Brief outline of Wechsler's Memory and Intelligence Scales

1. Wechsler
Intelligence and
Memory Scales

2. Wechsler Intelligence Scales

3. Introduction
• Developed by Dr. David Wechsler, a clinical psychologist
• These are individually administered, composite
intelligence tests in a battery format.
• Assessment is done in different areas of intellectual
ability
– Observation of personality in different situations
• Three versions of the test provide 3 different IQ scores
– performance IQ
– verbal IQ
– full scale IQ
• Considered one of the best psychological tests and are
frequently used in clinical practice.

4. History and Development
• In the 1930’s Wechsler studied
various standardized tests and
initially selected 11 subtests.
• “Premise-intelligence” global in
nature and represents some
part of personality.
• 1939: development of the
Wechsler Bellevue
• 1955: development of the
Wechsler Adult Intelligence
Scale (WAIS)
• 1981: development of WAIS-R

5. History and Development
• 1997 development of (WAIS)
– The Wechsler Bellevue originally intended for adults
• 1949 Wechsler Intelligence Scale for Children
(WISC) developed.
• WISC revised in 1974 to WISC-R and in 1991 to
WISC-IV
• 1967 the development of Wechsler Preschool
and Primary School of Intelligence (WPPSI).
• Later revised to WPPSI-R in 1989 then to WPPI-IV
in 2002

6. Forms of the Test
• Wechsler –Bellevue – Has been revised several times
leading to various Editions = WAIS; WAIS R, WAIS III, WAIS
IV
– Initially developed in 1939, and revised in 1946
• Wechsler Adult Intelligence Scale (WAIS ) - Developed in
1955 due to deficiencies primarily linked to both reliability
of the subsets and size of Wechsler –Bellevue
• WAIS - R = Developed in 1981 and was based on 1,880
individuals, considered generally more representative.
– Wechsler Adult Intelligence Scale - III (WAIS -III ) = Developed in
1997 as a revision to WAIS-R.
– Reason = to update norms, extend age range, modify items,
develop higher IQ “ceiling” and “Floor”, decrease reliance on
timed performance, develop/index factor scores etc.
• WAIS - IV = released in 2008, composed of 10 core subtests
and five supplemental subtests, with the 10 core subtests
comprising the Full Scale IQ

7. Forms of the Test
Wechsler Intelligence Scale for Children
(WISC) - Four Editions:
– WISC – 1949, WISC-R 1974, WISC
III 1991, WISC IV 2003 & WISC V
2014,
– 6-16 yrs
– Wechsler Intelligence Scale for
Children (WISC)- developed for
assessing children between 0
and 6 years. Was revised in 1974
– WISC-R.
– WISC-R = was standardized on a
new sample that was more
accurately representative.
• (WISC- III)- Developed 1991, revision
of WISC.
– Major Change = inclusion of four
factor/index scores = Verbal
Compensation, Perpetual
organization, Freedom from
Distractibility, and Processing
speed.
– More reliability and
standardization on 2,200 children
between 6 and 16 years.
• (WISC-IV)
– General cognitive abilities: general
problem-solving/reasoning skills
(verbal, nonverbal, and visual
domains)
– Working memory and processing
speed

8. Forms of the Test
Wechsler Preschool and Primary Scale of Intelligence (4-6yrs)
• Wechsler Preschool and Primary Scale of Intelligence (WPPSI) – A
downward extension of WISC, Developed in 1967.
– In response to an increasing need for the assessment of preschoolers.
– Wechsler Preschool and Primary Scale of Intelligence- Revised (WPPSI
- R) = A revision of WPPSI in 1989.
– expanded the age range to 3–7 years 3 months and introduced a new
subtest, Object Assembly.
• (WPPSI - III)
– Additional subtests to enhance the measurement of Fluid Reasoning.
(Matrix Reasoning, Picture Concepts, Word Reasoning and Measures
of Processing Speed)
• (WPPSI - IV)
– Working Memory subtests added (Picture Memory and Bug Search)
– Processing Speed subtests added ( Bug Search, Animal Coding, and
Cancellation)
• provides Verbal and Performance IQ scores as well as a Full Scale IQ score

9. Test Description (WAIS)
• The WAIS-III is composed of 14 subtests.
• Eleven of the subtests produce the three summary scores of Verbal
IQ, Performance IQ, and Full Scale IQ.
• The verbal subtests include:
– Vocabulary, Similarities, Arithmetic, Digit Span, Information, and
Comprehension. The performance subtests include Picture
Completion, Digit Symbol (Coding), Block Design, Matrix Reasoning,
and Picture Arrangement.
• Two additional subtests: Letter–Number Sequencing and Symbol
Search, are supplemental and included in index scores.
• The index scores :
– Verbal Comprehension (Vocabulary, Similarities, and Information),
– Perceptual Organization (Picture Completion, Block Design, and
Matrix Reasoning),
– Working Memory (Arithmetic, Digit Span, and Letter–Number
Sequencing),
– Processing Speed (Digit Symbol and Symbol Search)

10. Test Description (WISC)
• Generates a Full Scale IQ which represents a
child's general intellectual ability.
• Provides five primary index scores
– Verbal Comprehension Index
– Visual Spatial Index
– Fluid Reasoning Index
– Working Memory Index
– Processing Speed Index

11. Test Duration
• Administration of the
11 subtests approx. 75
mins
– range of 60 to 90 min.
• The time needed to
administer the 13
subtests required to
generate all of the
summary and index
scores is 80 min
– range of 65 to 95 min

12. What it measures/ How it’s used
• Three tests were developed:
– The Wechsler Adult Intelligence Scale
(WAIS)
– Wechsler Intelligence Scale for
Children (WISC)
– Wechsler Preschool and Primary Scale
of intelligence (WPPSI)
• Measures intellectual performance
through observation of personality
in various settings
• Measures a full scale IQ (an
individual's complete cognitive
capacity – verbal and performance)
• Measures several variables
• academic achievement,
• occupational performance etc.

13. What it measures/ How it’s used
• WAIS and WISC provide information on an
individual’s cognitive strengths and weaknesses.
• Helps also check for cognitive changes
– Recovery following after surgery
• Provides clinicians, researchers and educators
with baseline measures on determining the
degree of change in them over time.
– evaluate the effectiveness of an educational
programme
– evaluate changing abilities of a person.

14. What it measures/ How it’s used
• Wechsler scales are scored administered and
scored in a similar way
• Each test has two batteries of subtests grouped
into two general areas:
– Verbal scales – measure general knowledge,
language, reasoning and memory
– Performance scales - measure spatial, sequencing and
problem-solving skills.
• Trained examiners use a set of complex test
materials, test takes approx. 90mins. Raw scores
are converted into standard scores.

15. Intelligence Quotient (IQ)
• “Intelligence” Is an individual's ability to adapt and
constructively solve problems in the environment.
• IQ originally developed by Lewis Terman (1916),
proposed this scale for classifying IQ scores:
– Over 140 :Genius or near genius
– 120-140 : Very superior intelligence
– 110-119:Superior intelligence
– 90-109: Normal or average intelligence
*MA is the mental age
*CA is the chronological

16. IQ Classifications.
WAIS:
• 130+ Very Superior
• 120–129 Superior
• 110–119 High Average
• 90–109 Average
• 80–89 Low Average
• 70–79 Borderline
• 69- Extremely Low
WISC:
• 130 + Extremely High
• 120–129 Very High
• 110–119 High Average
• 90–109 Average
• 80–89 Low Average
• 70–79 Very Low
• 69- Extremely Low

17. Average adult IQ vs. real-life
accomplishments
Accomplishment IQ
• MDs, JDs, and PhDs 125
• College graduates 112
• 1–3 years of college 104 - 110
• Clerical and sales workers 100–105
• High school graduates, skilled 97-100
• 1–3 years of high school 90-95
• Semi-skilled workers 90–95
• Elementary school graduates 90
• Elementary school dropouts 80–85
• Have 50/50 chance of reaching high school 75

18. Assets
• Extensive history of
continuous evaluation.
• Easy to administer with clear
guidelines that limit the
possibility of error.
• WAIS-III and WISC-III both
normed and WAIS-III is co-
normed with the WMS-III
• Has a very extensive
population range.
• Great accuracy in predicting
academic and occupational
performance.
• It is possible to gain
considerable information on
cognitive strengths and
weaknesses.
• Very useful in tracking
cognitive changes over time or
after injury/ illness. In
individuals and various
populations.
• Reveals important personality
and clinical variables.

19. Limitations
• Reductionist interpretations of
test scores label and stereotype.
• Very limited capacity in predicting
non-academic activity.
• They measure present level
functioning so can only be used
to make short term predictions.
• Emphasizing convergent,
analytical and scientific modes of
thought.
• Focus on the outcome of
cognition rather than the process
• Limited ability in assessing
minority groups.
• The meaning of some of the
subset scores is still not well
understood
• A degree of subjectivity when
scoring
• Complexities in calculating scores
creates potential for errors
• Not much change has been made
to the tests despite
advancements in theories of
intelligence

20. General Uses
• These tests are used not only as intelligence tests, but as a
clinical tools
• Used as part of an assessment to diagnose ADHD/ADD and
learning disabilities
• Can be used to show discrepancies between a child's
intelligence and his/her performance at school
• Can be used as part of an assessment battery to identify
intellectual giftedness/ cognitive strengths and weaknesses
• To predict future academic achievement
• Contribute information concerning a child's developmental
and psychological well-being
– Very high/ low scores may suggest contributing factors for
adjustment difficulties in social contexts

21. Wechsler Memory Scale

22. Introduction
• Individually administered, composite batteries
designed to understand the various
components of a person’s memory better.
• Currently in the third edition WMS-III and
provides full range memory functioning.
• Based on current theories of memory and
plays a pivotal role in cognitive assessment.

23. History and Development
• There are three editions of the WMS, each has
incorporated advances in theoretical
understanding of memory.
• WMS composed of brief procedures on memory
for paired words, simple visual designs, texts and
sequences.
• The WMS-R had significant improvements such as
including age-related norms.
• The WMS-IV effectively addresses issues of
behaviour and brain relationships involved in
memory and learning.

24. Test Description
• The WMS has three primary
indexes:
– Immediate Memory (immediate
recall scores from Logical
Memory, Faces, Verbal Paired
Associates, and Family Pictures)
– General (i.e., delayed) Memory
(Auditory Recognition Delay)
– Working Memory
(Letter/Number Sequencing and
Spatial Span)
• Additional subtests include
Orientation, Word List learning,
and Visual Reproduction

25. Test Duration
• Administration time for primary subtests is 30 to
35 min,
• Administration of all of the supplemental
subtests was estimated to take 15 to 20 min of
actual testing time.
• Together, administration of the complete WMS
should take 45 to 55 min

26. What it measures/ How it’s used
• Used for age group 16-90years. The WMS-IV is
designed to measure different memory functions in a
person. Checks:
– logical memory,
– verbal paired associates,
– visual reproduction,
– spatial addition,
– symbol span,
– design memory
– cognitive screener.
• Tests for conditions such as dementia or mild learning
difficulties.

27. What it measures/ How it’s used
• The index scores focus on
– auditory memory
– visual memory
– visual working memory
– immediate memory
– delayed memory

28. What it measures/ How it’s used
• Gives a Brief Cognitive Status Exam
– helps to assess global cognitive functioning (memory
deficits/ neural, psychiatric, developmental disorders)
• Differentiates clinical groups i.e. dementia vs.
normal memory functioning.
• Can be self administered or by a clinician.
– Brief cognitive assessment test (21-point BCAT-SF) six
item test/ administered in <5mins ,
– client is asked to perform simple tasks e.g. show
orientation to time, incidental recall, mental control
etc.
– The test information is presented both verbally and
visually.

29. Assets
• Working visual and auditory memory indices are
distinct and measurable.
• The original WMs was quite short (15 mins)
• The complexity of the WMS-III allows it to
measure a wide range of memory functions.
• Norming of WMS-III with WAIS- III and it’s
superior standardization
• Mostly has clear guidelines on scoring and
administration.

30. Limitations
• Some of the indices are redundant (general and
immediate memory indices)
• WMS-R and WMS-III take very long to administer
(45- 100 minutes). Sometimes practitioners use
only subsets introducing a probability of error.
• High degree of cultural loading in Logical memory
subset I and II.
• Lack of guidelines on how to administer Logical
memory subsets may lead to variations that
affect scores.