Wechsler Adult Intelligence Scale (WAIS)

Ø Author:

David Wechsler, a clinical Psychologist (1896-1981) created what we now refer to as the Wechsler IQ test. He developed the first Wechsler Bellevue Scale in 1939 and 15 years later revised it into the WAIS.

As an aside, David Wechsler’s study of memory loss before the First World War provided a foundation for his curiosity about intelligence and how it is tested. Wechsler eventually became interested in children’s IQ scores. He considered the effect of environment on intelligence and decided that a person’s IQ is open to influences. As well, Wechsler observed that qualities such as persistence can affect general intelligence. He designed intelligence tests that could be applied to a range of ages.

The types of Wechsler intelligence tests include the Wechsler Pre-School and Primary Scale of Intelligence (WPPSI) for ages three to seven years; the Wechsler Intelligence Scale for Children (WISC) for ages seven to 16; and the Wechsler Adult Intelligence Scale (WAIS) for ages 16 and above. (The Wechsler IQ Test)

Ø Operational Definition:

Intelligence:

According to Wechsler “Intelligence is the aggregate or global capacity of the individual to act purposefully, to think rationally and to deal effectively with his environment. (aSGuest104610, Wechsler, 2011)

Ø Reason of Selection:

The Wechsler IQ test and the scale have been adapted in various countries and there have been attempts to make the scale more culturally fair. The Wechsler IQ test has been used for more than 50 years. In fact, the Wechsler Adult Intelligence Scale (WAIS) is among the most widely used scale for IQ tests.

Ø  WAIS-II:

The WAIS-III is the 1997 revision of the test originally published in 1955 and first revised in 1981. (Wechsler Adult Intelligence Scale) It provided scores for Verbal IQ, Performance IQ and Full Scale IQ, along with four secondary indexes (Verbal Comprehension, Working Memory, Perceptual Organization, and Processing Speed). The WAIS-III consists of 14 subtests and takes about 60–75 minutes to complete. The test is taken individually, with a test administrator present to give instructions. Each subtest is given separately, and proceeds from very easy items to very difficult ones. Tasks on the WAIS-III include questions of general knowledge, traditional arithmetic problems, test of vocabulary, and completion of pictures with missing elements, arrangements of blocks and pictures, and assembly of objects.

Ø  Verbal Scales The Verbal Comprehension Index (VCI) included the following tests:

Information: 28 items on a variety of information adults have presumably had opportunities to acquire in our culture. No specialized or academic information included; however, some of the items cover quite sophisticated information.

Comprehension: 18 items that require examinee to explain what should be done in certain circumstances, the meaning of proverbs, why certain societal practices are followed, and so forth. The test measures practical judgment, common sense, and the ability to understand and adapt to social customs. Score on each item varies (0-2 pts) according to the degree to which the response describes the most pertinent aspects of the question.

Vocabulary: 66 words of increasing difficulty are presented orally and visually. Examinee required defining the words. Score (0-2) based on sophistication of definition. It measures verbal knowledge and concept formation.

Similarities: 19 items requiring examinee to describe how two given things are alike. Score on each item varies according to the degree to which the response describes a general property primarily pertinent to both items in the pair. Measures concrete, functional, and abstract concept formation. The Working Memory Index (WMI) included:

Arithmetic: 20 arithmetic problems similar to those encountered in elementary math courses. Problems are administered orally and must be solved without paper and pencil. In addition to math knowledge, test measures concentration and systematic problem-solving ability.

Digit Span: Two parts, Digits forward and digits backwards. Examinee required repeating 3 - 9 digits forward and 2 - 9 digits backwards. Measures short-term memory, attention, and concentration..

Letter-Number Sequencing (Optional Test): Examiner presents combinations of letters and numbers, from 2 to nine letter-number combinations. Examinee must repeat each series by, first, repeating the numbers in ascending order, then the letters in alphabetical order (e.g., 9-L-2-A; correct response is 2-9-A-L). Measures "working memory," the ability to simultaneously recall and organize stimuli of different, similar types. This also is a standard test on the Wechsler Memory Scale-III.

Performance Scales: The Perceptual Organization Index (POI) included:

Picture Completion: 25 cards, each containing a picture having a part missing. Examinee must identify the missing part. It measures the ability to observe details and recognize specific features of the environment (I.e., whole to part discrimination). Also measures performance in deliberately focusing attention.

Block Design:  Perhaps the butt of more jokes than any other WAIS scale! Included in the test are nine red and white square blocks and a spiral booklet of cards showing different color designs that can be made with the blocks. The examinee must arrange the blocks to match the design formed by examiner or shown on cards. In addition to being scored for accuracy, each item is scored for speed as well. It measures spatial problem-solving and manipulative abilities, and part to whole organization.

Matrix Reasoning: A new test on the WAIS-III. Examinee is presented with a series of design with a part missing. Examinee chooses the missing part that will complete the design, from five choices. It measures nonverbal analytical reasoning.

The Processing Speed Index (PSI) included:

Coding-Digit Symbol: Numbers 1 - 7 are paired with symbols on a key presented to examine. Examinee has 120 seconds to go through a grid of 90 numbers and place the correct symbol above each number. It measures visual-motor speed and complexity, motor coordination. There are two additional, optional extensions of the coding test that measure the examinees skills in learning the coding process after completing the initial task.

Picture Arrangement: Eleven items. Each item consists of 3 to 6 cards containing pictures. The examinee must arrange the pictures from left to right to tell the intended story. Again, both accuracy and speed are scored. Partial credit is given for alternate, but less commonly given arrangements to some items. Measures nonverbal reasoning and sequencing skills, and grasp of social cause and effect (also known as social intelligence).

Object Assembly (Optional Test):  Four items, each item being a "cut up" object, like a puzzle. Examinee must correctly assemble the parts of the puzzle. It measures visual-motor problem-solving and organizational abilities, and visual anticipation skills.

Symbol Search (Optional test):  Examinee must match one or two symbols shown on the left column with the same symbol/s in the right column of each page in the supplemental test booklet. Measures organization accuracy and processing speed

The WAIS-III elicits three intelligence quotient scores, based on an average of 100, as well as subtest and index scores. WAIS-III subtests measure specific verbal abilities and specific performance abilities.

The WAIS-III elicits an overall intelligence quotient, called the full-scale IQ, as well as a verbal IQ and a performance IQ. The three IQ scores are standardized in such a way that the scores have a mean of 100 and a standard deviation of 15.

Ø Psychometric Detail:

The WAIS-III is considered to be a valid and reliable measure of general intelligence. When undergoing reliability and validity studies, other intelligence tests are often compared to the Wechsler scales. It is regularly used by researchers in many areas of psychology as a measure of intelligence.

Ø  Validity:

WAISIII correlates highly (mid 90’s) with earlier versions of the WAIS. Correlation with SBIV is .88 Correlates significantly with grades in high school, university IQ and occupational attainment are also significantly correlated. Predictions deriving from theory are borne out; fluid intelligence supposedly declines more rapidly in old age than crystallized intelligence Supported by finding that verbal subtests show minimal decrement with age, while performance subtests drop markedly. (razaqhamdani8625)

Ø Standardization:

A large standardization sample was used of 1880 Americans. This sample was 50% male and 50% female (Wechsler Adult Intelligence Scale (WAIS), 2004). The individuals who formed the standardization sample were aged from 16 years 0 months to 74 years 11 months.  The standardization sample was highly representative of the US population in terms of age, sex, race, geographic region, occupation, education and urban-rural residence. The individuals in the standardization sample were tested between May 1975 and May 1980 at 115 testing centers across the U.S.

The scaled scores were based on a reference group of 500 subjects in the standardization sample aged between 20 and 34. Although scaled scores for each of the 11 subtests are obtained using a single table based on the reference group, IQs are derived separately for each of the age groups (there are nine e.g. 16-17, 18-19, 20-24, 25-34, 70-74). The test can be used for people aged 16 and up. It has found to be appropriate for use with those over 74. So the WAIS has a good standardization sample and it is also considered to be reliable and valid.

The reliability coefficients: (internal consistency) are .93 for the Performance IQ averaged across all age groups and .97 for the Verbal IQ, with an r of .97 for the full scale. Reliability for the 11 subsets is not as strong.

Split half reliability: .95+ (very strong)

Evidence supports the validity of test as a measure of global intelligence.  It does seem to measure what it intends to measure. It is correlated highly with other IQ tests (e.g. The Stanford-Binet), it correlates highly with empirical judgments of intelligence; it is significantly correlated with a number of criteria of academic and life success, including college grades, measures of work performance and occupational level.  There are also significant correlations with measures of institutional progress among the mentally retarded.

Ø  Subsequent Revisions:

• WAIS (1955)
• WAIS-R (1981)
• WAIS-III (1997)
• WAIS-IV (2008)

Ø  Current Version:

It is currently in its fourth edition (WAIS-IV). The original WAIS (Form I) was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale that had been released in 1939. The fourth edition of the test (WAIS-IV) was released in 2008 by Pearson. (Wechsler Adult Intelligence Scale)

Ø  Application:

A short, four-subtest version of the WAIS-III battery has been released, allowing clinicians to form a validated estimate of verbal, performance and full scale IQ in a shorter amount of time. Rehabilitation psychologists and neuropsychologists use the WAIS-IV and other neuropsychological tests to assess how the brain is functioning after injury. Specific subtests provide information on a specific cognitive function. For example, digit span may be used to get a sense of intentional difficulties. Today, various high-IQ societies accept this test for membership in their ranks. For example, the Triple Nine Society accepts a minimum score of 146 on any WAIS scale. (Wechsler Adult Intelligence Scale)

The WAIS has also been found to be a good measure of both fluid and crystallized intelligence. Fluid intelligence refers to inductive and deductive reasoning, skills considered to be largely influenced by neurological and biological factors. In the WAIS, fluid intelligence is reflected in the performance subtests. Crystallized intelligence refers to knowledge and skills that are primarily influenced by environmental and sociocultural factors. In the WAIS, crystallized intelligence is reflected in the verbal subtests. Wechsler himself did not divide overall intelligence into these two types. However, the consideration of fluid and crystallized intelligence as two major categories of cognitive ability has been a focus for many intelligence theorists. (Wechsler adult intelligence scale)

Ø  Purpose:

The purpose of WAIS-III is to provide a measure of general intellectual function in older adolescents and adults. (Esther Strauss, 2006) 

Ø Prevalence in Pakistan

The link mentioned below is website where you can administer the test online. It includes 60 questions and is scored automatically after 40 minutes.

http://wechsleradultintelligencescale.com/

Pakistan Institute of Learning and Living (PILL) is a research based organization. This institution provides training in 5 board areas. One of them is Assessment. In this board of area they provide training in IQ Assessment and Wechsler Intelligence Scale of Adults (WAIS). (Pakistan Intitute of Learning and Living: Training and Development)

Ø  Examples: Examples of this type of question are as follows.

Similarities sub-test question:

·         How are a cat and a mouse alike?

·         Possible Answers:

·         The cat chases the mouse – 0 points

·         They are both pets or they both have fur or are brown – 1 point

·         They are both animals – 2 points

·         Vocabulary sub-test question:

·         What does ancient mean?

·         Possible Answers:

·         Something over 50 years old – 0 points

·         Something very old – 1 point

·         Something from a very long time ago; hundreds of years old – 2 points