The tests are used for children from 3-14, without differentiation for adolescents and adults. The revisions of Binet scale are: Goddard (1911); Goddard and Kuhlmann (1911); Lewis M.
Terman (1912, 1915); Maude E Merrill (1937) and finally Terman and Maude (1960).
2. The Wechsler-Bellevue Intelligence Test:
This is a test battery of ten subtests for general intelligence. The selection of subtests and their grouping in a verbal scale and a performance scale extended, according to D. Wechsler, the diagnostic, possibilities of the battery is comparison with earlier intelligence, especially in the clinical sense. The test is of use between ages 10 to 59. The author suggests that the retest reliability of the whole test is 0.94.
3. The Wechsler Adult Intelligence Scale:
This is the 1955 revision of the Wechsler- Bellevue scale and is commonly known as WAIS. It is for ages 16 and above. The instrument has six subtests that constitute the verbal scale and five in the performance scale.
These are as follows: Information test the range of an individual’s information is an indication of his intellectual capacity General comprehension test success on this subtest depends upon possession of practical information, plus ability to evaluate and utilize past experience.
Arithmetical reasoning this is tie signed to test “mental alertness”. Similarities test it samples the “general factor” (Spear-man’s g), or what is commonly called general intelligence. Memory span for digits, forward and backward this is a test of immediate memory span and is helpful in detecting the mentally defective.
Vocabulary test it is helpful in deriving an index of a person’s general mental ability. Digit-symbol test also known as the substitution test, it requires the association of symbols, and involved speed and accuracy of performance.
It also involves visual memory. Picture completion tests it is valuable in testing lower level intelligence. It measures the individual’s basic perceptual and conceptual abilities. In a broad sense it measures the ability of the individual to differentiate essential from nonessential details. Block design tests performance on this test involves visual analysis and synthesis.
It measures a person’s ability to comprehend and evaluate a total situation without the use of language. Finally the Object assembly test it requires perception of parts and their reconstruction into a meaningful whole. It has clinical value of a qualitative kind; for it contributes to the examiner’s understanding of the subject’s modes of perception, the degree to which he relies upon trial-and-success methods, and the manner in which he responds to his errors.
The Wechsler Intelligence Scale for children (WISC) is from 5 through 15 years of age. It was developed in 1949 on the same principles and in the same form as the WAIS: verbal subtests, performance subtests, a verbal IQ, a performance IQ, and a full-scale IQ.
The subtest types are identical with those of the older scale, with the exceptions that follow: Digit span is made optional; an optional maze test has been added; and in place of the Digit symbol test, a coding test has been substituted, in which various lines in varied positions (single, double, circle) are associated with geometric figures (star, circle, triangle, cross, rectangle).