WAIS: WECHSLER ADULT INTELLIGENCE SCALE
The Wechsler Adult Intelligence Scale (WAIS) is an intelligence test developed by Dr. David Wechsler, an American psychologist, in 1955 to measure cognitive ability and intelligence in adults and older adolescents.
VERSIONS OF THE WAIS
There have been four versions of the Wechsler Adult Intelligence Scale (WAIS) tests:
- WAIS (1955): The original Wechsler Adult Intelligence Scale, developed by David Wechsler. This test was an adaptation and expansion of the earlier Wechsler-Bellevue Intelligence Scale, developed in 1939.
- WAIS-R (1981): The first revision of the test, which included updates on test items and norms to improve the test’s reliability and validity. Also provided a verbal IQ score, performance IQ score, and overall IQ score.
- WAIS-III (1997): The WAIS-III introduced further refinements, and new subtests, and included secondary scores for verbal comprehension, working memory, perceptual organization, and processing speed.
- WAIS-IV (2008): The WAIS-IV is the most recent version made up of 10 main subtests organized into four index scores: Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed.
WAIS-IV
The current version of the WAIS was released in 2008 and is currently the most used intelligence test worldwide. The test includes the four index scores:
- Verbal Comprehension Index (VCI): Focuses on vocabulary, verbal reasoning and language skills acquired from one’s environment.
Core Subtests:
- Similarities
Task: The individual must describe how two words or concepts are alike (e.g., “In what way are a lion and a tiger alike?”)
Skills Assessed: Abstract thinking, verbal concept formation, and categorization.
- Vocabulary
Task: The individual provides definitions for a series of words.
Skills Assessed: Vocabulary knowledge, verbal expression, and language development.
- Information
Task: The individual answers questions covering a range of general knowledge topics.
Skills Assessed: General knowledge, long-term memory, and verbal comprehension.
2. Perceptual Reasoning Index (PRI): Evaluates non-verbal and fluid reasoning, spatial processing, and an individual’s ability to analyze and solve visual-spatial problems.
Core Subtests:
- Block Design
Task: The individual replicates designs using coloured blocks within a time limit.
Skills Assessed: Visual-motor coordination, spatial processing, and problem-solving.
- Matrix Reasoning
Task: Nonverbal reasoning task in which individuals are asked to identify patterns in designs.
Skills Assessed: Fluid intelligence, pattern recognition, and inductive reasoning.
- Visual Puzzles
Task: The individual selects pieces that can be combined to form a given puzzle.
Skills Assessed: Spatial reasoning, visual processing, and mental rotation.
3. Working Memory Index (WMI): Measures working memory abilities, which involve attention, concentration, mental control, and reasoning. It also measures the mental manipulation of number operations.
Core Subtests:
- Digit Span
Task: The individual repeats sequences of numbers forwards, backwards, and in ascending order.
Skills Assessed: Auditory attention, working memory, and sequencing.
- Arithmetic
Task: The individual solves arithmetic problems presented orally without using paper and pencil.
Skills Assessed: Numerical reasoning, mental calculation, and working memory.
4. Processing Speed Index (PSI): Assesses the speed and accuracy of visual processing. It also measures short-term memory, attention, and visual-motor coordination.
Core Subtests:
- Symbol Search
Task: The individual scans groups of symbols and identifies whether a target symbol is present.
Skills Assessed: Visual discrimination, speed of mental processing, and visual scanning.
- Coding
Task: Individuals are asked to record associations between different symbols and numbers within time limits.
Skills Assessed: Visual-motor integration, processing speed, and fine motor control.
These four index scores provide a broad and detailed profile of an individual’s cognitive strengths and weaknesses, facilitating a deeper understanding of their intellectual abilities and helping guide educational, clinical, and vocational intervention
SCORING
The WAIS-IV provides two overall summary scores including a Full-Scale IQ and a General Ability Index. Scores on the subtests are combined to generate an FSIQ score, which represents an individual’s overall cognitive ability.
APPLICATION
The WAIS is used in a variety of settings, including clinical, educational, and occupational contexts.
- It helps diagnose learning disabilities, cognitive impairments, and mental disorders.
- It is also used in neuropsychological assessments to understand cognitive strengths and weaknesses.
The WAIS is a comprehensive and robust tool for assessing adult intelligence, with a significant impact on the field of psychology.
