The Wechsler Adult Intelligence Scale (WAIS) is a globally recognized test designed to measure cognitive abilities in adults and older adolescents. It’s named after its originator, David Wechsler, a psychologist who believed that intelligence isn’t a singular, general factor, rather it’s composed of several distinct mental abilities. As such, the WAIS is structured to assess various aspects of intelligence, offering a comprehensive view of an individual’s cognitive functioning.
The Historical Perspective of the Wechsler Adult Intelligence Scale
David Wechsler, dissatisfied with the limitations of the Stanford-Binet intelligence test, devised a new test in the 1930s known as the Wechsler-Bellevue Intelligence Scales. His main criticisms of the Stanford-Binet test were its emphasis on timed tasks, the emergence of a single score, and the fact that the test was specifically designed for children, making it invalid for adults. As a result, Wechsler’s test was a return to many of the ideas that Alfred Binet, the developer of the world’s first intelligence test, also espoused.
The Wechsler-Bellevue test was later revised and became known as the Wechsler Adult Intelligence Scale (WAIS), introduced in 1955. Over the years, the WAIS has undergone numerous revisions, with the current version being the WAIS-IV, also known as the fourth edition.
WAIS Compared to Other Intelligence Tests
In contrast to the Stanford-Binet test, the WAIS provides a profile of the test-taker’s overall strengths and weaknesses rather than a single overall score. This approach offers a more comprehensive view of an individual’s cognitive abilities. Scoring high in certain areas but low in others might indicate the presence of a specific learning disability.
The WAIS also utilizes a different approach to calculating the overall score. While the Stanford-Binet test derived scores from dividing mental age by chronological age, the WAIS compares the scores of the test-taker to those of others in their general age group.
Structure of the Wechsler Adult Intelligence Scale
The WAIS-IV, the latest version of the WAIS, consists of 10 core subtests and five supplemental tests. These tests are used to obtain an overall score and are divided into four major indexes: Verbal Comprehension (VCI), Perceptual Reasoning (PRI), Working Memory (WMI), and Processing Speed (PSI).
Each of these indexes assesses a different aspect of intelligence:
- Verbal Comprehension Index (VCI): This index measures the application of verbal skills and information to problem-solving.
- Perceptual Reasoning Index (PRI): This index measures the ability to engage in nonverbal reasoning using visual images.
- Working Memory Index (WMI): This index measures working memory, short-term memory, sustained attention, and auditory processing.
- Processing Speed Index (PSI): This index measures visual-motor coordination, attention, concentration, and the speed of mental processing.
Scoring in the WAIS
The WAIS-IV provides a Full Scale IQ score that is the aggregate of the four index scores. The average score is set at 100, with approximately two-thirds of all scores falling somewhere between 85 and 115. Test scores that fall between 90 and 110 are considered average intelligence.
Different Versions of the WAIS
Over the years, there have been four different versions of the WAIS. These include:
- WAIS (1955): The original test was a revision of the Wechsler-Bellvue Intelligence Scale, a test that was first released in 1939.
- WAIS-R (1981): The first revision of the test added new norms but relied on validity data from the original test. It also included six verbal and five information subtests and provided a verbal IQ score, performance IQ score, and overall IQ score.
- WAIS-III (1997): This test version included seven verbal and six performance subtests. Along with providing scores for verbal, performance, and overall IQ, the test also includes secondary scores for verbal comprehension, working memory, perceptual organization, and processing speed.
- WAIS-IV (2008): This version of the WAIS is made up of 10 main subtests and five supplemental tests. The 10 core subtests are then used to obtain an overall score.
Current Version of the WAIS
The current version of the WAIS, the WAIS-IV, was released in 2008. It includes ten core subtests and five supplemental subtests. The WAIS-IV test provides four major scores:
- Perceptual Reasoning
- Processing Speed
- Verbal Comprehension
- Working Memory
The WAIS-IV also provides two overall summary scores including a Full-Scale IQ and a General Ability Index. The WAIS surpassed the Stanford-Binet in use during the 1960s and is currently the most frequently used intelligence test in the world for both adolescents and adults.
Benefits and Limitations of the Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale has numerous benefits, including its well-established nature and good test-retest reliability. It accurately measures a person’s current intellectual status and functioning and can be a useful clinical tool for assessing traumatic brain injury.
However, the WAIS does have some limitations. The test does not assess non-academic skills that play an important role in success and well-being, such as motivation, creativity, emotional intelligence, and social skills. It also cannot be utilized with individuals with vision, auditory, or motor impairments. Versions of the test for non-English speakers are also limited.
Current Uses of the WAIS
Today, the Wechsler Adult Intelligence Scale continues to be one of the most widely used clinical instruments. In addition to being used to measure adult and adolescent intelligence, clinicians use the test to assess cognitive functioning in people with psychiatric conditions, people with brain injury, evaluate patterns of brain dysfunction, and for diagnostic purposes.
Conclusion: The Importance of the Wechsler Adult Intelligence Scale
The Weschler Adult Intelligence Scale is a valuable tool for clinicians to assess cognitive functioning. It may be used to assess intelligence, but it is frequently utilized to look at cognitive abilities in people who have experienced brain trauma or psychiatric illness. If you are interested in taking the WAIS, it is crucial for it to be given by a trained and experienced administrator who is familiar with the testing and scoring protocols.
