The Wechsler Intelligence Scales

Dr. David Wechsler was an employee of Bellevue Hospital as a psychologist. He established the Wechsler intelligence degrees and the outcomes of his research were printed in the year 1939. Wechsler built the Wechsler-Bellevue Intelligence scale on the basis of his observation that, tests for adults at the time were mere adaptations of tests used on children (Andrew, 2010). This he noticed had little validity for older people. From 1939, there has been the creation of three scales, which have been consequently revised. These scales have and are still used to gauge the rational functioning of grown-ups and children.

The scales include Wechsler Adult Intelligence Scale-III or WAIS-III. This scale is used to test the intelligence of the adult population. The second is the Wechsler Intelligence Scale for Children-III or the WISC-III which is intended for children in the age bracket 6-16. Lastly, there is the Wechsler preschool and primary scale of Intelligence-R or the WPPSI-R which is intended for children from the age of 4-61/2 (Eldon, 2008). This study will be validating the nature of the WISC-III Functional Distractibility factor.

According to Wechsler, intelligence is the individual’s ability to acclimatize and fruitfully solve problems in the surroundings. He understood intelligence based on performance rather on ability (Gary, 2009). The basis for taking intelligence as a variable of performance is that it does not matter how vast an individual’s intelligence is for him to adapt to the surroundings. The manner in which a person uses this intelligence is considered important. Since rational ability is conceptual and cannot be seen, its’ measurement is not consistent. Performance is quantifiable and thus should be the test’s point of concentration (Lawrence, 2006).

Children’s intellectual functioning has been widely been based on the WISC-III. Research on WISC-III have brought a general agreement that the instrument gauges verbal understanding and perceptual association abilities (Michel, 2003). However, there is disagreement on the existence of the other two abilities, which can be tapped by the WISC-III instrument. In the WISC-III handbook these constructs were referred to as Freedom from Distractibility or FD and the Processing Speed. This is predominantly the case concerning the FD factor, which has led to extensive debate on the handbook regarding what can or cannot be measured (Michel, 2004).

As a result, the thesis will be on examining the nature of the WISC-III FD factor. This will be done by administering the WISC-III together with memory span and quantitative reasoning marker tests. This will be administered to a sample of 100 students who will be referred to determine their special education services eligibility. The resulting factors shall be subjected to confirmatory factor analysis. Results will be used to gauge the effect of administering the WISC-III together with marker tests for memory extent and quantitative reasoning. Scrutiny of the solution will be used to suggest the most appropriate factors.

These factors are Perceptual Organization, Verbal Comprehension, Quantitative Reasoning, Processing Speed, and the Memory Span (Robert & Dennis, 2009). The analysis of the subtests will compromise the WISC-III ED factor, Digit and Arithmetic Span laden on separate factors. Quantitative Reasoning factor will be tested by the use of Arithmetic subtests together with quantitative reasoning marker tests. On the other hand, the Memory Span factor will be tested by the use of Digit Span subtest together with memory span marker tests. The findings of this study will be used to show the use of WISC-III FD.


Andrew, D. (2010). The Handbook of Pediatric Neuropsychology. New York: Springer.

Eldon, C. (2008). Visual-spatial processing and mathematics achievement. Hoboken. Wiley.

Gary, G. (2009). Handbook of psychological assessment. Hoboken: John Wiley & Sons.

Lawrence, G. (2006). Practical resources for the mental health. Burlington: Academic Press.

Michel, H. (2003). Comprehensive Handbook of Psychological Assessment. New York: Wiley.

Michel. H. (2004). Comprehensive Handbook of Psychological Assessment. Hoboken: Wiley.

Robert, M., & Dennis, P. (2009). Psychological Testing: Principles, Applications, and Issues. Belmont: Wadsworth Cengage Learning.