Wechsler Scales 10/15/18
Where Did Wechsler Get His Ideas
(They weren't original) He basically "lifted" his subtests from other scales
Where Did Wechsler Get His Ideas (OLD)
(They weren't original) He basically "lifted" his subtests from other scales Block Design derived from Kohs Block Design Tests (he just made them red & white and not blue & yellow) Coding derived from Coding on Army Beta Intelligence Test (identical) Vocabulary derived from Stanford-Binet Intelligence Test Mazes derived from Porteus Maze Test Matrix Reasoning derived from Raven Progressive Matrices Test Picture Completion derived from Stanford-Binet Intelligence Test Comprehension derived from Stanford-Binet Intelligence Test Etc.
Name the subscales (subtests and the constructs that they measure) of the WAIS-IV
(supplements showed in parentheses) Verbal Comprehension Vocabulary Similarities Information (Comprehension) Perceptual Reasoning Block Design Matrix Reasoning Visual Puzzles (Picture Completion) Figure Weights Processing Speed Symbol Search Coding (Cancellation) Working Memory Digit Span Arithmetic (Letter-Number Sequencing)
If you could pick only 2 for a short-form, which 2 would it be? Why?
-vocabulary -block design they are best measures of g - highly correlated vocab(.83) block design(.70)
If you could pick only two scales from the WAIS-IV to administer, which 2 should you pick? Why?
-vocabulary -block design (or matrix reasoning) they are best measures of g
WISC-V - which subtests are needed to get FSIQ
1) Vocabulary 2) Similarities 3) Matrix Reasoning 4) Figure Weights 5) Digit Span 6) Coding 7) Block Design Full Scale IQ based on 7 subtests (noted by --) Verbal Comprehension --Similarities --Vocabulary Comprehension Information Fluid Reasoning --Matrix Reasoning --Figure Weights Picture Completion Working Memory --Digit Span Arithmetic Letter-Number Sequencing Processing Speed --Coding Symbol Search Cancellation Visual Spatial --Block Design Visual Puzzles
"Evolutionary" History of Wechsler Scales
1939: Wechsler-Bellevue Scale of Intelligence (Developed in reaction to 1937 Stanford Binet) 1942 Wechsler-Bellevue Scale of Intelligence-Revised 1949: Wechsler Intelligence Scale for Children 1955: Wechsler Adult Intelligence Scale 1967: Wechsler Preschool and Primary Scale of Intelligence 1974: Wechsler Intelligence Scale for Children-Revised 1981: Wechsler Adult Intelligence Scale-Revised (Wechsler dies this year) 1989: Wechsler Preschool and Primary Scale of Intelligence-II (There is a WPPSI 3 that isn't listed here) 1991: Wechsler Intelligence Scale for Children-III 1997: Wechsler Adult Intelligence Scale-III 2003: Wechsler Intelligence Scale for Children-IV 2004: Wechsler Adult Intelligence Scale-IV 2014: Wechsler Intelligence Scale for Children-V
Background of Profile Analysis (scatter analysis) 2 major purposes and other info
2 Major Purposes To discriminate low-average-high performing individuals Identify cognitive strengths & weaknesses 10 subtests yield 180 combinations comparing 2 subtests at a time n!/n!-r! or 10!/8!2!=180 Comparing 2 subtests results in comparing difference scores -Difference score are always less reliable than scores used to calculate difference- Some think subtest profiles can be used to diagnose different conditions: 1) ACID Profile to identify specific learning disabilities Low scores on Arithmetic-Coding-Information-Digit Span 2) SCAD profile to identify attention/deficit hyperactivity disorder Low scores on Similarities-Coding-Arithmetic-Digit Span 3) Learning Disability Index (LDI) Low scores on Information-Vocabulary-Similarities-Comprehension
Profile analysis (scatter analysis) & why it shouldn't be used to dx (OLD)
Base rates of subtest profiles What percent of "normal" population have various subtest profiles? Do any non-learning disabled children have ACID profiles? Do any non-AHDHD children have SCAD profiles? Do any non-learning disabled children have LDI profiles? Answer to all 3 questions is YES! Do all LD children have ACID profiles? -NO Do all ADHD children have SCAD profiles? NO Do all LD children have LDI profiles? NO So, can you use various subtest profiles to diagnose specific conditions? NO! because these profiles have relatively high base rates in the "normal" population and not all LD or ADHD children have these profiles In fact, the majority of LD and AHDH children do NOT have ACID and SCAD profiles In short, these are not diagnostic of these conditions
What are 3 ways to measure Subtest Scatter Analysis
Determination of Scatter (3 ways to measure): 1) Lowest - Highest subtest scores 2) Comparisons to standardization sample 3) Ipsative analysis (deviation of subtest scores from average subtest score) Example of Subtest Scatter Analysis S-4 (W) Highest -Lowest = 10-3=7 V-10 C-9 BD-3 (W) PC-8 MR-4 (W) (W) = weakness (not a good idea to do a scatter analysis)
VIQ and PIQ were removed after the WAIS-III, what were they replaced with on the WAIS-IV?
General Ability Index 3 Verbal Comprehension Subtests (VIQ) 3 Perceptual Reasoning Subtests (PIQ) (This could be a 6 subtest short form)
More on Cognitive Proficiency Index
High Scores High degree of cognitive efficiency for manipulating & rapidly processing information Low Scores Visual or auditory processing deficits (Specific Learning Disability?) Inattention (ADHD?) Distractibility Visual Motor Difficulties Limited Working Memory Low Cognitive Ability (ID?)
Successive Five-Level Interpretation WAIS-IV/WISC-V
Level I: Interpret Full Scale IQ Determine percentile rankings & IQ classification Level II: Interpret Index Scores & CHC Groupings Interpret cognitive strengths & weaknesses normatively Do not interpret strengths & weaknesses ipsatively (contrary to our textbook) Index scores (Verbal Comprehension, Perceptual Reasoning (Visual Spatial/Fluid Reasoning, Working Memory, & Processing Speed CHC Cluster groupings (Fluid Reasoning, etc.—see p. 162 of textbook) Level III: Interpret subtest variability Level IV: Qualitative/Process Analysis Level V: Analyze intrasubtest variability
General Strategies for Wechsler Interpretation
Make initial general statement (e.g., "excellent verbal abilities with VCI score of 125 which is in the 95th percentile") Elaborate by listing subcomponents of ability (e.g., "good fund of general information with an Information score of 14, good level of word knowledge with a Vocabulary score of 15") Give qualitative description of test responses ("could easily define difficult words, accurately described similarities between 2 related objects or ideas, was able to recall accomplishments of famous people") Give qualitative description of history/behavioral observations (e.g., "quickly, concisely, and accurately answered questions") Provide implications for everyday life (e.g.,"will be able to easily understand complex conversations, would do well in verbally oriented occupations")
What pattern do you see in the fair measures of g?
Nonverbal intelligence/ability
Profile analysis (scatter analysis) & why it shouldn't be used to dx
Not everyone who has an ACID, SCAD, or LDI profile has the condition that it's meant to diagnose Not all people with ADHD score on SCAD profiles // Not all people with Learning Disability score on ACID/LDI profiles These profiles have high base rates in the normative population/not all people with ADHD or LD have these profiles (in fact, the majority do not)
WPPSI-IV older test version
Older Test Battery (4yr-7yr7mo) Verbal Comprehension Information Similarities (Vocabulary) (Comprehension) Visual Spatial Block Design (Object Assembly) Fluid Reasoning Matrix Reasoning (Picture Concepts) Working Memory Picture Memory (Zoo Locations) Processing Speed Bug Search (Cancellation) (Animal Coding)
How was perceptual reasoning changed for the WISC-5?
Perceptual reasoning - split it into fluid reasoning and visual spatial reasoning
Ancillary Index Scales
Quantitative Reasoning Figure Weights Arithmetic Auditory Working Memory Digit Span Letter-Number Sequencing Nonverbal Block Design Visual Puzzles Matrix Reasoning Figure Weights Picture Span Coding Note: This is basically Performance IQ General Ability Similarities Vocabulary Block Design Matrix Reasoning Figure Weights Note: This is basically a 5-subtest short form Cognitive Proficiency Digit Span Picture Span Coding Symbol Search Note: 2 subtests from Working Memory & 2 subtests from Processing Speed
Basic Steps to Interpretation
Report and Analyze Full Scale IQ Report and Describe Primary Index Scores (VC, VS, FR, PS, WM) Evaluate Index-Level Strengths and Weaknesses Normatively Ipsatively Example: Full Scale IQ-97 (42%ile) Verbal Comprehension-88 (21st %ile) Visual Spatial-110 (75th %ile) Fluid Reasoning- 108 (70th %ile) Processing Speed-87 (19th %ile) Working Memory-92 (30th %ile)
Profile analysis (scatter analysis) to dx conditions
Some think subtest profiles can be used to diagnose different conditions: 1) ACID Profile to identify specific learning disabilities Low scores on Arithmetic-Coding-Information-Digit Span 2) SCAD profile to identify attention/deficit hyperactivity disorder Low scores on Similarities-Coding-Arithmetic-Digit Span 3) Learning Disability Index (LDI) Low scores on Information-Vocabulary-Similarities-Comprehension
What greatly influenced Wechsler's assessment design?
Spearman's g g = general intelligence or g factor
What was the original Wechsler scale a response to?
Stanford-Binet IQ test
Wechsler Scales Some Background OLD
Theory and Structure Received Ph.D. from Columbia University in 1925 (major professor Robert Woodworth) Influenced greatly by Spearman's g Defined intelligence as a "global ability" Intelligence conceptualized as specific abilities related to g David Wechsler was chief psychologist at Bellevue Psychiatric Hospital in New York City (1932-1967) Scales more clinically derived than theoretically derived (and they were not original) David Wechsler died on May 2, 1981 (same year WAIS-R was published) Later iterations of scales influenced by more recent theoretical advances (CHC theory) Working Memory Processing Speed Visual/Spatial Reasoning Fluid and Crystallized Intelligence Recent versions provide factor index scores above & beyond VIQ & PIQ Recent iterations validated against other recent IQ tests (r =.80-.90) Stanford-Binet V Woodcock-Johnson Test of Cognitive Abilities Differential Abilities Scale Kaufman Adolescent and Adult Intelligence Test
What are the subscales/constructs of the WISC-5?
VC: Verbal Comprehension FR: Fluid Reasoning WM: Working Memory PS: Processing Speed VS: Visual Spatial Perceptual reasoning - split it into fluid reasoning and visual spatial reasoning
Wechsler Scales WAIS-IV - other notes
VIQ & PIQ eliminated from WAIS-III General Ability Index 3 Verbal Comprehension Subtests (VIQ) 3 Perceptual Reasoning Subtests (PIQ) (This could be a 6 subtest short form) If you could pick only 2 for a short-form, which 2 would it be? Why? -vocabulary -block design they are best measures of g
WISC-V constructs measured
Verbal Comprehension (crystallized intelligence) Visual Spatial Fluid Reasoning (fluid intelligence) Working Memory Processing Speed
What constructs are measured by the WISC-V?
Verbal Comprehension (crystallized intelligence) Visual Spatial Fluid Reasoning (fluid intelligence) Working Memory Processing Speed
What are VIQ and PIQ?
Verbal IQ and Performance IQ
What pattern do you see in the good measures of g?
Verbal intelligence/ability is a good measure of g
Some Thought Questions
What pattern do you see in the good measures of g? verbal If you wanted to construct a short form verbal measure of intelligence, what subtests would you include in it? vocab, block design, matrix reasoning Why? What pattern do you see in the fair measures of g? nonverbal If you wanted to construct a short form nonverbal measure of intelligence, what subtests would you include in it? Why? Why do you think Cancellation is such a poor measure of g? doesn't measure intelligence, has more to do with speed
WPPSI-IV younger test version scales/ages
Younger Test Battery (range 2yr 6mo - 3yr 11mo) Verbal Comprehension Receptive Vocabulary Information (Picture Naming) Visual Spatial Block Design Object Assembly Working Memory Picture Memory Zoo Locations
How did Wechsler conceptualize intelligence?
as specific abilities related to g (general intelligence)
Were Wechsler scales clinically derived or theoretically derived?
clinically derived
types of intelligence
crystallized - primarily verbal -tends to increase with age, highly correlated with higher levels of education fluid - primarily non-verbal -goes down after age 25
Where did Wechsler get idea for Coding
derived from Coding on Army Beta Intelligence Test (identical)
Where did Wechsler get idea for Block Design
derived from Kohs Block Design Tests (he just made them red & white and not blue & yellow)
Where did Wechsler get idea for Mazes
derived from Porteus Maze Test
Where did Wechsler get idea for Matrix Reasoning
derived from Raven Progressive Matrices Test
Where did Wechsler get idea for Picture completion
derived from Stanford-Binet Intelligence Test
Where did Wechsler get idea for Vocabulary
derived from Stanford-Binet Intelligence Test
Where did Wechsler get idea for comprehension
derived from Stanford-Binet Intelligence Test
Why is Cancellation is such a poor measure of g?
doesn't measure intelligence, has more to do with speed (according to Dr. G)
Subtests as Measure of g WAIS-IV (know at least 1 that is good/fair/poor)
g = general intelligence best measures of g are verbal best on test - vocabulary Good Measures of g Vocabulary (.83) Information (.81) Similarities (.81) Arithmetic (.77) Word Reasoning (.73) Comprehension (.73) Fair Measures of g Block Design (.70) Matrix Reasoning (.70) Picture Completion (.66) Letter-Number Sequencing (.66) Symbol Search (.61) Picture Concepts (.61) Digit Span (.57) Coding (.51) Poor Measures of g Cancellation (.27)
How did Wechsler define intelligence?
global ability
How were later iterations of Wechsler scales different from earlier versions in terms of how they were derived?
later versions more influenced by theoretical advances (Cattell - Horn - Carroll or CHC theory) contrasts with earlier versions that were clinically (not theoretically) derived
What is fluid intelligence?
primarily non-verbal -goes down after age 25
What is crystallized intelligence?
primarily verbal -tends to increase with age, highly correlated with higher levels of education
How were recent versions of Wechsler scales validated and what was their rating?
validated against other IQ tests r = .80-.90
