How much is a child's future success determined by innate intelligence? Economist James Heckman says it's not what people think. He likes to ask educated nonscientists — especially politicians and policymakers — how much of the difference between people's incomes can be tied to IQ. Most guess around 25 percent, even 50 percent, he says. But the data suggest a much smaller influence: about 1 or 2 percent.
So if IQ is only a minor factor in success, what is it that separates the low earners from the high ones? Or, as the saying goes: If you're so smart, why aren't you rich?
Science doesn't have a definitive answer, although luck certainly plays a role. But another key factor is personality, according to a paper Heckman recently co-authored in the Proceedings of the National Academy of Sciences. He found that financial success was correlated with conscientiousness, a personality trait marked by diligence, perseverance and self-discipline.