Myers’ PSYCHOLOGY

(5th Ed)

Chapter 11

Intelligence

James A. McCubbin, PhDClemson University

Worth Publishers

Origins of Intelligence

Intelligence Test a method of assessing an

individual’s mental aptitudes and comparing them to those of others, using numerical scores

Origins of Intelligence

Mental Age a measure of intelligence test

performance devised by Binet chronological age that most

typically corresponds to a given level of performance

child who does as well as the average 8-year-old is said to have a mental age of 8

Origins of Intelligence

Stanford-Binet the widely used American

revision of Binet’s original intelligence testrevised by Terman at Stanford

University

Origins of Intelligence

Intelligence Quotient (IQ) defined originally the ratio of

mental age (ma) to chronological age (ca) multiplied by 100 IQ = ma/ca x 100)

on contemporary tests it is the average performance for a given age is assigned a score of 100

What is Intelligence?

Intelligence capacity for goal-directed and adaptive behavior

involves certain abilities profit from experiencesolve problemsreason effectively

What is Intelligence?

IQ is a score on a test it is not something you have

Is intelligence singular or multiple abilities?

Does it relate to speed of brain processing?

Intelligence

Is intelligence culturally defined?

Are intelligence tests culture free?

Are There Multiple Intelligences?Factor Analysis

statistical procedure that identifies clusters of related items (called factors) on a test

used to identify different dimensions of performance that underlie one’s total score

General Intelligence (g) factor that Spearman and others believed

underlies specific mental abilities measured by every task on an intelligence test

Are There Multiple Intelligences?

Savant Syndrome condition in which a person

otherwise limited in mental ability has an amazing specific skillcomputation drawing

Are There Multiple Intelligences?

Social Intelligence the know-how involved in

comprehending social situations and managing oneself successfully

Emotional Intelligenceability to perceive, express,

understand, and regulate emotionscritical part of social intelligence

Brain Function and Intelligence

People who can perceive the stimulus very quickly tend to score somewhat higher on intelligence tests

Stimulus Mask

Question: Long side on left or right?

Assessing Intelligence

Aptitude Test a test designed to predict a

person’s future performance aptitude is the capacity to learn

Achievement Test a test designed to assess what a

person has learned

Assessing Intelligence

Wechsler Adult Intelligence Scale (WAIS) most widely used intelligence test subtests

verbal performance (nonverbal)

Wechsler Intelligence Scale for Children (WISC) similar to WAIS, but for school children

Assessing Intelligence- Sample Items from the WAIS

From Thorndike and Hagen, 1977

VERBAL

General Information Similarities Arithmetic ReasoningVocabularyComprehensionDigit Span

PERFORMANCE

Picture Completion Picture ArrangementBlock DesignObject AssemblyDigit-Symbol Substitution

Assessing Intelligence

Standardization defining meaningful scores by comparison with

the performance of a pretested “standardization group”

Normal Curve the symmetrical bell-shaped curve that

describes the distribution of many physical and psychological attributes

most scores fall near the average, and fewer and fewer scores lie near the extremes

The Normal Curve

Ninety-five percent of all people fall within 30 points

of 100

Number of

scores

55 70 85 100 115 130 145 Wechsler intelligence score

Sixty-eight percentof people score within 15 points

above or below 100

Getting Smarter?

Intelligence test performance has been rising

70

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1910 1920 1930 1940 1950 1960 1970 1980 1990

Year

IQ scores

Assessing IntelligenceReliability

the extent to which a test yields consistent results

assessed by consistency of scores on:two halves of the testalternate forms of the testretesting the same individual

Validity the extent to which a test measures or

predicts what it is suppose to

Assessing IntelligenceContent Validity

the extent to which a test samples the behavior that is of interest driving test that samples driving tasks

Criterion behavior (such as college grades) that a

test (such as the SAT) is designed to predict

the measure used in defining whether the test has predictive validity

Assessing Intelligence

Predictive Validity success with which a test predicts

the behavior it is designed to predict assessed by computing the

correlation between test scores and the criterion behavior

also called criterion-related validity

Assessing Intelligence

As the range of data under consideration narrows, its predictive power diminishes.

Therefore, the predictive power of aptitude tests scores diminish as students move up the educational ladder.

Greater correlationover broad rangeof body weights

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Little corre-lation withinrestricted

range

Football linemen’s

success

Body weight in pounds180 250 290

The Dynamics of Intelligence

Mental Retardation a condition of limited mental ability indicated by intelligence scores

below 70 produces difficulty in adapting to

the demands of life varies from mild to profound

The Dynamics of Intelligence

Down syndrome retardation and associated

physical disorders caused by an extra chromosome in genetic make-up

The Dynamics of IntelligenceDegrees of Mental Retardation

Level Typical Intelligence Scores Percentage of the Retarded Adaptation to Demands of Life

Mild 50-70 85% May learn academic skills up to sixth-grade level. Adults may, with assistance, achieve self-supporting social and vocational skills.

Moderate 35-49 10 May progress to second-grade level. academically. Adults may contribute to their own support by labor in sheltered workshops.

Severe 20-34 3-4 May learn to talk and perform simple work tasks under close supervision but are generally unable to profit from vocational training.

Profound Below 20 1-2 Require constant aid and supervision.

The Dynamics of Intelligence

Creativity the ability to produce novel and

valuable ideas components of creativity

expertiseimaginative thinking skillsventuresome personalityintrinsic motivationcreative environment

Genetic Influences

The most genetically similar people have the most similar scores

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1.0Similarity ofintelligence

scores(correlation)

Identicaltwinsreared together

Identicaltwinsreared apart

Fraternaltwinsreared together

Siblingsreared together

Unrelatedindividualsreared together

Heritability the proportion of

variation among individuals that we can attribute to genes

variability depends on range of populations and environments studied

Genetic Influences

Similarity ofintelligence

scores(correlation)

Adoptedchildren

andbiologicalparents

Adoptedchildren

andadoptiveparents

Genetic Influences

Group differences and environmental impact

Variation within group

Variation within group

Difference within group

Poor soil Fertile soil

Seeds

Genetic Influences

The Mental Rotation Test of Spatial Abilities

Which two circles contains configuration of blocksidentical to the one in the circle at left?

Standard Responses