Can an Entire Generation Change Its Personality?



See the column on the Wall Street Journal site

When the cartoon character Popeye proclaims, “I yam what I yam,” he personifies the idea that personality traits are more or less fixed in adulthood. Whether shy or outgoing, a leader or a follower, we are—notwithstanding minor tweaks—who we are.

But what if a whole generation can learn a new set of tricks?

A new study suggests as much. Published this month in the Proceedings of the National Academy of Sciences, the research shows a shift in many personality traits in men that could make them more successful in the workplace. This huge study included 80% of the male population born in Finland between 1962 and 1976, or 419,523 young men. All of them had taken standardized cognitive and personality tests when they entered the Finnish Defense Forces under a compulsory male draft at the age 19 or 20.

The researchers then looked at these Finnish men’s average annual earnings at age 30 to 34, which the scientists considered a good predictor of their lifetime earnings.

What struck researchers the most was that self-confidence, sociability and leadership motivation all rose on average from the group of men born in 1962 to those born in 1976. Striving, deliberation and dutifulness crept up too, though not as much. Levels of intelligence or family income didn’t seem to be driving these generational shifts, given that they surfaced at all cognitive levels and social strata.

And here’s the kicker: When the researchers compared personality scores when the men entered the draft with earnings at age 30 to 34, they found that even small upward shifts in personality ratings predicted a higher income 10 years later—with the 1976 group earning as much as 12% more than its 1962 counterpart, when other factors such as inflation, overall wage rises and education were stripped away.

“We don’t want to say that personality improves, because reasonable people can perfectly well disagree on what constitutes a good personality,” wrote Matti Sarvimäki, one of five authors of the study and an economist at Aalto University in Finland. “What we show is that the types of personality traits that predict higher earnings rise” from birth year to birth year.

Of course, we should be cautious when extrapolating from the experience of Finland, a country of about 5.5 million people, to the U.S. Nor is it clear whether these results would have a positive effect on the American labor pool. In addition, the Finnish study, due to the male-only draft, was limited to men.

Still, this study’s findings line up with some other positive trends. U.S. college students have become more outgoing, self-confident and self-absorbed—though that last trait may not be quite as positive as the others. Another rising measure: IQ scores are improving about three points a decade, a phenomenon known as the Flynn effect.

As with IQs, we don’t know why personality traits are changing. “It’s kind of a mystery,” says Richard Haier, an emeritus professor at the University of California, Irvine, and the author of “The Neuroscience of Intelligence.”

If extraversion is rising, he said, then—as is the case with IQ-test levels—improvements in general health and nutrition could be affecting the change. Education too could play a role, he says—for example, more exposure to problem-solving at school. Indeed, education is one of the factors Prof. Sarvimäki will explore next.