In the century since standardized intelligence and achievement tests were first introduced, they have gained and lost favor many times both among education experts and among the general public. Some experts insist that some form of testing is necessary to evaluate both inborn intelligence and achievement in school; others claim that such tests must always contain prejudice of some sort, and that, at best, they discover who is most skilled at taking the tests.

The idea of testing children and adults to determine their level of intelligence or education grew out of the same scientific spirit that fueled the theory of evolution and inherited characteristics proposed by Charles Darwin (1809–1892) during the late nineteenth century. As scientists began to believe that some qualities were passed from one generation to another, the idea took hold that intelligence was one of those inherited qualities. In the late 1800s, a...