142 PSYCHOLOGY
of research on intelligence. His work culminated in a set of highly regarded intel-
ligence tests called collectively the Wechsler Scales.There are three individual
tests, and in revised editions they are still used today. The three tests are: (1) the
Wechsler Preschool and Primary Scale of Intelligence (WPPSI),(2) the
Wechsler Intelligence Scale for Children (WISC),and (3) the Wechsler
Adult Intelligence Scale (WAIS).
The Wechsler Scales have a clear-cut advantage over the Stanford-Binet Scale.
The Stanford-Binet measures general intelligence without regard to specific men-
tal abilities. The Wechsler Scales recognize that there are different kinds of intelli-
gence. Two in particular are emphasized: verbal intelligence and performance
intelligence. Verbal intelligenceincludes such abilities as word fluency, abstract
reasoning, and mathematical ability. Performance intelligenceincludes such
abilities as visualization, the perception of the relationship of parts to a whole, and
the capacity to relate well to other people. As a consequence, it is possible to
obtain two separate IQ scores, a verbal IQ and a performance IQ. The two IQ
scores can be combined for an overall IQ score.(a) What does the abbreviation WAIS stand for?(b) What two kinds of intelligence are clearly identified in the Wechsler Scales?
Answers: (a) Wechsler Adult Intelligence Scale; (b) Verbal intelligence and perform-
ance intelligence.The following description is based on the Wechsler Adult Intelligence Scale.
Not only is the Scale divided into two large areas, it is also subdivided into a set of
eleven subtests, six under the Verbal Scale and five under the Performance Scale.
Keep in mind that the word scaleis used because sets of questions proceed from
easy to difficult. Evaluation is based on how high the subject can climb on the lad-
der of psychological difficulty. Here is the breakdown:The Verbal Scale:Each of the following tests consists of a group of questions
designed to assess a different area.
Information:level of general knowledge.
Comprehension:ability to understand questions and grasp concepts.
Arithmetic:capacity to grasp and employ mathematical concepts.
Similarities:ability to employ abstract thought.
Digit Span:tasks designed to measure attention span.
Vocabulary:grasp of the meaning of words.The Performance Scale:Each of the following tests is a set of tasks designed to
assess a different area.