- The measurement of ability is one of the largest areas with psychological testing.
- The range of ability tests is immense, from measuring broad concepts like intelligence
to specific concepts like fine motor control.
- The most popular of these ability tests are those that attempt to quantify intelligence.
We will spend the majority of our time talking about intelligence test, specifically the
Wechsler Adult Intelligence Scale.
- The WAIS-III is an individually administered, composite intelligence test in a battery
- It assesses different areas of intellectual ability and creates a situation in which
aspects of personality can be observed.
- The WAIS-III is composed of 14 subtests. Of these 14 subtests, 11 contribute to the 3
different IQ scores:
- 1) An overall IQ or full-scale IQ;
- 2) A Verbal IQ;
- 3) A Performance IQ.
- In addition to these 3 IQ scores, the WAIS-III also provides indices for the following:
- A) Verbal Comprehension;
- B) Perceptual Organization;
- C) Working Memory;
- D) Perceptual Speed.
- The verbal scales assess the individuals competency in the following areas:
- A) The ability to work with abstract symbols;
- B) The amount & degree of benefit a person has garnered from their education;
- C) Memory: verbal ability;
- D) Verbal fluency.
- The verbal scales are generally more vulnerable to cultural influence than the
performance scales. Why?
- If a person scores more than 12 points better on the verbal scales than the performance
subtest, one of the following may be true:
- 1) The person as a high degree of education;
- 2) Psychomotor slowing due to depression;
- 3) The person may have a tendency to overachieve;
- 4) The person may have difficulty working with practical tasks;
- 5) Poor visual-motor integration;
- 6) A slow, deliberate work style. This will produce higher scores of the verbal tests
than the performance tests.
- Who do you think is most vulnerable to a large verbal performance (where verbal
is much larger than performance, called a V > P effect) difference?
- A V P effect is most pronounced in adult, educated (> 12 yrs),
caucasian males with acute lesions (strokes, tumor) in the right hemisphere (often
temporal lobe). Interestingly, persons with right temporal lobe epilepsy often show the
V > P effect.
- This scale tests the following:
- A) Range of general factual knowledge;
- B) Old learning or schooling;
- C) Intellectual curiosity and commitment to collect knowledge;
- D) Awareness of day-to-day world;
- E) Long-term memory.
- This test samples the type of knowledge that an average person with average
opportunities should know. The knowledge is usually based on over-learned material.
- This type of knowledge is very resistant to neurological damage and psychological
disturbance. It is one of the most stable subtests.
- To score well on this test the test taker has generally been exposed to a variety of
environments, has many interests, and has an intact long-term memory.
2. Digit Span:
- A) Immediate recall (rote), both forwards and backwards;
- B) Ability to shift thought patterns (reversibility);
- C) Attention and concentration;
- D) Auditory sequencing.
- This is considered a test of auditory/vocal short-term memory and attention.
- Correct responses are based on a two-step process: 1) The person must accurately encode
the information; 2) The test taker must accurately recall, sequence, and vocalize the
- Can you think of some individuals who may have difficultly with this task?
- Persons who are passive and anxiety-free appear to do best on this test. Scores decrease
significantly if anxiety or tension is present. The combination of scores on digit span,
and the arithmetic and digit symbol/coding subtests are known as the anxiety
- Persons who score well on digit backwards generally reflect persons who are flexible,
have considerable concentration skills, and tolerate stress well.
- Digit span along with digit symbol/coding are the most sensitive subtest for determining
brain damage, intellectual impairments, and learning disabilities.
- In some rare cases, persons score higher on digit backwards than digit forwards! Any
- Some other interesting findings with digit span:
- A) A 5-item discrepancy between digit forward and backward may suggest organic damage.
Especially if digit backward scores are lower than the information and vocabulary
- B) Lowered digit forward is more often associated with left hemisphere lesions, lowered
digit backward with right frontal damage or diffuse brain damage (e.g., the type seen with
- Language development;
- Word knowledge;
- Overall verbal intelligence;
- Language usage and accumulated verbal learning ability;
- Educational background;
- This test tests acquired verbal knowledge, and the ability to easily express many ranges
- Vocabulary is the most reliable verbal subtest (.96).
- Like information, vocabulary is not greatly affected by brain damage or psychological
- Scores generally reflect the nature and level of sophistication of the test takers early
schooling and culture learning. Note, it can be improved by later learning.
- Vocabulary is the most stable (least variable) of all the subtests. As such, it is often
used to indicate a test takers intellectual potential and sometimes to estimate their
premorbid level of function.
- High scores on vocabulary indicate high intelligence. Test takers with high scores often
have wide ranges of interests, have acquired lots of general information, and sometimes
have high achievement needs. Low scores suggest a poor educational background, lower IQ,
impaired development of language (e.g., poor English) and/or poor motivation.
- Computational skills and school learning;
- Auditory memory and sequencing ability;
- Numerical reasoning and numerical manipulation speed;
- Concentration and attention;
- Contact reality and mental alertness;
- Logical reasoning and abstraction;
- The arithmetic subtest requires the following to score well; focused concentration,
basic mathematical skills (usually have them by grade 7-8), and the ability to apply these
- Test takers often find this subtest more challenging and stressful than the other
subtests because it is more demanding and is timed!
- If you are an anxious person, how will your scores be affected? Test examiners often
recognize anxiety and may give second chances with paper-and-pencil and with
no time limit on items. Why?
- Persons who do well here tend to come from high socioeconomic families, are obedient
teacher-oriented students and persons with intellectualizing tendencies. It also shows
alertness, concentration, and good auditory & short-term memory.
- Heres an often used formula: School achievement = Information + Arithmetic.
- Antisocial personalities tend to react rebelliously to this test. Any ideas?
- Low scores suggest poor mathematical reasoning, poor concentration, distractibility, or
poor auditory short-term memory. In addition, poor educational backgrounds can account for
- Demonstration of practical knowledge and social maturity;
- Knowledge of conventional standards of behaviour (e.g., moral codes, social rules and
- Abstract thinking and generalization;
- Social judgment and common sense;
- Awareness and understanding of day-to-day reality.
- Comprehension like the information and vocabulary subtests is partly a test of acquired
knowledge (fairly high correlations among these tests), and is also considered a test
which reflects how well test takers conform to convention, have benefited from cultural
experiences, and if they have developed a conscience.
- Comprehension items require adaptive responses that are efficient to deal with specific
problem. Thus, the test taker not only needs to possess the required information, but also
must use the information and verbally present it in some appropriate way.
- Comprehension scores much lower that scores on information suggest that a test taker may
have difficulty using their knowledge.
- High scores indicate reality awareness, social compliance (or at least the ability to
socially comply), good judgment, and emotionally relevant use of information.
- Low scorers, especially if 4 subscale points below vocabulary, may suggest poor
judgment, impulsiveness, and hostility.
- Logical abstract reasoning;
- Verbal concept formation and conceptual thinking;
- Distinguishing essential and nonessential details;
- The similarities subtest requires that the test taker be aware of the belongingness or
togetherness of objects in the environment. Thus, test takers require the ability to
reason abstractly and to form verbal concepts.
- Inductive reasoning and long-term memory are required since test takers need to move
from particular facts to a more general rules or principles.
- Scores on similarities decrease substantially in persons afflicted with schizophrenia,
persons who are very rigid or inflexible thinkers, persons with senile dementia.
- High scores show good verbal concept formation and good abstract reasoning.
7. Letter-Number Sequencing
This is a new subtest. It is part of the new working memory index.
A series of mixed-up orally presented letters and numbers are given to test takers.
The test taker must reorder and repeat the list by saying the numbers first (in
ascending order) and then the letter in alphabetical order.
Can you see any overlap with some other tests?
Overall the verbal component is assessing the ability to work with abstract symbols,
verbal fluency, and verbal meaning. This component is highly influenced by the
amount and degree a person has received from education. Thus, it is subject to
The Performance Scales
- Overall the scores on the performance scales represent the following:
- A) The degree and quality to which an individual makes nonverbal contact with the
- B) The capacity to integrate perceptual stimuli with purposeful motor behaviour.
- C) The ability to work quickly in concrete situations.
- D) The ability to interpret visuospatial stimuli.
- The performance tests are not as vulnerable to cultural bias as the verbal subtests.
- If a person scores significantly better on the Performance than the Verbal subtests
(i.e., 12 points or greater) what could this mean?
- Superior perceptual organization abilities.
- Very good at working under time constraints.
- A tendency toward low academic achievement (e.g., a doer and not a thinker).
- Greater possibility of acting out (e.g., delinquency).
- Someone for a low SES.
- The presence of a language deficit (e.g., learning disability).
- A possible lesion/tumor in the left hemisphere. Note: P > V discrepancies are not as
reliable as V > P discrepancies. P > V discrepancies mostly occur in adult males
with low educational attainment and lesion in the left posterior frontal lobe.
- Certain populations are also likely to have a P > V discrepancy. These populations
include Native Americans, Hispanics, bilingual persons, and blue-collar workers where
visual-spatial learning is stressed.
1. Picture Completion
- A) Visual recognition and identification (long-term visual memory).
- B) Reality contact; awareness of environmental detail.
- C) Visual conceptual ability (perception of whole to its parts).
- D) Discrimination of essential from nonessential details.
- E) Ability to organize visually organized material.
- Picture complete measures visual concentration and nonverbal general information. It to
some extend depends on the test takers experience within their culture. Since many
of the objects are taken from Western culture, those not familiar with this culture may
- Persons who find it difficult to detach themselves emotionally from each object also
score poorly. Why?
- Persons who are impulsive also score low (quick responses without detail analysis). Low
scorers may also have poor concentration, and poor visual organization.
- Persons scoring high are alert, have good visual acuity, and have the ability to
recognize important visual information.
2. Picture Arrangement
- A) Ability to plan and anticipate consequences (understanding an entire situation).
- B) Time conception and sequencing.
- C) Understanding nonverbal interpersonal situations.
- D) Speed of planning and associating information.
- Picture arrangement is a test of ability to plan, interpret, and anticipate social
events within a cultural context. Obviously then, experience will play a role.
- Picture arrangement and block design are key measures of nonverbal intelligence, with
block design being less influenced by culture.
- Picture arrangement is very sensitive to brain damage in areas that disrupt nonverbal
social skills (right anterior temporal lobe or frontal lobe impairment).
- 2 methods are generally used to gain information on the test takers. Method 1 observes
and records how the person attempts to solve the problem. Questions like the following
should be asked, Does the test taker carefully consider the overall problem or do
they impulsively start sorting the cards? Is the test taker easily distracted? Is the test
taker easily discouraged or are they persistent?
- Method 2 involves asking the test taker, after the completion of the entire subtest, for
a verbal description of the stories related to the pictures. Questions like the following
are used, Tell me what is happening in the pictures or Make up a story
about the cards.
- Questions you should ask yourself about the test takers stories: Are they logical,
fanciful, or bizarre? Are they original or rather conventional? Do the test takers reveal
any emotional attitudes relating to themselves or their interpersonal relationships? Were
the errors the result of incorrectly perceiving specific details or from not considering
certain key details?
- High scoring persons are usually sophisticated, have high levels of social intelligence,
and can quickly anticipate consequences of initial acts.
- Low scorers tend to have difficulty planning ahead, process information very slowly,
have a poor sense of humor, and tend to have problems with interpersonal relationships.
3. Block Design
- A) Analysis of whole into its parts.
- B) Spatial visualization;
- C) Nonverbal Concept Formation;
- D) Visual-motor coordination and perceptual organization;
- E) Ability to concentrate and perceptual speed.
- Block design is my favorite subtest. Hint! Hint!
- It involves nonverbal problem solving skills since it requires an understanding of a
problems components and then putting these components back into a whole.
- This test is very sturdy and reliable, and correlates highly with general intelligence.
- To score well a person must be able to think abstractly and demonstrate a high degree of
flexibility since the frame of reference changes quickly.
- Administration is such that the researcher can directly observe the test takers
responses. Some will give up quickly and throw the blocks away, others will continue to
work past the time limits. What other types of information are you then getting?
- It is relatively culture free, and has low correlations (.4) with education! What
does this mean?
- Depression and right hemisphere brain damage (particularly parietal lesions)
significantly lower block design scores. Why?
- Persons afflicted with Alzheimers score very low on block design. It is often
their lowest score. It is a good tool for early diagnosis/detection of Alzheimers.
4. Object Assembly
- A) Ability to benefit from sensory-motor feedback.
- B) Visual-motor integration.
- C) Holistic processing (parallel processing).
- D) Synthesis. Putting things together in familiar configurations.
- E) Differentiation of familiar objects.
- Object Assembly is a great test of motor coordination and control (like block design and
- It is a simple test and scores can fluctuate greatly, because the flat cardboard
representations can sometimes accidentally fit together. This tends to inflate test
- Sometimes persons who score poorly on overall intelligence do great on object assembly.
Thus, it does not correlate well with overall intelligence or the other subtests. It is
the poorest subtest in terms of psychometrics. As a result, many researchers do not use
- Despite these problems, object assembly does provide additional information on problem
solving ability in a different type of context. Object assembly is a much more
open problem solving situation.
- Persons who have difficulty changing their frame of references (e.g.,
obsessive-compulsive persons) tend to do very poorly.
- Persons who score well or poorly on block design tend to score similarly with object
5. Digit Symbol/Coding
- A) Psychomotor speed with paper-and-pencil, ability to follow directions, short-term
- B) Ability to learn a new task. Ability to quickly shift mental sets.
- C) Capacity for sustained attention and concentration.
- D) Sequencing ability.
- To score high persons need to have high psychomotor speed as well as good visual-motor
- The test requires appropriately combining newly learned memory of the digit with a
- Digit symbol is highly sensitive to both organic and functional impairments. As with
block design depressed and brain damaged persons have a great deal of difficulty with this
test. Scores are also highly dependent on age. The older you are the poorer your
- Why do you think persons with high reading and writing experience score particularly
- Since much time pressure exists, anxiety, obsessiveness, and perfectionism significantly
lower scores. Why do highly competitive but anxious persons score poorly?
- Persons with learning disabilities score low, as do persons with minimal brain damage.
What does this suggest to you?
- Fast growing brain tumors are affected persons scores more than slow growing brain
6. Symbol Search
- A) Speed of visual search.
- B) Planning and speed of information processing.
- C) Encoding information for further processing (learning).
- It is designed to be a pure test to assess information-processing speed.
- Symbol search is similar to digit symbol, except it correlates better with full scale IQ
(r = 0.58) than digit symbol (r = .35).
- High scores indicate that test takers rapidly absorb information and can also integrate
and respond to this information. Good amounts of visual-motor coordination,
short-term visual memory, planning, attention, and concentration are also needed.
- Low scores suggest slow mental process, visual perceptual troubles, lack of motivation,
anxiety, and short-term memory impairment. A reflective, perfectionistic, or
obsessive problem-solving style also tends to lower scores.
7. Matrix Reasoning
- A) Foresight (planning ability).
- B) Nonverbal reasoning (perceptual organization).
- C) Visual-motor coordination and speed.
- This, like symbol search, is another new test.
- Supposedly, high scores indicate an efficiency for planning ahead, and a flexible mental
orientation. These abilities suggest and excellent ability to inhibit impulsive
- Low scores reflect impulsivity and poor visual-motor coordination. Often low
scores also indicate frontal cerebral impairment.
Reliability and Validity of the WAIS-R (previous version).
- Both the reliabilities and validities for the WAIS-R are quite high.
- Here are a sample of some of the numbers:
- Split-half reliability: Full Scale IQ: 0.95; Verbal IQ: 0.97; Performance IQ: 0.93.
- The subtest are more variable: Vocabulary: 0.96; Object Assembly: 0.52.
- Test-retest reliabilities 1 week: Full: 0.95; Verbal: 0.97; Performance: 0.93.
- Test-retest was lower for the specific tests: Average 0.70.
- What does test-retest reliability tell you? Do the means change?
- Yes, on the second trial Full IQ was 6.2 points higher. Is this meaningful?
- Most researchers suggest not. A meaningful difference is thought to be about 15 points
for the verbal component and 20 points for performance.
- SEM (standard error of measurementconfidence intervals (CI)) for the Full Scale IQ
is 2.53 (What is the 95% CI?); Verbal = 2.74; Performance = 4.14.
- The validity measures that do exist for the WAIS-R have been good, however, many
researchers suggest that more should be validity studies are needed.
- Criterion-related validity with other tests of intelligence: Stanford-Binet 0.85.
- Construct validity: All subtests have moderate to high correlations with general
- Factor analysis structure studies also support the basic verbal and performance domain
- Theoretical predictions suggest that performance IQs scores should decline with age,
while verbal IQs should remain relatively stable. These predictions have been confirmed.
- Similarly, theory predicts that white-collar workers should have higher verbal IQs than
blue-collar workers. And blue-collar higher performance IQs than white-collar. These
predictions have generally been confirmed.
Some Administration Points
- The Wechsler manuals provide clear guidelines for administration and scoring. However,
administration errors are very common. Why?
- Research suggests that even seasoned professionals practice their mistakes rather than
correct them. Some of the common errors include: lack of proper instruction; lack of
proper training; carelessness; variations in the quality of the test taker test
giver relationship. Specifically, the most common errors include:
- A) Failure to record test taker responses, circle scores, or record times.
- B) Too lenient or too tough! Give too many or too few points for an answer.
- C) Failing to question when required by test manual.
- D) Improper questioning of test taker.
- E) Clerical errors (improper conversion of raw to standard scores, calculation of
chronological age, etc.)
- Recite digits at the rate of 1 per second. You voice pitch should drop on the last digit
if each trial.
- Tell test takers that each section begins with easy questions and ends with harder ones.
Also tell them that not everyone is expected to succeed on all questions.
- Get the orientation of the blocks correct and do so at the test takers midline.
- Be sure the test taker is comfortable.
- In order to minimize mistakes optimal training of examinees is essential. Research
suggests a protocol for learning to administer the test.
- 1) 3 4 hours of studying the manual;
- 2) Viewing of videotapes that demonstrate flawless administration;
- 3) Viewing of videotapes that demonstrate flawed administrations. Then have students
- 4) Actually administration of the WAIS (many times and videotaped) and have each or some
administrations critically evaluated.
Steps on How to Interpret a WAIS
- 1) Interpret the full scale IQ.
- That is, determine the test takers percentile rank and thus their IQ
classification (see handout).
- 2) Interpret Verbal-Performance, Factor Scores, and Other Groupings.
- A) Is there a greater than 12 point or greater difference in V-P?
- B) Determine the Factor Scores: I) Verbal comprehension; II) Perceptual Organization;
III) Freedom from distractibility, IV) Working Memory, V) Processing Speed. Now assess to
determine if significant differences exist between these factors and Full-Scale, Verbal or
- C) Determine the Other Grouping Scores (see below, i.e., ACID/SCAD profiles), and
- 3) Interpret Subtest Variability (This is sometimes referred to as Profile Analysis)
- A) Are the subtest fluctuations significant?
- B) If so, develop hypotheses related to the meaning of these subtests.
- C) Integrate these hypotheses into overall assessment.
- 4) Conduct quantitative and qualitative analyses.
- See Handout and insert the cutoffs below on the handout.
- Here are the cut values and their meanings.
- 130 + : Very Superior
- 120-129: Superior
- 110-119: High Average
- 90-109: Average
- 80-89: Low Average
- 70-79: Borderline
- 69 - : Intellectually deficient.
- How do clinicians estimate premorbid IQ of persons with know brain damage?
- Here's a formula with the weighting of each demographic. Try it!
- Estimate of Full Scale IQ = 54.96 + 0.47 (age) + 1.76 (sex) + 4.71 (race) + 5.02
(education) + 1.89 (occupation) + 0.59 (region).
- Where: Age 16 - 17 = 1; 18 - 19 = 2; 20 - 24 = 3; 25 - 34 = 4; 35 - 44 = 5; 45 - 54 =6;
55 - 64 = 7; 65 - 69 = 8; 70 - 74 = 9.
- Sex: Female = 1; Male =2.
- Race: African American = 1 ; Other ethnicity =2; European = 3;
- Education: 0 - 7 years = 1; 8 years = 2; 9 -11 years = 3; 12 years = 4; 13 - 15 years =
5; 16 or more years = 6.
- Occupation: Professional and technical = 6; managers, officials, clerical and sales
workers = 5; craftspersons and skilled workers = 4; not in work force =3; service workers,
farmers, semiskilled = 2; laborers and unskilled workers = 1.
- Region: South US =1; North Central =2, West =3, Northeast = 4
Detection of Alzheimer's Disease
- The initial signs of Alzheimer's disease are the following:
- Decline in short-term memory;
- Difficulties with problem solving;
- To use the WAIS-R to help identify Alzheimer's determine the following scores: A, B, C,
- A = Information + Vocabulary/2;
- B = Similarities + Digit Span/2;
- C = Digit Symbol + Block Design/2
- D = Object assembly.
- The following order occurs in about 40% of Alzheimer's cases. It's not perfect, but it
is a start.
- A > B > C < D and A > D
- Please note that I could not find information with respect to the WAIS-III and
Alzheimer's. I suspect the results should be even better considering that a new index,
'working memory' exists.