copyright © allyn & bacon 2007 chapter 11 testing and individual differences

Copyright © Allyn & Bacon 2007

Chapter 11Chapter 11

Testing and 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.

How Do We MeasureHow Do We MeasureIndividual Differences?Individual Differences?


Validity and ReliabilityValidity and Reliability

Validity –A property exhibited by a test that measures what it purports to measure.• Face validity• Content validity• Criterion validity


ValidityValidity

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.


Validity and ReliabilityValidity 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


ReliabilityReliability

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.


Standardization and NormsStandardization and Norms

Normal range Scores falling near the middle of a normal distribution.


The Normal Distribution of IQ ScoresThe Normal Distribution of IQ Scores

0 10 20 30 40 50 60 70 80 90 110 120 130 140 150 160 170 180 190 200100

Few

Many

Num

ber

of P

erso

ns

IQ

Nor

mal

Ran

ge


Types of TestsTypes 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.


Ethics and Standards in TestingEthics 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


How is IntelligenceHow is IntelligenceMeasured?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.



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.


How to Calculate IQHow to Calculate IQ

IQ = x 100Chronological Age

Mental Age



• 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.



• 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


What Are the ComponentsWhat Are the Componentsof Intelligence?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.


Theories of IntelligenceTheories of Intelligence

• Charles Spearman

g Factor

• A general ability, proposed by Spearman as the main factor underlying all intelligent mental activity.


Theories of IntelligenceTheories 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.


Robert Sternberg’sRobert Sternberg’s Triarchic Theory Triarchic Theory

Practical Practical IntelligenceIntelligence

Analytical Analytical IntelligenceIntelligence

Creative Creative IntelligenceIntelligence


Sternberg’s Triarchic TheorySternberg’s Triarchic Theory

Ability to cope with the environment; “street smarts”

Practical Practical IntelligenceIntelligence

Analytical Intelligence

Creative Intelligence



Ability to analyze problems and find correct answers; ability measured by most IQ tests

also called logical reasoning

Practical Intelligence

Analytical Analytical IntelligenceIntelligence

Creative Intelligence



Form of intelligence that helps people see new relationships among concepts; involves insight and creativity

Practical Intelligence

Analytical Intelligence

Creative Creative IntelligenceIntelligence


Howard Gardner’sHoward Gardner’s Multiple Intelligences Multiple Intelligences

LinguisticLinguistic

Logical-MathematicalLogical-Mathematical

SpatialSpatial

MusicalMusical

Bodily-KinestheticBodily-Kinesthetic

InterpersonalInterpersonal

IntrapersonalIntrapersonal


Gardner’s Multiple IntelligencesGardner’s Multiple Intelligences

LinguisticLinguistic

Logical-Mathematical

Spatial

Musical

Bodily-Kinesthetic

Interpersonal

Intrapersonal

Often measured on IQ tests with reading comprehension and vocabulary tests



Linguistic

Logical-MathematicalLogical-Mathematical

Spatial

Musical

Bodily-Kinesthetic

Interpersonal

Intrapersonal

Often measured on IQ tests with analogies, math problems and logic problems



Linguistic


SpatialSpatial

Musical

Bodily-Kinesthetic

Interpersonal

Intrapersonal

Ability to form mental images of objects and think about their relationships in space



Linguistic


Spatial

MusicalMusical

Bodily-Kinesthetic

Interpersonal

Intrapersonal

Ability to perceive and create patterns of rhythms and pitches



Linguistic


Spatial

Musical

Bodily-KinestheticBodily-Kinesthetic

Interpersonal

Intrapersonal

Ability for controlled movement and coordination



Linguistic


Spatial

Musical

Bodily-Kinesthetic

InterpersonalInterpersonal

Intrapersonal

Ability to understand other people’s emotions, motives and actions



Linguistic


Spatial

Musical

Bodily-Kinesthetic

Interpersonal

IntrapersonalIntrapersonal

Ability to know oneself and to develop a sense of identity


Gardner’s Three New IntelligencesGardner’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.


How Do Psychologists How Do Psychologists Explain IQ DifferencesExplain IQ Differences

Among Groups?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.


How Do Psychologists Explain IQ How Do Psychologists Explain IQ Differences Among Groups?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


Heritability and Group DifferencesHeritability and Group Differences

Heritability – Amount of trait variation within a group, raised under the same conditions, that can be attributed to genetic differences.


Heritability and Group DifferencesHeritability 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.


End of Chapter 11End of Chapter 11

copyright © allyn & bacon 2007 chapter 11 testing and individual differences

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