WAIS-IV intelligence test (Wechsler Scale in Adults)

The different versions of the Wechsler Intelligence Scale for Adults have dominated the field of cognitive assessment in people over 16 years of age since the 1950s and have made a decisive contribution to the conception of intelligence in the field of psychology and in society in general.

In this article we will analyze the main scales and tests of the WAIS intelligence test. We will focus in particular on the latest version, the WAIS-IV scale, although we will begin by reviewing the history of this method of assessing cognitive abilities.

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The Wechsler Adult Intelligence Scale (WAIS)

David Wechsler (1896-1981) was an American psychologist who was trained with Karl Pearson and Charles Spearman, pioneers of psychometry. In 1955 he published the first version of the test that we know as "Wechsler Adult Intelligence Scale", commonly called "WAIS" for its initials in the original English.

Previously, in 1939, this author had contributed to the creation of the Intelligence Scale Wechsler-Bellevue, which can be considered a direct precursor of what would be the definitive work of Wechsler. Both tests

they conceived intelligence as a set of interrelated elements that could be measured independently.

In 1981 a revised version of the Wechsler Adult Intelligence Scale (WAIS-R) appeared. Later, in 1997, the WAIS-III was launched; This new test contained updated scales applicable to many types of population and distinguished between the verbal and manipulative intelligence quotient, in addition to the total, which was obtained by combining the two previous.

The most recent version of the Wechsler test is the WAIS-IV, which was published in 2008. In this, the verbal and manipulative quotients are replaced by four more specific indices (verbal comprehension, reasoning perceptual, working memory and processing speed) and a General Ability Index is added that is used in the field clinical.

Since the first WAIS, these tests have focused on evaluating people over the age of 16. There are also the Wechsler Intelligence Scale for Children (WISC) and the Wechsler Scale of Intelligence for Preschool and Elementary (WPPSI). Currently the WISC is in its fifth version and the WPPSI in the fourth, and the fifth WAIS is being worked on.

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Scales and main tests of the WAIS-IV test

Wechsler intelligence tests measure different abilities using specific tests. Some of the most characteristic are Symbol Search, which consists of identifying visual elements the most quickly possible, Matrices, similar to intelligence tests like Raven's, or Information, which assesses knowledge general.

Each of these tests weights in a larger index. In the WAIS-III the Verbal Comprehension and Working Memory indices were part of the Verbal IQ, while Perceptual Organization and Processing Speed ​​were part of the manipulative IQ; Nevertheless, in the WAIS-IV we only find these indices together with the total IQ, which combines them.

1. Verbal comprehension

The Verbal Comprehension index reflects the ability of a given individual to understand and use verbal language, in addition to the reasoning skills associated with this type of material. It is also a good indicator of the quantity and quality of the knowledge acquired, and also the recovery of long-term memories.

The main tests of the Verbal Comprehension index are the Similarities, the Vocabulary and the Information tests. On the other hand, the Comprehension test can be used as a complementary factor in the calculation of this index.

2. Perceptual reasoning

The terminology "Perceptual Reasoning" replaced that of "Perceptual Organization" in the passage from the third WAIS to the fourth. This factor measures the ability of the person evaluated to interpret, organize and think correctly using visual information; therefore, it is related to fluid reasoning and perception rather than verbal.

The classic tests that make up this index are Design with cubes (create figures seen in images using cubes), Matrices and Incomplete figures. It also includes two new tests: Visual Puzzles and Figurative Weight. The first is central to the calculation of the Perceptual Reasoning index, while Figurative Weight is a complementary subtest.

3. Work memory

The Working Memory index assesses the ability to grasp and retain information in the short term, as well as to carry out cognitive operations on it. It is made up of two basic tests: Arithmetic and Digit Hold. It also includes the supplementary test Succession of Numbers and Letters.

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4. Processing speed

Processing speed is a measure of individual abilities to process visual information quickly and efficiently. The test results that make up this index also serve as a secondary indicator of motor speed.

The two main tests that weights in this index are Symbol Search and Keys. Cancellation, which is the only new test on the WAIS-IV along with Visual Puzzles and Figure Weight, serves as a supplemental factor.

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