A Frenchman, the psychologist Alfred Binet, published the first standardized test of human intelligence in 1905. But it was an American, Lewis Terman, a psychology professor at Stanford, who thought to divide a test taker's 'mental age', as revealed by that score, by his or her chronological age to derive a number that he called the 'intelligence quotient', or IQ. It would be hard to think of a pop-scientific coinage that has had a greater impact of the way people think about themselves and others. No country embraced the IQ--and the application of IQ testing to restructure society--more thoroughly than the U.S.. Every year millions of Americans have their IQ measured, many with a direct descendant of Binet's original test, the Stanford-Binet, although not necessarily for the purpose Binet intended. He developed his test as a way of identifying public school students who needed extra help in learning, and that is still one of its leading uses. But the broader and more controversial use of IQ testing has its roots in a theory of intelligence--part science, part sociology --that developed in the late 19th century, before Binte's work and entirely separate from it. Championed first by Charles Darwin' s cousin Francis Galton, it held that intelligence was the most valuable human attribute, and that if people who had a lot of it could be identified and put in leadership positions, all of society would benefit. Terman believed IQ tests should be used to conduct a great sorting out of the population, so that young people would be assigned on the basis of their scores to particular levels in the school system, which would lead to corresponding socioeconomic destinations in adult life. The beginning of the IQ-testing movement overlapped with the eugenics movement--hugely popular in America and Europe among the 'better sort' before Hitler gave it a bad name--which held that intelligence was mostly inherited and that people-deficient in it should be discouraged from reproducing. The state sterilization that Justice Oliver Wendell Holmes notoriously endorsed in a 1927 Supreme Court decision was done with an IQ score as justification. The American IQ promoters scored a great coup during World War I when they persuaded the Army to give IQ tests to 1.7 million inductees. It was the world's first mass administration of an intelligence test, and many of the standardized tests in use today can be traced back to it: the now ubiquitous and obsessed-over SAT(Study Ability Test) the Wechsler, taken by several million people a year, according to its publisher and Terman' s own National Intelligence Test, originally used in tracking elementary school children. All these tests took from the Army the basic technique of measuring intelligence mainly by asking vocabulary questions (synonyms, antonyms, analogies, reading comprehension). According to Termon's theory, a twelve-year-old boy's mental age is 10, then his IQ number is about______.