2- Weschler Flashcards
1- History of these tests recap
Binet & Simon
Conceived a test to identify
children who needed special
schooling
Came up with the concept of
“mental age”, later replaced by
“quotient”
Terman & Stanford-Binet IQ test
Standardized the test with >1000
children ages 4 to 14
Used schools in a “representative
area”, so the sample population
was much more representative of
the general population.
David Weschler
Creates a test for adults and
children (WAIS, WISC)
WAIS= Weschler adult intelligence scale
WISC= Weschler intelligence scale for children
2- WAIS 4 overview
1- Verbal Comprehension Index Scale
Core subtests:
1.1 Similarities
1.2 Vocabulary
1.3 Information
*Supplemental subtest:
Comprehension
2- Perceptual Reasoning Index Scale
Core subtests:
2.1 Block Design
2.2 Matrix Reasoning
2.3 Visual Puzzles
*Supplemental subtests:
Figure Weights (16-69 only)
Picture Completion
3- Working Memory Index Scale
Core subtests:
3.1 Digit Span
3.2 Arithmetic
*Supplemental subtest:
Letter-Number Sequencing (16-69 only)
4- Processing Speed Index Scale
Core subtests:
4.1 Symbol Search
4.2 Coding
*Supplemental subtest:
Cancellation (16-69 only)
3- Verbal Comprehension Index
Core subtests:
1.1 Similarities (fluid): * What do these two words have in common?
1.2 Vocabulary (crystallized): * How would you define/describe this word?
1.3 Information (crystallized): * Simple to difficult fact questions
*Supplemental subtest:
Comprehension (fluid)
Measures what?
One’s ability to comprehend verbal
stimuli, reason with semantic material and communicate thoughts and ideas with words.
Vocabulary and Information subtests = crystalized knowledge (which is defined as the depth of a person’s acquired knowledge of a culture and the effective application of this knowledge).
Similarities and Comprehension = fluid because they involve direct
reasoning with crystalized words.
4- Perceptual Reasoning Index
Core subtests:
2.1 Block Design (perceptual organization): ”Make this design with 3d blocks
2.2 Matrix Reasoning (fluid): “Which of these best completes the picture?”
2.3 Visual Puzzles (perceptual organization): “Using the top image, which of these bottom images could you make?”
*Supplemental subtests:
Figure Weights (16-69 only) (fluid): like a balance
Picture Completion
Measures what?
* Fluid reasoning, as well as perceptual organizational skills and visuoconstruction.
* Matrix Reasoning and Figure Weights = fluid reasoning.
* Bloc Design and Visual Puzzles are more related to perceptual organisational skills.
5- Working Memory Index
Core subtests:
3.1 Digit Span: * Repeat a series of numbers backwards, forwards, or in number sequence
-forward
-backwards
3.2 Arithmetic: * Simple to more difficult math problems
*Supplemental subtest:
Letter-Number Sequencing (16-69 only)
-put numbers or letters in chronological order
Measures what?
Attention, concentration and working memory
Ability to hold information in one’s
mind temporarily while performing
some operation or manipulation with information, or engaging in an
interfering task, and then accurately reproducing the updated information or correctly acting on it.
6- Processing Speed Index
Core subtests:
4.1 Symbol Search: * Is the far left symbol in the row?
4.2 Coding: * Translating numbers to symbols
*Supplemental subtest:
Cancellation (16-69 only)
Measures what?
Speed of mental processing, using visual stimuli and graphomotor
skills, and is importantly related to the efficient use of other cognitive abilities.
A weakness in simple visual
scanning and tracking may leave a person less time and mental
energy for the complex task of
understanding new material.
7- Raven Matrices
- In the WAIS, but not the WISC
Puzzle-like test, similar to perceptual reasoning tests
Better face validity than some of the
older IQ tests
Correlates highly with general IQ - Correlates almost as well with Verbal
IQ and Performance IQ - High correlation between logically
very different tests : Is there a g?
Based on analogies : - Example of a Verbal analogy = “Cat is to
purr as dog is to – ” - However, Raven is visual, not verbal
- Hopefully more culturally fair
- Less dependent on literacy and
societal experience.
8- How to interpret WAIS?
The scores on ALL the subtests are correlated
Over the years, the one less correlated with the rest were taken out
- WAIS norms are based on US, English-speaking sample
- Clinicians use it to:
- Measure cognitive potential or dysfunction
- Develop edu/vocational placements or interventions for clients
- Diagnose with specific disorder
- Researchers use it to:
- Measure general cognitive function and understand participants
- Being able to understand test targets and interpret test results will be
important for the exam!!
9- WAIS 4 score interpretation
Main battery
Blocs 45 / 66
Similarities 30 / 36
Digit span 40/ 48
Matrices 23/ 26
Vocabulary 10 / 57
Arithmetic 12/ 22
Symbol search 50 / 60
Visual puzzle 20 / 26
Information 10 / 26
Coding 120 / 135
Supplemental tests (optional)
Letter number sequencing 22 / 30
Figure weights 22 / 27
Comprehension 22 / 36
Cancellation 22 / 72
Picture completion 10 / 24
Measures of Dispertion:
Normal curve
Mean (X)= 100
Standard Deviation (SD)= 15
SEE IMAGE
Qualitative description of IQ scores:
130+ : very superior - 2.2%
120-129: superior - 6.7%
110-119: high average - 16.1%
90-109: average - 50%
80-89: low average - 16.1%
70-79: borderline - 6.7%
69 and below: extremely low - 2.2%
1 – compare to expected average for age
Expected score (norm) vs. your raw score
IQ = Your score VS Mean from
Population (norms)
IQ = Your score VS average score for someone your age
some norms are “corrected”
(adjusted) to gender and education
2 – compare to usual variation of scores
SEE IMAGE
Both groups do not have the
same dispersion of scores
We need the SD of the
population to interpret the raw
score
10- Validity and reliability
VALIDITY
What is validity?
Validity = are you measuring
the things you intend to
measure
How Valid Are IQ tests?
IQ predicts school performance in children and many indexes of success in adulthood.
However, the WAIS does not assess 100%
intelligence: It also assesses other non-intellectual factors
Also impacted by physical and mental state (not enough sleep, dehydrated, dumped last night, caffeine, anxious, don’t want to do it…)
SEE IMAGE OF WHAT VALIDITY IS
RELIABILITY
Reliability = can you get the
same results every time you
test. At different times, with
different ppl.
How reliable are IQ scores ?
Test-retest reliability is good – but not 100% stable from one day to the next. It varies with mood and effort, for instance. Still, its relatively stable.
Inter-rater reliability is good – all of administration and scoring is very much standardized so scores don’t vary depending on the rater.
Confidence Interval WAIS 4 (see image)
11- How stable is IQ over time?
Does early IQ predict young adult IQ ?
(see image and listen to lecture cuz idk)
How stable is IQ, over lifetime?
Is IQ stable with age?
Raw score declines over time
Flynn Effect:
Definition : In most western
societies, IQ gradually rise with
each subsequent age group.
Every year, 16 year olds get
better at the same test
Average gain = 3 IQ points per
decade (1930-1990)
This is why the tests must be
frequently re-standardized
To keep the mean IQ at 100
Not all tests show the exact same
increases in IQ points over time…
??
Raven’s tests and other measures
of Gf show largest increase
- Raven’s +5.69 points
-Wechsler Global IQ +5.2 points
- Performance IQ +7.8 points
- Verbal IQ +4.2 points
Careful !
Comparing longitudinal versus
cross section studies does not
take into account the cohort
effect…. If we really wanted to
prove that this is real, longitudinal
studies are best.
Hypothetical causes…to explain the
increase in IQ points over time
Nutrition
Education
Child rearing practices
Increased exposure to testing
and testing material
Increased familiarity with the
type of exercises tested
Decreased family size
Heterosis
Exposure to artificial light (by
Jensen in “The g Factor”)
More complex visual
environment (shift from verbal
communication to visual and
interactive media)
12- Interpretation of scores
ETHIC AND DEONTOLOGY
KNOWLEDGE ARE ESSENTIAL IN
ORDER TO INTERPRET THESE SCORES
WAIS – Standardization. Where do
these norms come from?
The WAIS-IV was standardized on a sample of 2,200 people in the
United States ranging in age from 16 to 90.
An extension of the standardization has been conducted with 688 Canadians in the same age range.
WAIS 4 norms are ENGLISH only
FRENCH translation not validated since it came out around 2010 The median Full Scale IQ is centered at 100, with a standard
deviation of 15.
In a normal distribution, the IQ range of one standard deviation
above and below the mean (i.e, between 85 and 115) is where
approximately 68% of all adults would fall.
WAIS: what does it tell us?
Clinicians may say : * It measures cognitive potential or neurological
dysfunction, * Helps make educational or vocational placements
decisions, * Helps developing interventions for educational or
vocational settings, * Helps with differential diagnosis: intellectual disability vs
specific learning disorder.
Researchers may say : * It measures general cognitive functioning of your studied
population, * It helps define / understand your participants
Wechsler defined intelligence as a global entity that is composed of qualitatively different abilities, this specific abilities included cognitive abilities,
and other non-intellectual abilities such as drive, persistence, temperament, curiosity and personality.
SEE JAMIE’S ASSESSMENT AT THE END OF THE POWERPOINT - IMPORTANT TO UNDERSTAND HOW TO INTERPRET RESULTS
