Intelligence Testing
Melissa Stern
PSY 4930
October 3, 2006
What is Intelligence?
A loaded question . . .
 Ability to modify one’s behavior to meet
demands of the situation
 Abstract reasoning (using symbols or mental
representations)
 Capacity to acquire knowledge
 Problem solving ability
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Definition of Intelligence
Common to many definitions of intelligence
 Knowledge-based thinking
 Apprehension
 Adaptive purposeful striving
 Fluid analytic reasoning
 Mental playfulness
 Idiosyncratic learning
Theories of Intelligence
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Terman coined the term “Intelligence Quotient” (IQ)
in 1916
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Mental age/Chronological age
Spearman’s 2 Factor Theory (1927)
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Intelligence =
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General factors (g) — “mental energy”
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Specific factors (s) — less complex tasks
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E.g., abstract reasoning, problem solving
E.g., motor speed, attention, v-m coordination, memory
Although originally a 2 factor theory, g is the only factor
that accounts for correlations among intellectual abilities
Theories of Intelligence
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Thurstone’s Multidimensional Theory (1938)
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Eight primary mental factors
 Verbal,
perceptual speed, inductive reasoning,
number, rote memory, deductive reasoning, word
fluency, space or visualization)
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He eventually found that these factors correlated
and later postulated a second-order factor similar
to “g”
Multiple Intelligences?
MUSICAL INTELLIGENCE
Is it a type of an intelligence?
Or is it just special talents?
Discuss!
Theories of Intelligence
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Cattell & Horn’s Fluid and Crystallized Intelligence
(1966)
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Fluid intelligence=one’s inborn abilities largely
determined by genetics and biology
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Crystallized Intelligence=acquired skills and knowledge
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Fluid intelligence develops through childhood and adolescents
Examples: number/letter series, matrices
Influenced by environment and culture
Continues to develop over the lifespan
Examples: vocabulary, general information
Some tasks measure both:
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Arithmetic reasoning
Theories of Intelligence
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Piaget’s Developmental Theory
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Hierarchical model with four major periods of
cognitive development
 Sensorimotor
period
 Preoperational period
 Concrete operations period
 Formal operations period
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Correlations have been found between Piagetian
tasks and psychometric scales of intelligence
A Modern View of Intelligence

Intelligence is an integrated construct
including:
Biological—dependent on genetics, brain
structure, physiological functioning of brain
 Cognitive—metacognition and ordinary cognition
 Motivational—magnitude, direction, and
disposition of individual
 Behavioral—behavior in academic, social, and
adaptive domains
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Genetically-determined intelligence is always
modified by experience
Environmental Influences on IQ
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Factors that enhance IQ:
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Stimulating environment
Good medical care/nutrition
Parental involvement in learning
Rich language environment
Factors that negatively impact IQ:
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Persistent poverty
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Perinatal complications, inadequate stimulation in environment,
lead exposure
Large family size
Nutrition during gestation and early childhood
Heredity and IQ
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“Heredity may limit a child’s potential, but
environment permits their potential to be
actualized” (Sattler, 2001, p. 180)
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We inherit genes, not an actual IQ
Genetics is only 1 factor affecting IQ (familial,
educational, nonfamilial factors)
 IQ can change, but it is difficult
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Does seem to go up on average about 4 points
between childhood and adolescence (develop
problem-solving strategies over time)
The Bell Curve (1994)
Controversial book on the social
ramifications of IQ stratification
 The “Cognitive Elite” associate with other
elite
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Physical separation from others
 Make
more money
 Live in different neighborhoods
The Bell Curve: Social
Problems and IQ
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Poverty -  IQ predicts poverty, even more than
SES in which people grow up
Schooling -  IQ increases risk of dropping out of
school and decreases chances of college degree
Unemployment, Idleness and Injury -  IQ is
associated with unemployment, frequent injury, or
idleness (removing oneself from the workforce)
Family -  IQ is related to high rates of divorce,
lower rates of marriage, and higher rates of
illegitimate births
The Bell Curve: Social
Problems & IQ
Welfare Dependency -  IQ increases the
chances of chronic welfare dependency
 Parenting -  IQ of mothers correlates with
low birth weight babies, poor child motor
skills and social development, and children’s
behavioral problems
 Crime -  IQ increases the risk of criminal
behavior
 Civility and Citizenship – those with  IQ
vote least often
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The Bell Curve: Gender,
Ethnicity & IQ
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Few gender differences were found
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Males higher on spatial and quantitative
Females higher on verbal ability
East Asians score highest, then European
Americans, Hispanics, and African Americans
APA task force on IQ
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IQ can predict individual differences, but not necessarily
group differences
Socioeconomic influences may play a role
Cultural differences may affect education
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emphasis on spirituality, harmony, movement, verve, affect,
expressive individualism, communalism, etc.
IQ Tests and Culture
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Culturally Biased
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Proponents of this view feel IQ tests are biased
against ethnic minorities and don’t take their
sociocultural factors into account
Culturally loaded
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Proponents of this view feel IQ tests are
reflective of the knowledge and skills of the
dominant society (those who created the test)
Pros and Cons of IQ Testing
Pros
Reveals unknown talent
Standardized method of
comparing children
Cons
Self-fulfilling prophecy
Measures only processes
needed for successful test
performance
Excellent predictors of
Biased against ethnic
academic performance
minorities
Valuable for children with Poor predictors of real-life
disabilities
situations
Predicts success in a
Unconventional
wide variety of endeavors responses are penalized
Common IQ Misperceptions
IQ is innate
 IQ never changes
 IQ tests provide perfectly reliable scores
 All IQ tests measure the same thing
 IQ test scores are interchangeable
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IQ tests vs. Achievement tests
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IQ tests measure broader abilities
IQ tests are more predictive of future performance
Achievement tests (reading, math, etc.) are heavily
dependent on formal learning at home or school
Achievement test scores change more readily
Achievement tests assess mastery of factual
information; IQ tests assess ability to apply
information in new ways
Common Intelligence Tests
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Stanford-Binet Intelligence Scale
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Wechsler Intelligence Scale (WISC)
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For children 6-16 years
Currently in the 4th edition (2003)
Wechsler Preschool and Primary Scale of
Intelligence (WPPSI)
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Originally developed in 1916
Currently in the 4th edition
For children 3 years to 7 years, 3 months
Bayley Scales of Infant Development (BSID)
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For children aged 1 to 42 months
Cognitive, Motor, and Behavioral scales
IQ Test example: WISC-IV
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15 subtests (some of them are optional)
Administration time varies from 1-3 hours
Must be trained in order to administer – complicated rules
Provides
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Full Scale IQ--Global estimate of child’s general intellectual
capacity/potential/level of cognitive ability and the relative standing
compared to the normative population
Verbal Comprehension Index –verbal reasoning skills
Perceptual Reasoning Index – nonverbal reasoning skills
Working Memory –ability to attend to and hold information in memory
to formulate responses
Processing Speed – speed of processing information
Uses the deviation IQ (mean = 100, SD = 15)
WISC-IV Subtests
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Block Design
Similarities
Digit Span
Picture Concepts
Coding
Vocabulary
Letter-Number Sequencing
Matrix Reasoning
Comprehension
Symbol Search
(Picture Completion)
(Cancellation)
(Information)
(Arithmetic)
(Word Reasoning)
Matrix Reasoning Example
WISC-III Subtests
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VCI
Similarities
Vocabulary
Comprehension
Information*
Word Reasoning*
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PRI
Block Design
Picture Concepts
Matrix Reasoning
Picture Completion*
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WMI
Digit Span
Letter-Number Sequencing
Arithmetic*
PSI
Coding
Symbol Search
Cancellation*
IQ Testing Considerations
Examiner variability (i.e., giving extra help,
errors in administration, incorrect scoring,
etc.)
 Situational variability (i.e., on/off medications,
Ritalin, fatigue, illness, hunger, etc.)
 Individual subtest scores are not as reliable
as the FSIQ and Indices
 Qualitative observations are also important
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Types of IQ
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Ratio IQ
First type of IQ
Stern (1938)
IQ = MA/CA x 100
Same IQ has different
meanings at different
ages
Not used as often now
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Deviation IQ
A type of standard
score
Mean = 100, SD =
15/16
Compares IQ to same
age peers
Normal distribution
WISC uses this