Intelligence TestsIntelligence Tests

Lecture 18Lecture 18

DefinitionDefinition““Intelligence tests are psychological tests that Intelligence tests are psychological tests that are designed to measure a variety of mental are designed to measure a variety of mental functions, such as reasoning, comprehension, functions, such as reasoning, comprehension, and judgment”.and judgment”.

PurposePurposeTo obtain an idea of the person's intellectual To obtain an idea of the person's intellectual potential.potential.

Precautions with Intelligence Tests Precautions with Intelligence Tests

There are many different types of intelligence There are many different types of intelligence tests and they all do not measure the same tests and they all do not measure the same abilities.abilities.

The test should be adequately developed and The test should be adequately developed and have solid research to show its reliability and have solid research to show its reliability and validity. validity.

Test should only be administered and Test should only be administered and interpreted by a trained professional.interpreted by a trained professional.

Criticism of intelligence testsCriticism of intelligence tests A central criticism : psychologists and educators use these A central criticism : psychologists and educators use these

tests to distribute the limited resources of our society.tests to distribute the limited resources of our society.

Intelligence test scores have not only become associated with a Intelligence test scores have not only become associated with a person's ability to perform certain tasks, but with self-worth.person's ability to perform certain tasks, but with self-worth.

False assumptions about biological or environmental False assumptions about biological or environmental intelligence.intelligence.

Associated with categorizing and stereotyping people.Associated with categorizing and stereotyping people.

May affect a person's aspirations and motivation to obtain May affect a person's aspirations and motivation to obtain goals.goals.

Can be culturally biased against certain groups.Can be culturally biased against certain groups.

Common ProceduresCommon Procedures A person can expect to do a variety of tasks.A person can expect to do a variety of tasks.

E.g., having to answer questions that are asked E.g., having to answer questions that are asked verbally, doing mathematical problems, and doing a verbally, doing mathematical problems, and doing a variety of tasks that require eye-hand coordination.variety of tasks that require eye-hand coordination.

Some tasks may be timed and require the person to Some tasks may be timed and require the person to work as quickly as possible. work as quickly as possible.

Most questions and tasks start out easy and Most questions and tasks start out easy and progressively get more difficult.progressively get more difficult.

Common Procedures (contd.)Common Procedures (contd.) Raw scores on an intelligence test are typically Raw scores on an intelligence test are typically

converted to standard scores for comparison.converted to standard scores for comparison.

Depending on the intelligence test that is used, a Depending on the intelligence test that is used, a variety of scores can be obtained. variety of scores can be obtained.

Most intelligence tests generate an overall Most intelligence tests generate an overall intelligence quotient or IQ.intelligence quotient or IQ.

It is valuable to know how a person performs on the It is valuable to know how a person performs on the various tasks that make up the test. This can various tasks that make up the test. This can influence the interpretation of the test and what the influence the interpretation of the test and what the IQ means.IQ means.

AdvantagesAdvantages Intelligence tests measure a wide variety of human Intelligence tests measure a wide variety of human

behaviors.behaviors.

Allow professionals to have a uniform way of Allow professionals to have a uniform way of comparing a person's performance with that of other comparing a person's performance with that of other people who are similar in age.people who are similar in age.

Also provide information on cultural and biological Also provide information on cultural and biological differences among people.differences among people.

Excellent predictors of academic achievement and Excellent predictors of academic achievement and provide an outline of a person's mental strengths and provide an outline of a person's mental strengths and weaknesses.weaknesses.

DisadvantagesDisadvantages Some researchers argue that intelligence tests have Some researchers argue that intelligence tests have

serious shortcomings. For example, many intelligence serious shortcomings. For example, many intelligence tests produce a tests produce a single intelligence score.single intelligence score.

This single score is often inadequate in explaining the This single score is often inadequate in explaining the multidimensional aspects of intelligence. multidimensional aspects of intelligence.

Individuals with similar intelligence test scores can Individuals with similar intelligence test scores can vary greatly in their expression of these talents.vary greatly in their expression of these talents.

For example, strong verbal skills vs. strong skills in For example, strong verbal skills vs. strong skills in perceiving and organizing various tasks may lead two perceiving and organizing various tasks may lead two people to have identical scores on intelligence tests. . people to have identical scores on intelligence tests. .

Intelligence tests only measure a sample of behaviors Intelligence tests only measure a sample of behaviors or situations in which intelligent behavior is revealed.or situations in which intelligent behavior is revealed.

For instance, some intelligence tests do not measure For instance, some intelligence tests do not measure a person's everyday functioning, social knowledge, a person's everyday functioning, social knowledge, mechanical skills, and/or creativity.mechanical skills, and/or creativity.

The formats of many intelligence tests do not capture The formats of many intelligence tests do not capture the complexity and immediacy of real-life situations.the complexity and immediacy of real-life situations.

Limited ability to predict non-test or nonacademic Limited ability to predict non-test or nonacademic intellectual abilities.intellectual abilities.

Commonly Used Intelligence Commonly Used Intelligence TestsTests

The three most commonly used intelligence The three most commonly used intelligence tests are:tests are:

Stanford-Binet Intelligence ScalesStanford-Binet Intelligence Scales

Wechsler-Adult Intelligence ScaleWechsler-Adult Intelligence Scale

Wechsler Intelligence Scale for ChildrenWechsler Intelligence Scale for Children

Concepts of IQ & Concepts of IQ & Deviation IQDeviation IQ

THE INTELLIGENCE THE INTELLIGENCE QUOTIENT (IQ)QUOTIENT (IQ)

RATIO IQRATIO IQ: Binet regarded the mental age (MA) as an : Binet regarded the mental age (MA) as an index of mental performance. Each item successfully index of mental performance. Each item successfully passed on a Binet test signified a certain number of passed on a Binet test signified a certain number of months' credit. months' credit.

At the conclusion of the test, the items passed were At the conclusion of the test, the items passed were added up and the Mental Age (MA) emerged. added up and the Mental Age (MA) emerged.

Subsequently, Stern (1938) developed the concept of Subsequently, Stern (1938) developed the concept of intelligence quotient (1Q) to circumvent several intelligence quotient (1Q) to circumvent several problems that had arisen in using the difference problems that had arisen in using the difference between the chronological age (CA) and the MA to between the chronological age (CA) and the MA to express deviance.express deviance.

Computation of The IQ Computation of The IQ

The IQ notion enables us to perform the following The IQ notion enables us to perform the following computation:computation:

IQ=MA/CA x 100IQ=MA/CA x 100

IQs and MAs are merely scores. We can not add or IQs and MAs are merely scores. We can not add or subtract IQ scores.subtract IQ scores.

All we can do is state that a person with an IQ of 50 is All we can do is state that a person with an IQ of 50 is brighter than a person with an IQ of 25.brighter than a person with an IQ of 25.

Deviation IQ:Deviation IQ: Although initially appealing, the ratio IQ is Although initially appealing, the ratio IQ is

significantly limited in its application to older significantly limited in its application to older age groups.age groups.

To deal with this problem, Wechsler To deal with this problem, Wechsler introduced the concept of introduced the concept of deviation IQ.deviation IQ.

The assumption is made that intelligence is The assumption is made that intelligence is normally distributed throughout the population. normally distributed throughout the population.

A deviation IQ then involves a comparison of A deviation IQ then involves a comparison of an individual's performance on an IQ test with an individual's performance on an IQ test with that of his or her age peers.that of his or her age peers.

The Clinical The Clinical Assessment Of Assessment Of

IntelligenceIntelligence

The Stanford - Binet ScaleThe Stanford - Binet ScaleThe Stanford-Binet Intelligence Scale: Fourth Edition The Stanford-Binet Intelligence Scale: Fourth Edition

(SB: FE) is a standardized test that measures (SB: FE) is a standardized test that measures intelligence and cognitive abilities in children and intelligence and cognitive abilities in children and adults, from age two through mature adulthood.adults, from age two through mature adulthood.

It is a descendant of the It is a descendant of the Binet-Simon scaleBinet-Simon scale which which was developed in 1905 and became the first was developed in 1905 and became the first intelligence test. intelligence test.

The The Stanford-BinetStanford-Binet Intelligence Scale was Intelligence Scale was developed in developed in 19161916 and was revised in and was revised in 19371937, , 19601960, , and and 19861986. The present . The present (4th)(4th) edition was published in edition was published in 19861986 and is called and is called SB-4 SB-4..

Purpose Purpose Originally developed to help place children in Originally developed to help place children in

appropriate educational settings. appropriate educational settings.

It can help determine the level of intellectual and It can help determine the level of intellectual and cognitive functioning in preschoolers, children, cognitive functioning in preschoolers, children, adolescents and adults.adolescents and adults.

Can assist in the Can assist in the diagnosisdiagnosis of a learning disability, of a learning disability, developmental delay, developmental delay, mental retardationmental retardation, or , or giftedness. giftedness.

It is used to provide educational planning and It is used to provide educational planning and placement, neuropsychological assessment, and placement, neuropsychological assessment, and research.research.

DescriptionDescription The Stanford-Binet Intelligence Scale is comprised of The Stanford-Binet Intelligence Scale is comprised of

15 subtests, which are grouped into four cognitive 15 subtests, which are grouped into four cognitive area scores which together determine the composite area scores which together determine the composite score and factor scores.score and factor scores.

These area scores include: These area scores include: Verbal ReasoningVerbal Reasoning, , Abstract/Visual ReasoningAbstract/Visual Reasoning, , Quantitative Quantitative ReasoningReasoning, and , and Short-Term MemoryShort-Term Memory..

The composite score is a global estimate of a person's The composite score is a global estimate of a person's

intellectual functioning (a representation of intellectual functioning (a representation of ““gg”” factor. factor.

1. Verbal reasoning: 1. Verbal reasoning: vocabulary, vocabulary, comprehension, absurdities, verbal relationscomprehension, absurdities, verbal relations

2. Abstract/visual reasoning: 2. Abstract/visual reasoning: pattern analysis, pattern analysis, copying, matrices, paper folding and cutting.copying, matrices, paper folding and cutting.

3. Quantitative reasoning: 3. Quantitative reasoning: quantitative, quantitative, number series, equation building.number series, equation building.

4. Short-term memory: 4. Short-term memory: bead memory, bead memory, memory for sentences, memory for digits, memory for sentences, memory for digits, memory for objects.memory for objects.

Multistage testing: Multistage testing: Each subtest is composed Each subtest is composed of items at varying levels of difficulty, from age of items at varying levels of difficulty, from age 2 to adulthood.2 to adulthood.

The examiner first gives the Vocabulary Test to The examiner first gives the Vocabulary Test to determine the entry point (that is, which item to determine the entry point (that is, which item to start with) for each remaining subtest. start with) for each remaining subtest.

Not all examinees of the same age are given Not all examinees of the same age are given the same items. the same items.

The Wechsler ScalesThe Wechsler Scales

WAIS : WAIS : DavidDavid Wechsler used a deviation IQ Wechsler used a deviation IQ concept. This approach assumes that concept. This approach assumes that intelligence is normally distributed and intelligence is normally distributed and compares individuals with their age peers. compares individuals with their age peers.

This method statistically establishes an IQ of This method statistically establishes an IQ of 100 as the mean for each age group. 100 as the mean for each age group.

As a result, an IQ of 100 means the same thing As a result, an IQ of 100 means the same thing for any person, regardless of the person's age.for any person, regardless of the person's age.

Background of WAISBackground of WAIS

Earlier versions of the Stanford-Binet had a number of Earlier versions of the Stanford-Binet had a number of disadvantages that led David Wechsler in 1939 to disadvantages that led David Wechsler in 1939 to develop the Wechsler-Bellevue Intelligence Scale.develop the Wechsler-Bellevue Intelligence Scale.

It offered items whose content was more appropriate It offered items whose content was more appropriate for and more motivating to adults than the school-for and more motivating to adults than the school-oriented Binet test. oriented Binet test.

The Wechsler-Bellevue Intelligence Scale grouped its The Wechsler-Bellevue Intelligence Scale grouped its items into subtests in order of increasing difficulty.items into subtests in order of increasing difficulty.

Performance Scale & Verbal Scale = Full Scale IQ.Performance Scale & Verbal Scale = Full Scale IQ.

The WAIS-IIIThe WAIS-III Wechsler-Bellevue Intelligence Scale : 1939Wechsler-Bellevue Intelligence Scale : 1939

Wechsler Adult Intelligent Scale (WAIS) : 1955Wechsler Adult Intelligent Scale (WAIS) : 1955

WAIS-R (revised): 1981WAIS-R (revised): 1981

WAIS-III (Wechsler Adult Intelligent Scale-Third WAIS-III (Wechsler Adult Intelligent Scale-Third Edition ) : 1997Edition ) : 1997

WAIS – III is an individually administered measure of WAIS – III is an individually administered measure of intelligence, intended for adults aged 16–89.intelligence, intended for adults aged 16–89.

Purpose Purpose Intended to measure human intelligence reflected in Intended to measure human intelligence reflected in

both verbal and performance abilities. both verbal and performance abilities.

Used in neuropsychological evaluationUsed in neuropsychological evaluation

The WAIS-III is also administered for diagnostic The WAIS-III is also administered for diagnostic purposes.purposes.

E.g., E.g., mental retardationmental retardation, specific learning disabilities, , specific learning disabilities, and and attention-deficit/hyperactivity disorderattention-deficit/hyperactivity disorder (ADHD). (ADHD).

The WAIS elicits three intelligence quotient The WAIS elicits three intelligence quotient scores : an overall intelligence quotient, called scores : an overall intelligence quotient, called the full-scale IQ, as well as a verbal IQ and a the full-scale IQ, as well as a verbal IQ and a performance IQ. performance IQ.

The WAIS also elicits four indices, each based The WAIS also elicits four indices, each based on a different set of subtests: on a different set of subtests: verbal verbal comprehensioncomprehension, , perceptual organizationperceptual organization, , working memoryworking memory, and , and processing speedprocessing speed..

ResultsResults

The Verbal IQThe Verbal IQVEBAL SUBSETSVEBAL SUBSETS information, information, digit span, digit span, vocabulary, vocabulary, arithmetic, arithmetic, comprehension, comprehension, similarities, and similarities, and letter-number sequencing letter-number sequencing

The Performance IQThe Performance IQSUBSETSSUBSETS picture completion, picture completion, picture arrangement, picture arrangement, block design, block design, object assembly, object assembly, digit symbol, digit symbol, matrix reasoning, and matrix reasoning, and symbol search symbol search

Precautions Precautions

WAIS III is not considered adequate measure WAIS III is not considered adequate measure of extremely high and low intelligence.of extremely high and low intelligence.

The age range for the WAIS III overlaps with The age range for the WAIS III overlaps with that of the that of the WISCWISC for people between 16 and 17 for people between 16 and 17 years of age (WISC provides a better measure years of age (WISC provides a better measure for this age range).for this age range).

WAIS administrators must receive proper WAIS administrators must receive proper training and be aware of all test guidelines.training and be aware of all test guidelines.

The WISC-IIIThe WISC-III WISC III is an individually administered WISC III is an individually administered

measure of intelligence intended for children measure of intelligence intended for children aged six years to 16 years and 11 months. aged six years to 16 years and 11 months.

First developed in 1949 (WISC),First developed in 1949 (WISC),

Revised in 1974 (WISC-R), Revised in 1974 (WISC-R),

The latest version, the Wechsler Intelligence Scale for The latest version, the Wechsler Intelligence Scale for Children-Third Edition (WISC-III),Children-Third Edition (WISC-III), was published in was published in 1991.1991.

Purposes Purposes Designed to measure human intelligence as reflected Designed to measure human intelligence as reflected

in both verbal and nonverbal (performance) abilities.in both verbal and nonverbal (performance) abilities.

Used in schools as part of placement evaluations for Used in schools as part of placement evaluations for programs for gifted children and for children who are programs for gifted children and for children who are developmentally disabled.developmentally disabled.

Neuropsychological evaluation, specifically with regard Neuropsychological evaluation, specifically with regard to to brainbrain dysfunction. dysfunction.

Also used for other diagnostic purposes.Also used for other diagnostic purposes.

ResultsResults WISC III scores yield an overall intelligence WISC III scores yield an overall intelligence

quotient, called the quotient, called the full scale IQfull scale IQ, as well as a , as well as a verbal IQverbal IQ and a and a performance IQperformance IQ..

Verbal and performance IQ scores are based Verbal and performance IQ scores are based on scores on the 13 subtests.on scores on the 13 subtests.

The full scale IQ is derived from the child's The full scale IQ is derived from the child's scores on all of the subtests and reflects both scores on all of the subtests and reflects both verbal IQ and performance IQ.verbal IQ and performance IQ.

Verbal IQVerbal IQ The child's verbal IQ score is derived from The child's verbal IQ score is derived from

scores on six of the subtests: scores on six of the subtests:

information, information, digit span, digit span, vocabulary, vocabulary, arithmetic, arithmetic, comprehension, comprehension, similarities.similarities.

Performance IQPerformance IQ The child's performance IQ is derived from The child's performance IQ is derived from

scores on the remaining seven subtests: scores on the remaining seven subtests:

picture completion, picture completion, picture arrangement, picture arrangement, block design, block design, object assembly, object assembly, coding, coding, mazes, mazes, symbol search.symbol search.

ConclusionConclusion

The Clinical Use Of Intelligence The Clinical Use Of Intelligence TestsTests

The estimation of general intellectual levelThe estimation of general intellectual level

Prediction of academic successPrediction of academic success

The appraisal of style (person’s The appraisal of style (person’s characteristics)characteristics)