In 1905 two Frenchmen, Alfred Binet (1857–1911) and Theophil Simon (1873–1961), invented the IQ (Intelligence Quotient) test to distinguish between mentally retarded and normal school children. They set tasks that normal children could do; for example, five-year-olds were asked to compare two weights, copy a square, repeat a sentence of ten syllables, count four pennies, and unite the halves of a divided rectangle.

By 2005 there were thousands of tests but two have special significance. The first, Raven's Progressive Matrices, measures on-the-spot problem solving where no previously learned method is applicable. It presents a pattern of shapes from which one piece is missing, offers six alternative missing pieces, and then asks the examinee to choose the correct one (Raven 2000). The second, the Wechsler Intelligence Scale for Children (WISC), supplements Raven's by using ten to twelve subtests to measure a variety of cognitive skills. These tests constitute technologies that raise significant...