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Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

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Page 1: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Weschler Tests

WAIS: Adult Intelligence ScaleWISC: Intelligence Scale for Children

WPPSI: Preschool and Primary Scale of Intelligence

Page 2: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

History 1939: Weschler Bellvue 1950: WISC 1955: WAIS 1974: WISC-R 1981: WAIS – R 1997: WAIS-III 2002: WPPSI-III 2003: WISC IV

Page 3: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Rationale for Weschler’s tests

More appropriate content for adults on the WAIS

Broader coverage the Stanford Binet

Separate scores for components of intelligence

Better norms

Page 4: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Stratified Sampling in WAIS

For an test to be used for all adults in the US, what variables should stratified on in the sampling?

Page 5: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Variables used to select a stratified sample in WAIS

Age: 13 age groups, 16 to 89 Sex: M, F Race: White, non-white Geographic region: 4 regions Occupation: 6 occupational groups Education Residence: urban, rural

Page 6: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Example using 1995 Census

Consideration of a combination of region, age, and sex

Page 7: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Structure of WAIS Scores on 19 scales in several

content areas: Information, Block Design, Word Reasoning

Scores on traditional theoretical organization of Verbal IQ, Performance IQ, and Full Scale IQ

Scores on four Indices resulting from factor analysis of the 19 content scales

Page 8: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Profile Analysis: pathologies show more scatter, e.g. schizo

Low Middle High Compre X Arith X Similarities X Vocab X Digit X

Block X Coding X Objec Assem X Digit Symbol X

Page 9: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Profile Analysis: Brain damage

Low Middle High

Compre X Arith X Similarities X Vocab X Digit X

Block X Coding X Objec Assem X Digit Symbol X

Page 10: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Profile Analysis: Psychopathic character disorder

Low Middle High

Compre X Arith X Similarities X Vocab X Digit X

Block X Coding X Objec Assem X Digit Symbol X

Page 11: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Group Tests of Cognitive Abilities

Can be administered to more than one person at a time

Historically called “paper and pencil” tests

Now can be administered electronically On computer On line, web-based systems (ISSUES!!)

Page 12: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Advantages

Standardization Examiner has no/small influence Mass testing Multiple choice format simplifies

scoring Scoring can be objective Adaptive testing Better norms

Page 13: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Disadvantages Examiner cannot make observations

about each individual, e.g. is person ill Restrictions on the response mode: just

make on paper (?) More difficult to have individuals take

different questions Difficult to measure certain attributes,

e.g., sensori-motor functions Not appropriate for certain individuals,

e.g., inexperienced with these formats

Page 14: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Scholastic Aptitude Tests

SAT ACT GRE MCAT LSAT

Page 15: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Some Paper and Pencil Tests of “g”

Hidden Figures Test -Gottschaldt Figures

Matrices Raven Progressive Matrices

Figural Patterns Cattell Culture Fair Intelligence Test

Page 16: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Wonderlic Personnel Test A measure of general mental ability “g” Short, timed, 12 minutes Several forms: 11 languages, Braille, large 50 items

Spiral omnibus format: gets more difficult, changing topics

Word comparisons, disarranged sentences, following directions, number comparisons, number series, story problems, spatial, logic

Page 17: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Primary Mental Abilities

Thurstone, 1938 Weschler 7 to 9 cognitive abilities Resulted from theory and research

finding showing clusters of behaviors

Examples of abilities and test items

Page 18: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Verbal comprehension

Vocabulary, synomyms, antonyms, reading

Verbal fluency

Rapid production of words

Number ability

Arith word problems, arith reasoning, arith computation

Spatial visualization

Mental manipulation of symbols and figures

Memory Recall of words, paired associates, coding tasks

Reasoning Analogies, series

Perceptual speed

Cross out “Ls” ALMJLBEL

Page 19: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Multiple Aptitude Test Batteries A “battery” is a coordinated set of tests

measuring several attributes Several test of related abilities

developed, normed, evaluated, and packaged by one publisher

Examples Differential Aptitude Tests (DAT) General Aptitude Test Battery (GATB) Armed Services Vocational Aptitude Battery

(ASVAB)

Page 20: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Differential Aptitude Test (DAT) Verbal Reasoning Numerical Ability Abstract Reasoning Space Relations Mechanical Reasoning Clerical Speed and Accuracy Language Usage Spelling

Page 21: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Psychometric Information on the DAT Norms: national sampling, ½ male and

female, Grades 8 to 12, workers Reliability

Parallel forms: .68 to .86, percentile bands Validity

Predictive of grades in math, science, social studies, English; Follow up study

Support material: brochures, profile forms, career planning using Career Planning Qst

Page 22: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Seven-Year Follow-up Study with DAT

1430 senior high school students examined with DAT, then followed for 7 years to learn what school level and what occupation

Page 23: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Criterion: Education level attained 7 years later

Educ level Advanced degree College graduate Some college Specialty school No further school

Page 24: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Criterion: Education level attained

Educ level Average Verbal Reasoning

Average Numerical

Advanced degree

86 84

College graduate 79 79

Some college 61 57

Specialty school 40 31

No further school

34 30

Page 25: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Criterion:Occupation entered

Job working in?

What test did they get highest score on? And what was mean

Engineers VR = 84, NA = 89

Drafting,engineer aide

SR = 67

Technicians MR = 53

Office jobs Clerical = 64

Sales AR = 58

Page 26: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Other multiple aptitude batteries

General Aptitude Test Battery (GATB) Used in US employment offices Controversy over race norming; CRA

of 1991 Armed Forces Vocational Test

Battery (ASVAB) Used in military induction centers

Page 27: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Guilford’s Structure of Intellect Model

“Search model” – has heuristic value 120 facets of intelligence 5 Operations: kinds of mental

processes 4 Contents:what you are thinking

about 6 Products: the form in which the

information occurs

Page 28: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Ex: Cognition of semantic…

Units: vocabulary, synonyms Classes: verbal classifications Relations: verbal analogies, order Systems: arithmetic operations Transformations: similarities Implications: “Effects” test

Page 29: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Creativity: Divergent Thinking about ….

Various Content <-->

Various Products

Figures Units

Symbols Classes

Word = semantics Relations

Behaviors Systems

Transformations

Implications

Page 30: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Other Tests of Specific Abilities

Emotional Intelligence Gardner’s Multiple Intelligences

Page 31: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Disabilities and Testing

Diagnosing disabilities Accommodating disabled

individuals in testing

Page 32: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Definitions

Child experiencing delays, or has condition which will result in delay Individuals With Disabilities Act

(1997) Adult with a physical or mental

impairment that limits a major life activity American With Disabilities Act (1990)

Page 33: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Diagnosing disabilities

Must be done by a qualified examiner

Must be documented in some formal, proven way

Poor performance is not necessarily the result of a disability

Page 34: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Assessing various types of disabilities Physical

Vision: optical expert Hearing: audiologist Motor: special ed person, PT, med doc

Mental/cognitive Mental retardation: “IQ” tests: WISC Adaptive behavior: Vineland Emotional: personality tests, behavioral

observations

Page 35: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Accommodations

Access Services Testing

Forms, mode of response, environment, aids, time allowed

Standards for Educ and Psych Tests Ethical Principles of Psychologists

Page 36: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Two Points of View

Tests are biased

Tests are not biased

Page 37: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Psychometric Terms related to test bias Adverse Impact

Mean difference in scores Disproportionate selection rates

Bias in measurement = slope bias Differential validity: difference in r

Bias in prediction = intercept bias Unfair discrimination Systematic under-prediction of success

Page 38: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

“Tests are biased”

Arguments that cognitive ability tests are BIASED and should NOT be used to assess minorities

Page 39: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are biased African Americans score 10-15 points

lower than whites; Hispanic/Latinos score 5 – 7 points lower than whites

5 point difference remains after using controls

IQ tests have white, anglo-saxon, middle class content

Ethnic minorities score lower because of differences in motivation and exposure to tests

Page 40: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are biased, continued Tests are differentially valid (slope bias) Tests under-predict success for minorities

(“intercept bias”) Validation research has used poor criteria Test results induce negative expectations IQ is partially environmentally determined Use alternatives

Page 41: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Heritability Heritability is the proportion of total

variance in test scores due to genetic factors: h squared

Total test variance = variance due to genetics + variance due to environment

Estimates of heritability in cognitive ability: Some testing texts: 30- 40% General literature: 50 – 70% Older ages: 80%

Page 42: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Twins’ studies

Correlation of test scores

Identical twins reared together

.91

Identical twins reared apart .75

Fraternal twins reared together

.55

Fraternal twins reared apart .30

Siblings .50

Natural parent and child .44

Adoptive parent and child .02

Page 43: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are not biased

Arguments that cognitive ability tests are NOT biased and should be used to assess minorities

Page 44: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are not biased

African Americans and Hispanis score lower on numerous tests of cognitive ability

Test score differences persist even after controls for SES and even with the use of culture free and culture fair cognitive tests

Culturally different individuals from other groups do as well as whites

White examiners do not treat minority examinees differently

Page 45: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are not biased Differential validity (“slope bias”)

occurs no more frequently than chance. Well developed tests are equally valid

Tests do not under-predict success for minorities; if any thing they over-predict success for minorities

Cognitive ability tests predict success in school, occupations, military, life

Page 46: Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

Tests are not biased Tests provide diagnosis and help

identify special educ and enrichment

Tests serve to evaluate outcomes of program; part of solution

IQ is partially (largely) genetically determined

Alternative are more biased; tests are “color blind”