Wechsler-Bellevue Intelligence Scale
Introduction
The Wechsler-Bellevue Intelligence Scale, developed by psychologist Dr. David Wechsler, is a cognitive ability assessment tool that measures intelligence across different cognitive domains. It was first published in 1939 and has undergone several revisions since its inception, with the most recent version being the Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV).
Historical Background
The Wechsler-Bellevue Intelligence Scale was the first of its kind to assess both verbal and performance intelligence, a departure from the then-dominant Stanford-Binet scale which focused primarily on verbal intelligence. Wechsler's approach was based on his belief that intelligence was a broad, multi-faceted construct that could not be adequately measured through verbal tasks alone.
Structure
The Wechsler-Bellevue Intelligence Scale is divided into two main sections: the Verbal Scale and the Performance Scale. Each of these scales is further divided into several subtests, each designed to measure a specific aspect of cognitive functioning.
Verbal Scale
The Verbal Scale consists of six subtests: Information, Comprehension, Arithmetic, Similarities, Digit Span, and Vocabulary. These subtests measure various aspects of verbal intelligence, including general knowledge, verbal reasoning, numerical reasoning, short-term memory, and language proficiency.
Performance Scale
The Performance Scale, on the other hand, consists of five subtests: Picture Completion, Picture Arrangement, Block Design, Object Assembly, and Digit Symbol. These subtests measure non-verbal intelligence, including spatial reasoning, perceptual organization, and processing speed.
Scoring
The Wechsler-Bellevue Intelligence Scale uses a three-tiered scoring system: raw scores, scaled scores, and an overall intelligence quotient (IQ). Raw scores are the number of correct responses given by the examinee, which are then converted into scaled scores based on the examinee's age. The scaled scores from the Verbal and Performance Scales are then combined to calculate the examinee's Full Scale IQ.
Applications
The Wechsler-Bellevue Intelligence Scale is widely used in various settings, including clinical, educational, and research contexts. It is often used to identify intellectual disabilities, learning difficulties, and cognitive impairments, as well as to assess cognitive functioning in individuals with neurological conditions or psychiatric disorders.
Criticisms and Controversies
Despite its widespread use, the Wechsler-Bellevue Intelligence Scale has been subject to several criticisms. Some critics argue that the test is culturally biased, as it was developed based on Western norms and standards. Others contend that the test does not adequately measure all aspects of intelligence, particularly those related to creativity and emotional intelligence.