Module 6: Tests of intelligence and their Applications

Question 1

Stanford-Binet – Fifth Edition

Answer 1

• Published in 2003
• Now on 5th edition
• Span’s age 2 to 85 years.
• Better than spearman model.
• Based on the CHC model of cognitive functioning
• Derivation of Full-Scale IQ that presumably reflects g.
• Plus, five main factors which m = 100 and a SD=15.

Check notes

Question 2

Psychometric Properties

Stanford-Binet

Answer 2

Norms based on a representative sample.

o Equal chance of being in norm group.

o More people the better.
 4800 individuals from age 2 to 85 years; stratified by gender, ethnicity, region and education.

• Good reliability: coefficients for FSIQ are either .97 or .98 for each of the 23 age ranges.
• Well established validity: FSIQs correlate in the low to mid .8’s with other established measures of intelligence, including Wechsler Scales.

Question 3

Practical and Interpretive Considerations

Stanford-Binet

Answer 3

• Same test used for both children and adults.
• Low-end items for measurement of low functioning.
o Useful for testing kids with intelligence issues.
• Extensive high-end items for measurement of gifted performance.
o Good for testing gifted kids.
• Better than Weschler for those with difficulties/disabilities.
• Better for those that are gifted.
• Better to say the category name and not put the actual score. Say low average instead of 87.
• Use the category name instead of number score.

Question 4

Intelligence Scales:

Answer 4

• Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV)
• Wechsler Intelligence Scale for Children, 5th Edition (WISC-V)
• Wechsler Preschool and Primary Scale of Intelligence, 4th Edition (WPPSI-IV).

Abbreviated version
• Wechsler Abbreviated Scale of Intelligence, 2nd Edition (WASI-II)
o Brief screening battery
Memory Scales
• Wechsler Memory Scale, 4th Edition (WMS-IV)
Academic achievement
• Wechsler Individual Achievement Test, 3rd Edition, (WIAT-III)

Question 5

Wechsler Scales: Common Features:

Answer 5

• All scales from the Wechsler family of intelligence tests share common features.
• Core subtests: A subtest must be administered to obtain a composite score.
• Optional or Supplemental Subtests: administered to provide additional clinical information or extend the number of abilities/processes sampled.
• NB: Supplemental subtests can be used as replacements for Core subtests under certain rules).

Question 6

Wechsler Adult Intelligence Scale - Structure

Answer 6

• Currently in 4th edition
• Used to assess intellectual ability in adults; also for assessing psycho-educational disability and organic dysfunction.
• Mostly widely used for both applied and research purposes.
• Originally published as the Wechsler-Bellevue intelligence scale in 1939.
• It is an individually administered battery has 10 cope subsets (for composite score), has 5 supplementally subtests to provided additional psych info. It takes 67min for 10 core subtests.

Question 7

WAIS-IV Structure

Answer 7

•FSIQ:
o Verbal Comprehension Index VCI
	Vocabulary
	Similarities 
	Information 
•                   Comprehension 
o Woking Memory Index WMI
	Arithmetic 
	Digit Span
•	             Letter-Number Sequencing 
o Perceptual reasoning Index PRI
	Block design 
	Matrix reasoning 
	Visual puzzles 
•	          Picture completion 
•	          Figure weights 
oProcessing Speed Index PSI
	Coding 
	Symbol search 
•	         Cancellation 

See notes

Question 8

Verbal Comprehension Index (VCI)

Answer 8

• Crystallised knowledge is the background. (Acquired knowledge and application of knowledge)
• Application of verbal skills and information to the solution of new problems.
• Ability to process verbal information.
• Ability to think with words.
• Cognitive flexibility (including the ability to shift mental operations.)

Question 9

VCI Subtests:

Answer 9

Similarities (SIMS): Client is read two words aloud and asked to explain how they are “alike’

• Verbal concept formation and reasoning.
• Abstract reasoning.
• Associative and categorical thinking.

Vocabulary (VOCAB):
• Client is shown (in stimulus book) and read aloud a series of words and is asked to provide a definition of those words (what do they mean?)
o Work knowledge and verbal concept formation.
o Fund of knowledge.
o Learning ability.
o Auditory comprehension and verbal expression.

Information (INF)
•Client asked a series of general knowledge questions.
o Ability to acquire, retain, and retrieve general factual knowledge.
o Long term memory.
• No demand of reasoning
• Not just stuff you have learnt in school
• More fluid intelligence.

Question 10

Perceptual Reasoning Index (PRI)

Answer 10

• Ability to think in terms of visual images and manipulate them with fluency.
• Cognitive flexibility (including the ability to shift mental operations.)
• Ability to interpret or organize visually perceived material within a time limit.
• Ability to form abstract concepts and relationships without use of words.
o Fluid: independent from analogies from the past.
o Visual perceptual abilities.

Question 11

PRI Subtests:

Answer 11

• Block design:
o Clint shown a series of 2-dimesional images in stimulus book and asked to recreate the pattern with blocks (also a timed task).
 Ability to analyse and synthesis abstract visual stimuli.

•Matrix Reasoning:
o The client is shown a series of visual patterns with one piece missing. They are required to select from the five options, the images that completes the patter.
 Fluid intelligence.
 Classification and spatial ability.
 Knowledge of part-whole relationships.
 Perceptual organization.

•Visual Puzzles:
o Client is shown a completed puzzle, and is asked to select the 3 pieces from a selection of 6 make that puzzle,
 Ability to analyse and synthesize abstract stimuli.
 Visual perception
 Spatial visualization and manipulation (mental rotation.)

Question 12

Working Memory Index (WMI)

Answer 12

• Short-term memory 
• The ability to sustain attention.
• Numerical ability. 
• Encoding ability. 
• Auditory processing skills.
• Cognitive flexibility (including the ability to shift mental operations).
• Ability to self-monitor.
o	Hold material in mind while manipulating that information. 
o	Higher order processes. 
o	E.g., maintain focus. 
o	Analogy: a general manager.

Question 13

WMI Subtests

Answer 13

• Digit Span:
o Client is read a series of numbers (of increasing length) and required to repeat the numbers in differing ways:
o Forward: repeat numbers in the same sequence they were read
o Backward: repeat numbers on the reverse sequence to how they were read,
o Sequencing: repeat numbers in numerical order.
 Forward: Short term memory (not working memory) basic attention, encoding, auditory processing.
 Backward/Sequencing: working memory, transformation of information, mental manipulation, mental alertness.

• Arithmetic:
o	Client read aloud (with no visual reminders) a series of mathematical problems. The mathematical procedures involved are not complex as the task designed to tap working memory.
	        Mental manipulation 
	        Concentration
	        Attention
	        Numerical reasoning ability
	       Quantitative knowledge.

Question 14

Processing Speed Index (PSI):

Answer 14

• Perceptual discrimination.
• Speed of mental operation
• Psychomotor speed
• Concentration
• Short-term visual memory
• Visual-motor coordination

Question 15

PSI Subtests:

Answer 15

• Coding:
o Client uses a key that pairs various symbols with numbers to draw the correct sequence of symbols in an array of random numbers (this task is timed and the client is required to complete as many items as they can in 2 minutes).
 Mental processing speed
 Speed and accuracy of grapho-motor-processing.
 Sequencing ability.

•Symbol search:
o Client is asked to identify whether a target design (symbol) is present in a series of designs or symbols. They simply draw a line through the correct box that indicates wither ‘yes’ or ‘no’. (this task is times and clients are required to complete as many items as they can in 2 minutes.)
 Mental process speed.
 Speed of visual search

• Low score may be because of graphite motor processing, or visual elements.

Question 16

WAIS-IV Hierarchy of Interpretation:

Answer 16

• Analysis and interpretation proceed from the most reliable measures on the test.
• Begin with FSIQ (level 1) and proceed down the 5 subsequent level of analysis.
1. FSIQ
2. Factor Indexes (VCI, PRI, WMI, PSI)
3. Subset deviations within the composite scores.
4. Inter-subtest score comparisons
5. Intra-subtest Score comparisons
6. Qualitative analysis
• Hierarchical interpretive strategy or successive level interpretation for the 6 dot points. Increasing less reliable going downwards in the list.
• Factor index scores are always in a psych report.
• Levels 3-6 may not be in a psych report. Scores may not add anything meaningful.

Question 17

General Principles of Interpretation

Answer 17

Consider the accuracy and reliability of a given composite score. Does the score reflect the global ability it is designed to measure?
Interpret and comment on scores in two ways:
• Normative Comparison: How has the person performed compared to others of similar age?
• Personal Comparison (strengths and weaknesses): How does the client’s score in one cognitive domain compare to their performance in other domains?
• Personal scores (ipsative): comparing scores against themselves. Used to asses’ strengths and weaknesses.

Question 18

Principle 1: Are composite scores unitary?

Answer 18

Composite score: are designed to globally represent performance across a range of subtests that all measure similar abilities.
However, the subtests are not identical, so they also have unique abilities that they measure.
A composite score is only useful if it describes a unitary ability (i.e., all the subtest scores that make up that composite ar relatively consistent.)

Question 19

Principle 2: Describing client performance:

Answer 19

see notes

Question 20

Principle 3: An integrative Approach:

Answer 20

• Test interpretation requires an integrative approach that draws upon multiple sources of information. This includes:
o Integration of information from several different subtests and or/
o Combining test score information with other information such as observation on behaviour on clinical history information.
• Never interpret a single subtest score on its own.
• Is the index score unitary or not?
• Working memory index and processing speed are unitary.
• The three subtests for perceptual reasoning or comprehension index are not unitary.
• Maybe the client was nervous, silly errors? Score may not relate to ability.

Question 21

Level 1 Interpretation:

Answer 21

Full Scale Intelligence Quotient (FSIQ):
• Commence by interpreting the FSIQ and make way down the hierarchy.
• FSIQ is the most reliable estimate of intelligence (.98 split half) and will give an estimate of a person’s overall level of intellectual functioning.
• In psychological report, describe the clients FSIQ performance in terms of descriptive categories associated with the full range of confidence interval.
o Overall intellectual functioning.
o Initially report normative findings.
o Never the actual score, except for reports for children if they are school based reports. We need percentile rank numbers, teachers understand. Never use a number.

Question 22

Level 2 Interpretation:

Answer 22

• We must always go beyond interpretation of the FSIQ to consider Primary Index Scores.
• At Level 2, first step is to use primary index scores to determine if the FSIQ is unitary, i.e., is the FSIQ a good representation of the client’s overall functioning?
• Rule of thumb: classify the FSIQ as non-unitary if the difference between the highest and lowest primary index scores is greater than 22 points.
• In the report we would describe performance of the FSIQ is used as a reference point. It is unitary you would report. However, if it was not unitary: make a comment that it is not a meaningful overall interpretation of the client. We would need to look at other levels.

Question 23

Primary Index Scores (VCI, PRI, WMI, PSI):

Answer 23

• Useful to characterise your client’s strengths and weaknesses.
• More reliable than subtests.
• In analysing Primary Index scores, need to consider:
o Normative comparison of performance.
o Personal strengths and weaknesses (i.e., comparison between indexes); a discrepancy between index scores of more than 9 points is likely to indicate a significant difference.
• In a psychological report, you would interpret each of the Primary Index Scores (often in separate paragraphs but will vary on a case-by-case basis).
• Complex stats to determine strength and weakness. – for this course only look at difference of 9 points.

Question 24

Level 3: Subtest deviations within the composite scores:

Answer 24

• Rule of thumb: if the difference between highest and lowest subtest within a given index is greater than 5 points, the index is considered non-unitary, and you would not interpret or report this index scre.
• Even if they index is unitary, you may still want to focus on differences (e.g., block design lower than other PRI subtests because block design is a times task.

Question 25

Level 4 Interpretations: Inter-subtest score comparisons

Answer 25

• Involves comparing and grouping subtests to arrive at meaningful conclusions.
• Consider with subtests have aspects in common, even if they are from different indices (e.g., both similarities and matrix reasoning measure abstract reasoning)

Question 26

Level 5 Interpretations: Intra-subtest Score comparisons

Answer 26

• Involves within subtest comparisons e.g., comparison of digit span forward (short-term memory) with digit span backward (working memory).
• Use with caution.

Question 27

Level 6 Interpretations: Qualitative analysis

Answer 27

• Consider the way a client approached specific subtests or tasks (e.g., were they impulsive, logical or methodical in their approach?)