STREET DOGS

From Faye Flam at BloombergView: How much is success determined by innate intelligence? Economist James Heckman says it’s not what people think. He likes to ask how much of the difference between people’s incomes can be tied to IQ. Most guess about 25%, even 50%, he says. But the data suggest a much smaller influence: about 1% or 2%.

So if IQ is only a minor factor in success, what separates the low earners from the high ones? Science doesn’t have a definitive answer, although luck plays a role.

But another key factor is personality. He found financial success was correlated with conscientiousness, a personality trait marked by diligence, perseverance and self-discipline.

To reach that conclusion, he examined four data sets, which included IQ scores, standardised test results, grades and personality assessments for people in the UK, 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 “noncognitive 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.

But it’s not always clear whether more of a trait is better. The higher the better for IQ and perhaps for conscientiousness as well. But personality researchers have suggested the middle ground is best for other traits — you don’t want to be so introverted that you can’t speak up, or so extroverted that you can’t shut up and listen.