Dartmouth study looks at adult brain development

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(Host) A study by two Dartmouth College researchers sheds new light on what it means to be an adult, from the standpoint of brain development.

As VPR’s Steve Zind reports, the study is part of a relatively new field that explores how we change from adolescents to adults.

(Zind) Dartmouth College Senior Dan Moynihan says his freshman year stands out as unique in his life.

(Moynihan) "It was a gigantic period of adjustment!"

(Zind) Just about anyone who’s been a college freshman would probably have a similar assessment, but Moynihan is a psychology major, so he takes it a step further.

(Moynihan) "Becoming a completely different person has to correspond to something biological."

(Zind) A similar thought led Dartmouth assistant professor Abigail Baird and graduate student Craig Bennett to embark on a study of a group of 18-year-olds at the college. They used magnetic resonance imaging to track changes in the students’ brains.

Baird says the results show a dramatic burst of brain development between fall and spring of freshman year.

The changes were concentrated in the white matter, which is essentially the wiring that connects various parts of the brain. Baird says the wiring developed significantly in areas of the brain responsible for how we respond emotionally to what’s happening around us and inside us.

For example, Baird says increased white matter in section of the brain known as the insula heightened the student’s awareness about signals being sent by the body.

(Baird) "Say you have a stomach ache. The insula, together with some other brain regions helps you to figure out, is that stomach ache from food poisoning or is that stomach ache because you feel guilty about something?’ If your muscles are tense, is it because you’re angry or is it because you worked out yesterday?"

(Zind) Baird says an increasing ability to understand how and why we’re responding to something is a sign of a brain that is transitioning from adolescence to adulthood. She says largely because of cultural factors this transition occurs much later in Americans.

(Baird) "The United States drags puberty on forever. Most countries see adulthood as around sixteen or seventeen and they’ve prepared their young people to be adults by that point and we just don’t."

(Zind) Baird says there’s been extensive research on brain changes in children and in adults, but the eighteen to twenty-five age group hasn’t been studied nearly as much. Continued research could change how we define adulthood.

Look at the voting age and the drinking age. Each takes a different view of what constitutes adulthood.

(Baird) "The most interesting definition of adulthood is the one that the auto insurance industry has: twenty five. They know the odds and have been calculating the odds for years and years and so they say, there’s a certain type of maturity that comes in this time and place in this country after twenty-five."

(Zind) Baird says there’s nothing to indicate the dramatic brain changes in 18-year-olds are limited to college students. She says the next step would be to study people leaving home to enter the military or take a new job.

For Vermont Public Radio, I’m Steve Zind at Dartmouth College.

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