Excerpted from AQ: A New Kind of Intelligence for a World That’s Always Changing by Liz Tran, in agreement with Crown Currency, an imprint of The Crown Publishing Group, a division of Penguin Random House LLC. Copyright © 2026 by Liz Tran. When France began mandatory education for all children in the late 1800s, it required a way to assess the “mental age” of students to properly place them in the right classrooms. Two French psychologists, Alfred Binet and Théodore Simon, leaped at the invitation and created the first-ever practical intelligence test. Since then, the Binet-Simon Intelligence Scale has inspired countless other researchers, including Lewis Terman, who transformed the original framework into the Stanford-Binet Test, the standard IQ assessment in the United States for most of the 20th century. Terman believed that high IQ indicated genius, and he sought to prove this with a study he launched in 1921 that tracked 1,528 kids with IQ scores over 135, following them for their entire lives as they grew from children to adults, with the research ending only …