Chapter 9
Intelligence:
Measuring Mental Performance
WHAT IS INTELLIGENCE?
• Psychometric Views of Intelligence
– Intelligence is a trait (or set of traits) that
allows some people to think and solve
problems more effectively than others
– Binet’s Singular Component Approach
• Developed first intelligence test
• Age graded items produced mental age
• Intelligence is a general mental ability
WHAT IS INTELLIGENCE?
– The Multicomponent View of Intelligence
• Using factor analysis, not a single trait
–Early multicomponent theories
»Spearman; g = general mental;
s = special ability
»Thurstone; 7 primary mental
abilities
•
Figure 9.1 Items similar but not identical to those appearing on intelligence tests for children.
WHAT IS INTELLIGENCE?
• Later multicomponent theories
–Guilford; 180 basic mental abilities
»Structure-of-intellect model
»Content, operations, products
–Cattell & Horn
»Fluid – solve novel, abstract
problems
»Crystallized – solve problems
depending on acquired knowledge
•
Figure 9.2 An item from one of Guilford’s tests of social intelligence. The task is to read the
characters’ expressions and to decide what the person marked by the arrow is most probably
saying to the other person. You may wish to try this item yourself (the correct answer appears
below). ADAPTED FROM GUILFORD, 1967.
WHAT IS INTELLIGENCE?
• A recent hierarchical model
–Carroll – three-stratum theory
»g at top of pyramid
»8 broad abilities at second level
»Narrow third-stratum abilities
WHAT IS INTELLIGENCE?
• A Modern Information-Processing Viewpoint
– Sternberg – triarchic theory of intelligence
• The Contextual Component
–Context, practical intelligence
• The Experiential Component
–Experience with test items
–Automatization
• The Componential Component
–Information processing strategies
•
Figure 9.4 Sternberg’s triarchic theory of intelligence.
WHAT IS INTELLIGENCE?
• Gardner’s Theory of Multiple Intelligences
– 9 distinctive kinds of intelligence
• Linked to a specific area of the brain
• Follows a different developmental
course
• Each is independent of the others
–This is a point of controversy; some
intelligences are moderately
correlated
•
Table 9.1 Gardner’s Multiple Intelligences
•
Table 9.1 Gardner’s Multiple Intelligences
HOW IS INTELLIGENCE MEASURED?
• The Stanford-Binet Intelligence Scale
– Original version
• IQ of children 3 to 13
• Based on mental age / chronological
age (MA/CA * 100)
– Revised version – still in use
• Normed on individuals 6 through adult
• Deviation score compared with same
aged others; 100 still average
HOW IS INTELLIGENCE MEASURED?
• The Weschler Scales
– Weschler Intelligence Scale for Children-IV
(WISC-IV)
• 6 to 16 years
– Weschler Preschool and Primary Scale of
Intelligence-III (WPPSI-III)
• 3 to 8 years
• Both contain verbal subtests, and
nonverbal subtests
HOW IS INTELLIGENCE MEASURED?
• Normally distributed around an IQ of 100
– Average score is set at 100
– Most scores between 85 and 115
– Very few beyond 130
– Few below 70, common definition of
mental retardation
•
Figure 9.5 The approximate distribution of IQ scores people make on contemporary intelligence
tests. These tests are constructed so that the average score made by examinees in each age
group is equivalent to an IQ of 100. Note that more than two-thirds of all examinees score within
15 points of this average (that is, IQ’s of 85-115) and that 95 percent of the population scores
within 30 of average (IQ’s of 70-130). ADAPTED FROM SATTLER, 1992.
•
Table 9.2 The Meaning of Different IQ Scores
HOW IS INTELLIGENCE MEASURED?
• Group Tests of Mental Performance
– More cost effective
– Paper and pencil measures
– Assess a group rapidly
• SAT
• ACT
HOW IS INTELLIGENCE MEASURED?
• Newer Approaches to Intelligence Testing
– The Kaufman Assessment Battery for
Children (K-ABC)
• Based on information-processing theory
• Uses dynamic assessment
–How well new material is learned with
competent instruction
»Based on Vygotsky and Sternberg
HOW IS INTELLIGENCE MEASURED?
• Assessing Infant Intelligence
– Bayley Scales of Infant Development
• Motor scale
• Mental scale – categorizing, searching
for objects; following directions
• Infant Behavioral Record
• Motor and Mental combine to form DQ
(developmental quotient)
• Poor predictor of childhood IQ
•
Table 9.3 Description of Sub-Scales of the Bayley Scale of Infant Development
HOW IS INTELLIGENCE MEASURED?
– New Evidence for Continuity in Intellectual
Performance
• Visual reaction time
• Rate of habituation
• Preference for novelty
–All three moderately correlated with
childhood IQ (average = .45)
HOW IS INTELLIGENCE MEASURED?
• Stability of IQ in Childhood and Adolescence
– Starting around age 4, relationship
between early and later IQ’s
– Becomes stronger with age
– Large individual differences
• 50% had average variations of over 20
points
– Measures intellectual performance, not
necessarily capacity in the future
•
Table 9.4 Correlations of IQ’s Measured during the Preschool Years and Middle Childhood, with
IQ’s Measured at Ages 10 and 18. SOURCE: Adapted from Honzik, MacFarlane, & Allen, 1948.
HOW IS INTELLIGENCE MEASURED?
• Stability, continued
– IQ increases – children from stable,
intellectually stimulating homes
– IQ decreases – children living in poverty,
especially prolonged
• Cumulative-deficit hypothesis
–Impoverished environments dampen
intellectual growth, effects
accumulate over time
•
Figure 9.6 Mental performance at age 6 years for early-adopted English children and Romanian
orphans adopted at different ages. Notice that the longer the Romanian children had lived in the
barren institutional environment, the lower their cognitive performance at age 6 – a finding that
supports the cumulative-deficit hypothesis. ADAPTED FROM O’CONNER ET Al., 2000.
WHAT DO INTELLIGENCE TESTS PREDICT?
• IQ as a Predictor of Scholastic Achievement
– Good predictor (.50)
• Do better in school
• Stay in school longer
• Go to college
– Best predictor is actually past grades
• Work habits, interests, motivation
WHAT DO INTELLIGENCE TESTS PREDICT?
• IQ as a Predictor of Vocational Outcomes
– IQ is related to occupational prestige/status
• Due to link with education
– Predicts job performance (.50)
• Practical intelligence, also very
important, not measured by IQ
WHAT DO INTELLIGENCE TESTS PREDICT?
• IQ as a Predictor of Health, Adjustment, and
Life Satisfaction
– Terman’s longitudinal study
• Most gifted children were happy, healthy,
and led productive lives
–Disruption of home environment –
divorce, lack of support, worse
outcomes
WHAT DO INTELLIGENCE TESTS PREDICT?
• Health, Adjustment, and Satisfaction, cont.
– Mental retardation sample
• Organic – severe; institutionalized
• Cultural-familial – (mild); low genetic
potential and unstimulating environment
–Less favorable outcomes than
nonretarded,
»Only 20% needed any assistance
»Most married and were satisfied
•
Table 9.5 Midlife Occupations of Mentally Retarded, Nonretarded, and Gifted Males. SOURCE:
Adapted from Ross et al., 1985.
FACTORS THAT INFLUENCE IQ SCORES
• The Evidence for Heredity
– Twin studies – resemblance increases as
genetic similarity increases
– Adoption studies – IQ more similar to
biological than adoptive parents
FACTORS THAT INFLUENCE IQ SCORES
• The Evidence for Environment
– The Flynn Effect
• Improving IQ scores since 1940
–Improvements in education, nutrition,
and health care
– Adoption Studies
• Children leaving impoverished
environments score very well on tests;
higher IQ than predicted
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
• Home Environment and IQ
– Assessing the Home Environment
• HOME inventory – observer can
determine how intellectually stimulating
the home is (45 statements)
• Asks parent about the daily routine
• Observes child and parent interactions
• Notes play materials
•
Table 9.6 Ten Environmental Risk Factors Associated with Low IQ and Mean IQs at Age 4 of
Children Who Did or Did Not Experience Each Risk Factor. SOURCE: Data and descriptions
compiled from Sameroff et al., 1993.
•
Table 9.7 Subscales and Sample Items for the HOME Inventory (Infant Version). SOURCE:
Adapted from Caldwell & Bradley, 1984.
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
– Does the HOME Predict IQ?
• Yes, regardless of social class or
ethnicity; beyond parental IQ or genes
• Which aspects matter most?
–Creating a stimulating environment
–Being involved in child’s learning
–Explaining new concepts
–Providing age appropriate challenges
–Providing consistent encouragement
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
• Social-Class and Ethnic Differences in IQ
– Children from lower- and working-class
homes score 10-15 points lower on IQ
– Children of African-American and NativeAmerican ancestry score 12-15 points
lower than European American classmates
– Hispanic American between, Asian same
as European American or higher
– These are group-level differences
•
Figure 9.7 Approximate distributions of IQ scores from African American and white children reared
by their biological parents. BASED ON BRODY, 1992; NEISSER, ET AL., 1996.
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
• Why Do Groups Differ in Intellectual
Performance?
– Cultural/Test Bias Hypothesis
• Artifact of tests and testing procedures,
favoring white, middle-class students
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
• Does “test bias” explain group
differences
–Same pattern with culture-fair tests
(Raven Progressive Matrices)
–IQ tests predict academic success
equally well for all groups
•
Figure 9.8 An item similar to those appearing in the Raven Progressive Matrices Test.
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
• Motivational factors
–Increasing comfort with testing
situation and examiner can increase
scores
–Negative stereotypes
»Reject behaviors such as excelling
on tests – not relevant to them
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
– Genetic hypothesis
• No conclusive evidence supporting
genetics as causing between-group
differences in intelligence exists!
• Genetics is partly responsible for withingroup differences
•
Figure 9.9 Why within-group differences do not necessarily imply anything about between-group
differences. Here we see that the difference in the heights of the plants within each field reflects
the genetic variation in the seeds that were planted there, whereas the difference in the average
heights of the plants across the fields is attributable to an environmental factor: the soils in which
they were grown. ADAPTED FROM GLEITMAN, 1991.
SOCIAL AND CULTURAL CORRELATES OF
INTELLECTUAL PERFORMANCE
– Environmental hypothesis
• Poor people and minority group
members score lower because
–Impoverished environments
»less conducive to intellectual
development
»Nutrition; Stress
»Supported by research
IMPROVING COGNITIVE PERFORMANCE
THROUGH COMPENSATORY EDUCATION
• Goal – provide disadvantaged children the
educational experiences that middle-class
children were receiving (Head Start)
• Long-term follow-ups
– Higher IQ’s for 2-3 years, then decline
– More likely to meet basic requirements
– More likely to complete high school
– More positive attitudes
– Less likely to be delinquent
IMPROVING COGNITIVE PERFORMANCE
THROUGH COMPENSATORY EDUCATION
• The Importance of Parental Involvement
– Parental involvement is essential
– 2-generation interventions
• The Importance of Intervening Early
– Abecedarian Project
• Began at 6-12 weeks old, continued until
enrolled in school
–Higher IQ, maintained through age 15
•
Figure 9.10 Average academic achievement scores at age 12 for Abecedarian preschool program
participants and control children. ADAPTED FROM CAMPBELL & RAMEY, 1994.
IMPROVING COGNITIVE PERFORMANCE
THROUGH COMPENSATORY EDUCATION
– Chicago longitudinal study
• High quality preschool program – good
• Additional compensatory education –
good
– Although all are expensive, long term
benefits are worth the investment
CREATIVITY AND SPECIAL TALENTS
• Giftedness is defined as
– High IQ (over 140)
– Singular talents (music, art, etc)
• What is Creativity?
– Ability to generate appropriate, novel ideas
– The Psychometric Perspective
• Divergent thinking – many solutions
–Modestly related to IQ
–Home environment very important
•
Figure 9.11 Are you creative? Indicate what you see in each of the three drawings. Below each
drawing you will find examples of unique and common responses, drawn from a study of creativity
in children. ADAPTED FROM WALLACH & KOGAN, 1965.
CREATIVITY AND SPECIAL TALENTS
• The Multicomponent (Confluence)
Perspective – convergence of factors
– Sternberg & Lubart’s Investment Theory
• Intellectual resources
–Find new problems
–Evaluate ideas – good or bad
–Sell others on the value of new ideas
CREATIVITY AND SPECIAL TALENTS
– Sternberg & Lubart’s Theory, continued
• Knowledge
• Cognitive style – legislative – preference
for novel thinking
• Personality – sensible risks,
perseverance, self-confidence
• Motivation – for the work itself, not
rewards
• A supportive environment
CREATIVITY AND SPECIAL TALENTS
• A Test of Investment Theory
– Test examining all factors except
environment showed all to be moderately
to highly correlated with creativity
• Promoting Creativity in the Classroom
– More divergent thinking
– Support for new ideas
– Tolerance for ambiguity