Chapter 11
Testing and Individual
Differences
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How Do We Measure
Individual Differences?
Measuring individual
differences is an essential
component of psychology, but
strict guidelines and ethical
standards must be followed to
ensure results and conclusions
are valid and appropriate.
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Validity and Reliability
Validity –
A property exhibited by a test that
measures what it purports to measure.
• Face validity
• Content validity
• Criterion validity
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Validity
Face validity
• Measures whether a test looks like it tests
what it is supposed to test.
Content validity
• Each item is representative of the larger body
of knowledge about the subject that the test
covers.
Criterion validity
• Accurately measures performance of the test
taker against a specific learning goal.
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Validity and Reliability
Reliability –
A property exhibited by a test that yields
the same results over time.
• Test-retest reliability
• Split-half reliability
• Inter-rater reliability
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Reliability
Test-retest reliability
• People get about the same scores when they
take the test more than once.
Split-half reliability
• A test is split into 2 parts and an individual’s
scores on both halves are compared.
Inter-rater reliability
• A measure of how similarly two different test
scorers would score a test.
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Standardization and Norms
Normal range
Scores falling
near the
middle of a
normal
distribution.
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Types of Tests
• Objective tests can be scored
easily by machine.
• In subjective tests, individuals are given
an ambiguous figure or an open-ended
situation and asked to describe what they
see or finish a story.
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Ethics and Standards in Testing
Ethical concerns related to testing involve:
• The confidentiality of the test results
• How to report the results
• How to use the test to compare
individuals
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How is Intelligence
Measured?
Intelligence testing has a
history of controversy, but
most psychologists now view
intelligence as a normally
distributed trait that can be
measured by performance on
a variety of tasks.
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How is Intelligence
Measured?
Intelligence quotient (IQ) –
A numerical score on an intelligence test,
originally computed by dividing a
person’s mental age by chronological
age and multiplying by 100.
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The Normal Distribution of IQ Scores
Normal Range
Number of Persons
Many
Few
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
IQ
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How to Calculate IQ
Mental Age
IQ =
Chronological Age
x 100
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How is Intelligence
Measured?
• Binet-Simon Test calculated a child’s
mental age and compared it to his or her
chronological age.
• In America, testing became widespread for the
assessment of Army recruits, immigrants, and
school children.
• The Stanford-Binet Intelligence Scale is the
most respected of the new American tests of
intelligence.
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How is Intelligence
Measured?
• Wechsler tests
• Measure a variety of different skills (vocab,
verbal comprehension, arithmetic ability,
similarities, block design, etc.)
• WAIS – Wechsler Adult Intelligence Scale
• WISC – Wechsler Intelligence Scale for Children
• WPPSI – Wechsler Preschool and Primary Scale
of Intelligence
Copyright © Allyn & Bacon 2007
What Are the Components
of Intelligence?
Some psychologists believe
that the essence of
intelligence is a single,
general factor, while others
believe intelligence is best
described as a collection of
distinct abilities.
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Theories of Intelligence
• Charles Spearman
g Factor
• A general ability, proposed by Spearman
as the main factor underlying all
intelligent mental activity.
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Theories of Intelligence
• Raymond Cattell
Crystallized intelligence –
The knowledge a person has
acquired, plus the ability to access
that knowledge.
Fluid intelligence –
The ability to see complex relationships
and solve problems.
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Robert Sternberg’s Triarchic Theory
Practical
Intelligence
Analytical
Intelligence
Creative
Intelligence
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Sternberg’s Triarchic Theory
Practical
Intelligence
Ability to cope with
the environment;
“street smarts”
Analytical
Intelligence
Creative
Intelligence
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Sternberg’s Triarchic Theory
Practical
Intelligence
Analytical
Intelligence
Creative
Intelligence
Ability to analyze
problems and find
correct answers;
ability measured by
most IQ tests
also called logical
reasoning
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Sternberg’s Triarchic Theory
Practical
Intelligence
Analytical
Intelligence
Creative
Intelligence
Form of intelligence
that helps people see
new relationships
among concepts;
involves insight and
creativity
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Howard Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Often measured on IQ
tests with reading
comprehension and
vocabulary tests
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Often measured on IQ
tests with analogies,
math problems and
logic problems
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Ability to form mental
images of objects and
think about their
relationships in space
Bodily-Kinesthetic
Interpersonal
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinesthetic
Ability to perceive and
create patterns of
rhythms and pitches
Interpersonal
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinesthetic
Interpersonal
Ability for controlled
movement and
coordination
Intrapersonal
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
Ability to understand
other people’s
emotions, motives
and actions
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Gardner’s Multiple Intelligences
Linguistic
Logical-Mathematical
Spatial
Musical
Bodily-Kinesthetic
Interpersonal
Intrapersonal
Ability to know oneself
and to develop a
sense of identity
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Gardner’s Three New Intelligences
• Naturalistic intelligence
- Allows people to classify things as
members of diverse groups.
• Spiritual intelligence
- The ability to think in abstract spiritual terms
and to put oneself in a spiritual frame of mind.
• Existential intelligence
- Permits individuals to think about the purpose of
existence and the meaning of things like death and
love.
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How Do Psychologists
Explain IQ Differences
Among Groups?
While most psychologists
agree that both heredity and
environment affect
intelligence, they disagree on
the source of IQ differences
among racial and social
groups.
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How Do Psychologists Explain IQ
Differences Among Groups?
• Hereditarian arguments maintain that
intelligence is substantially influenced by
genetics.
• Environmental approaches argue that
intelligence can be dramatically shaped
by influences such as:
• Health
• Economics
• Education
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Heritability and Group Differences
Heritability –
Amount of trait
variation
within a group,
raised under
the same
conditions,
that can be
attributed to
genetic
differences.
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Heritability and Group Differences
• Research with twins and adopted
children shows genetic influences
on a wide range of attributes,
including intelligence.
• Research has also shown that racial and
class differences in IQ scores can be
eliminated by environmental changes.
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End of Chapter 11
Copyright © Allyn & Bacon 2007