The Wechsler Adult Intelligence Scale

The Wechsler Adult Intelligence Scale (WAIS) is an intelligence test first published in 1955 and designed to measure intelligence in adults and older adolescents. The test was designed by psychologist David Wechsler, who believed that intelligence was made up of a number of different mental abilities rather than a single general intelligence factor.

This article discusses the history of the Wechsler Adult Intelligence Scale, the different versions of the test, and how the test is used. It also explores the benefits and limitations of the WAIS.

History of the Wechsler Adult Intelligence Scale

Wechsler was dissatisfied with what he believed were the limitations of the Stanford-Binet intelligence test. Among his chief complaints about that test was the single score that emerged, its emphasis on timed tasks, and the fact that the test had been designed specifically for children and was therefore invalid for adults.

As a result, Wechsler devised a new test during the 1930s, known as the Wechsler-Bellevue Intelligence Scales. The test was later revised and became known as the Wechsler Adult Intelligence Scale, or WAIS.

WAIS vs. Stanford Binet

One interesting thing to note is that Alfred Binet, the developer of the world's first intelligence test, also believed that intelligence was far too complex a subject to be sufficiently described by a single number.

The goal of his original test was to help identify children who needed specialized help in school. Binet felt that a variety of individual factors, including a child's level of motivation, could influence test scores.

In a sense, Wechsler's test was a return to many of the ideas that Binet had also espoused. Instead of giving a single overall score, the WAIS provides a profile of the test-taker's overall strengths and weaknesses.

One benefit of this approach is that the pattern of scores can also provide useful information. For example, scoring high in certain areas but low in others might indicate the presence of a specific learning disability.

How the WAIS Is Scored

Like the traditional Stanford-Binet test, the WAIS also provides an overall score. However, Wechsler utilized a different approach to calculating this number. As you might remember from reading about the history of intelligence testing, scores on the early Stanford-Binet were derived from dividing mental age by chronological age.

On the WAIS, Wechsler instead compared the scores of the test-taker to those of others in their general age group. The average score is fixed at 100, with approximately two-thirds of all scores falling somewhere between 85 and 115.

Versions of the WAIS

There have been four different versions of the WAIS over the years. 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

The current version of the WAIS was released in 2008 and includes ten core subtests as well as five supplemental subtests. Additionally, the WAIS-IV test provides four major scores.

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.

Today, the WAIS is the most frequently used intelligence test in the world for both adolescents and adults. Data collection for the newest version of the test (WAIS-V) is progressing through spring 2020.

Benefits of the Wechsler Adult Intelligence Scale

The Wechsler Adult Intelligence Scale is widely used for a number of reasons. Some benefits include the following:

• The test is well-established and has good test-retest reliability. 
• It accurately measures a person's current intellectual status and functioning.
• Research suggests that the WAIS-IV can be a useful clinical tool for assessing mild, moderate, and severe traumatic brain injury (TBI).

Limitations of the Weschler Adult Intelligence Scale

While the WAIS can be a useful clinical tool, it does have some limitations and drawbacks. Some of these include:

• The test does not assess non-academic skills that can play an important role in success and well-being, such as motivation, creativity, emotional intelligence, and social skills.
• The test can provide a relative measure, but it does not offer a fully view of a person's abilities, talents, or potential. 
• The tests cannot be utilized with individuals with vision, auditory, or motor impairments.
• Versions of the test for non-English speakers are limited. There are currently two Spanish versions (one for Spanish speakers from Spain and one for Spanish speakers from Mexico).
• Scores on subtests may also differ for neurodivergent adults. People may score higher or lower on certain subtests depending on their unique traits and characteristics.
• May not be suitable for older adults, especially those over the age of 89.

Current Uses

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
• Assess functioning in people with brain injury
• Evaluating patterns of brain dysfunction
• Diagnostic purposes
  

A Word From Verywell

The Weschler Adult Intelligence Scale can be a useful 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.