The more we work, the more we juggle a constant bombardment of tasks, the brighter we become.

This is the thinking of Northeastern University’s distinguished professor of economics and social policy William T. Dickens, a former Russell-Sage Foundation scholar, current nonresident senior fellow at the Brookings Institution, and an expert on IQ.

Dickens, who joined the Northeastern faculty this year and will work closely with the School of Social Science, Urban Affairs and Public Policy, received his doctorate in economics from MIT.

Throughout his storied research career, Dickens has examined a wide range of topics, from the macroeconomics of low inflation to international comparisons of wage flexibility. But his research focus as of late, on the malleability of cognitive ability—the ability to change IQ in an individual, and across generations—has captured his imagination.

“The idea is that the brain is very plastic, and it may be able to change to increase or decrease IQ, depending on how it’s used,” Dickens said.

“For example, people working in jobs with a lot of demands, who have had to learn certain complicated tasks, may be able to increase the capacity of their brains. We know, for example, that when people learn to juggle, the amount of gray matter in the relevant parts of their brains increases, and the same may be true for the part of the brain that stores maps in long-time taxi drivers, for example.”

By contrast, Dickens said, research shows that those who enter retirement generally experience a dip in IQ, although it is not known whether failing health or other issues contributed to that drop.

Dickens began studying IQ 15 years ago, when the Clinton administration asked the Brookings Institution for a briefing on the implications of the controversial 1994 book on IQ, The Bell Curve, for its workforce policies. Dickens, who had just come from serving as a senior economist with the President’s Council of Economic Advisors, was asked to do the briefing.

The briefing became an article in The Brookings Review and that article caught the attention of IQ expert James Flynn, a professor emeritus at the University of Otago in New Zealand, who is best known for his finding that the average IQ of populations all over the world has increased by 15 points with each generation. “He found that people are scoring higher on IQ tests today than their parents or grandparents,” Dickens said.

Dickens has coauthored several articles with Flynn, examining various factors affecting IQ, including race and social disadvantage. Increasingly, he has come to believe that IQ in populations has
changed as workforce demands have shifted.

“If you look back 100 years at the fraction of people who were in
professional managerial jobs, technical jobs, and compare it to today,
you’ll see a dramatic difference,” he said. “The numbers of people engaged in daily problem solving, and intense thinking as part of their work has gone up enormously.

“Compare that to the work, mostly manual labor, that used to be such a large part of our economy, and I believe we’re seeing a correlation between our work and the increase in overall IQ that James
Flynn has found.”