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.”