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 non-scientists -especially politicians and policymakers -how much of the difference between people’s incomes can be tied to IQ. Most guess around 25%, even 50%, he says. But the data suggest a much smaller influence: about 1or 2%.
So if IQ is only a minor factor in success, what is it that separates the low-earners from the high ones?
Science doesn’t have a clear answer, although luck certainly plays a role. But another key factor is personality , according to a paper Heckman co-authored in the `Proceedings of the National Academy of Sciences’ last month.He found financial success was correlated with conscientiousness, a personality trait marked by diligence, perseverance and self-discipline.
To reach that conclusion, he and colleagues examined four different data sets, which, between them, included IQ scores, standardised test results, grades and personality assessments for thousands of people in the UK, the US and the Netherlands. Some of the data sets followed people over decades, tracking not just income but criminal records, body mass index and self-reported life satisfaction.
The study found that grades and achievement-test results were markedly better predictors of adult success than raw IQ scores. That might seem surprising -after all, don’t they all measure the same thing? Not quite.Grades reflect not just intelligence but also what Heckman calls “non-cognitive skills“, such as perseverance, good study habits and the ability to collaborate -in other words, conscientiousness. To a lesser extent, the same is true of test scores.Personality counts. Heckman, who shared a Nobel Prize in 2000, believes success hinges not just on innate ability but on skills that can be taught. Openness -a broad trait that includes curiosity -is also connected to test scores and grades.
IQ still matters, of course.Someone with an IQ of 70 isn’t going to be able to do things that are easy for a person with an IQ of 190. But Heckman says many people fail to break into the job market because they lack certain skills -they don’t understand how to behave in interviews. Or on the job, they make it obvious they’ll do no more than the minimum, if that.