The further development was an instrument to measure Intelligence by American psychologist David Wechsler. Wechsler also believed that intelligence involved a no. of different mental abilities, describing intelligence as, "the global capacity of a person to act purposefully, to think rationally, and to deal effectively with his environment" (1939).
He wasn’t satisfied with the limitations of the Stanford Binet’s test, so he published his new intelligence test which was known as the Wechsler Adult Intelligence Scale (WAIS) in 1955. In early 1960’s, he outstrip the Stanford Binet and slowly became very popular. It has been revised many times, as is common for IQ tests, to incorporate new research. Wechsler tests …show more content…
The Wechsler test includes three age-specific tests:
• Wechsler Preschool and Primary Scale of Intelligence (WPPSI): children ages 2 to 7
• Wechsler Intelligence Scale for Children (WISC): children 6 to …show more content…
The WAIS-IV contains 10 subtests with 5 supplemental tests.
The test provides scores in four major areas of intelligence:
1. A Verbal Comprehension Index.
2. A Perceptual Reasoning Index.
3. A Working Memory Index.
4. A Processing Speed Index.
Rather than score the test based on chronological age and mental age. The test also provides two broad scores that may be used as a summary of overall intelligence: A combine’s performance on all four major areas of intelligence is a Full Scale IQ score and a General Ability Index based on six subtest scores.
WAIS is scored by comparing the score of test taker’s to the others in the same age group’s score. Average score 100 is fixed, with 2/3 of scores lying in the normal range 85 to 115. This scoring method has become the standard technique in intelligence testing and is also used in the modern revision of the Stanford-Binet test.
Categories of Intelligence Quotient score
IQ Scores are divided into main three categories are low, average and high. The average score on an IQ test is 100. Sixty-eight percent of IQ scores fall within one standard deviation of the mean. So it indicate that the large no. of people have an IQ score between 85 and