User:Yaduvanshi Kumar

government polytechnic colleges chauck by wilipedia The first modern-day IQ test was created by Alfred Binet in 1905. Unlike Galton, he was not inspired by scientific inquiry. Rather, he had very practical implications in mind: to be able to identify children who cannot keep up with their peers in the educational system that had recently been made compulsory for all.

Binet’s test consisted of knowledge questions as well as ones requiring simple reasoning. Besides test items, Binet also needed an external criterion of validity, which he found in age. Indeed, even though there is substantial variation in the pace of development, older children are by and large more cognitively advanced than younger ones. Binet, therefore, identified the mean age at which children, on average, were capable of solving each item, and categorized items accordingly. This way he could estimate a children’s position relative to their peers: if a child, for instance, was capable of solving items that were, on average, only solved by children who were two years older, then this child would be two years ahead in mental development.

William Stern

Subsequently, a more accurate approach was proposed by William Stern, who suggested that instead of subtracting real age from the age estimated from test performance, the latter (termed 'mental age') should be divided by the former. Hence the famous 'intelligence quotient' or 'IQ' was born and defined as (mental age) / (chronological age). It indeed turned out that such a calculation was more in line with other estimates of mental performance. For instance, an 8-year-old