Wechsler Intelligence Scale for Children
Overview
The Wechsler Intelligence Scale for Children (WISC) is a widely used intelligence test for children between the ages of 6 and 16. Developed by psychologist David Wechsler, the WISC is now in its fifth edition (WISC-V), which was published in 2014. The test is designed to measure a child's intellectual abilities in a variety of areas, including verbal comprehension, visual-spatial processing, fluid reasoning, working memory, and processing speed.
History
The WISC was first published in 1949 as a revision of the Wechsler-Bellevue Intelligence Scale, a test for adults. The original WISC was designed for children aged 5 to 15 and included subtests that measured both verbal and performance abilities. Over the years, the WISC has been revised and updated several times, with the most recent edition, the WISC-V, being published in 2014.
Structure
The WISC-V is composed of 15 subtests, 10 of which are core subtests used to derive the Full Scale IQ (FSIQ) score. The five remaining subtests are supplemental and can be used to provide additional diagnostic information. The core subtests are divided into five primary index scales: Verbal Comprehension Index (VCI), Visual Spatial Index (VSI), Fluid Reasoning Index (FRI), Working Memory Index (WMI), and Processing Speed Index (PSI).
Verbal Comprehension Index
The VCI measures a child's ability to listen to a question, draw upon learned information from both formal and informal education, reason through an answer, and express thoughts aloud. It includes three core subtests: Similarities, Vocabulary, and Information.
Visual Spatial Index
The VSI assesses a child's ability to evaluate visual details and understand visual spatial relationships to construct geometric designs. It includes two core subtests: Block Design and Visual Puzzles.
Fluid Reasoning Index
The FRI measures a child's ability to detect the underlying conceptual relationship among visual objects and use reasoning to identify and apply rules. It includes two core subtests: Matrix Reasoning and Figure Weights.
Working Memory Index
The WMI assesses a child's ability to register, maintain, and manipulate visual and auditory information in conscious awareness. It includes two core subtests: Digit Span and Picture Span.
Processing Speed Index
The PSI measures a child's speed and accuracy of visual identification, decision making and decision implementation. It includes two core subtests: Coding and Symbol Search.
Scoring
Each of the subtests in the WISC-V is scored based on the child's age, with higher scores indicating better performance. The scores from the subtests are combined to create the five primary index scores, which are then combined to create the Full Scale IQ score. The FSIQ is a composite score that summarizes the child's overall intellectual abilities.
Applications
The WISC-V is used for a variety of purposes, including the assessment of intellectual abilities in children, the identification of learning disabilities and attention deficit hyperactivity disorder (ADHD), and the evaluation of the effectiveness of interventions. It is also used in research to study the relationship between intelligence and other psychological and behavioral variables.
Limitations
While the WISC-V is a comprehensive and widely used measure of intelligence, it has some limitations. For example, it may not fully capture the intellectual abilities of children with nonverbal learning disabilities or those from culturally and linguistically diverse backgrounds. Furthermore, the test is time-consuming to administer and requires a high level of training to interpret the results accurately.