Interaction: nature and nurture
– Heritability
• number that indicates the amount or proportion
of some ability, characteristic, or trait that can
be attributed to genetic factors (nature)
– Reaction range
• indicates the extent to which traits, abilities, or
IQ scores may increase or decrease as a
result of interaction with environmental factors