People too often forget that IQ tests haven’t been around that long. Indeed, such psychological measures are only about a century old. Early versions appeared in France with the work of Alfred Binet and Theodore Simon in 1905. However, these tests didn’t become associated with genius until the measure moved from the Sorbonne in Paris to Stanford University in Northern California. There Professor Lewis M. Terman had it translated from French into English, and then standardized on sufficient numbers of children, to create what became known as the Stanford-Binet Intelligence Scale. That happened in 1916. The original motive behind these tests was to get a diagnostic to select children at the lower ends of the intelligence scale who might need special education to keep up with the school curriculum. But then Terman got a brilliant idea: Why not study a large sample of children who score at the top end of the scale? Better yet, why not keep track of these children as they pass into adolescence and adulthood? Would these intellectually gifted children grow up to become genius adults?
Terman subjected hundreds of school kids to his newfangled IQ test. Obviously, he didn’t want a sample so large that it would be impractical to follow their intellectual development. Taking the top 2 percent of the population would clearly yield a group twice as large as the top 1 percent. Moreover, a less select group might be less prone to become geniuses. So why not catch the crème de la crème?