Teens are notorious for
taking more risks than adults, and a new imaging study suggests it's because
the adolescent brain is hyper-motivated when it comes to receiving rewards.
A study published online in Proceedings of the National Academy of Sciences suggests that
teen brains showed more activity in a specific pleasure centre of the brain
compared to adults when they were rewarded during gambling games where money
was at stake.
receiving a financial reward produced strong activity in a brain region called
the ventral striatum, especially in adolescents," said study author
Adriana Galvan, an assistant professor of psychology, behavioural neuro-science
and developmental psychology at the University of California, Los Angeles.
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For the study, Galvan and
her colleagues examined brain cell activity in the brains of 19 adults and 22
teens using functional magnetic resonance imaging (fMRI) while the study
participants played betting games that included modest monetary rewards –
final wins never tallied more than $40.
The teenagers were 13 to 17
years old, and the average age of the adults was 28. Each performed gambling
tasks. In each trial, the participants decided whether or not to accept or
reject a bet that had a 50% chance of resulting in a win or a 50%
chance of ending in a loss – so the trials were completely based on chance,
The fMRI images monitored
brain activity during the betting, and the authors reported that the ventral
striatum showed greater activity in teenagers than in adults during the
betting. Galvan said the increased brain activity in the teens showed they
valued the anticipated payoff more than the adults did, even during the trials
in which both age groups accepted the same bets.
Unique developmental changes
The reward-sensitive brain
regions in the teens were hyperactive compared to the adult brains. There are
unique developmental changes going on in their neural circuits, the researchers
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"We don't see this in
studies of younger kids either," said Galvan. "In a previous study we
published of younger children, they didn't have the same neuro-sensitivity to
rewards that we see in adolescents."Galvan also noted that the
greater activation in the teen brains, when it came to reward-earning, was
associated with making better choices in the game.
"The adolescents were
better able to pick up on the risks that were beneficial – that were worth
taking. We don't know why. They were just more responsive to the rewards,"
the author said.
Not always without logic
Galvan said the research
may help begin to change the way parents and other adults view teens'
risk-taking choices. Maybe those choices, while dicey at times, may not always
be without logic, she said.
"What we hope these
data do is start to change the conversation about the fact that being hypersensitive
to rewards during adolescence is not necessarily negative," said Galvan.
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"Sometimes that gets
spun – that being sensitive to rewards at this time in life may lead to bad
outcomes, like use of drugs," she noted. "But if the rewards go the
other way – helping to volunteer, getting a thrill from a soccer game –
that's something that can be advantageous to helping them become well-adjusted
Wolf said it's early yet,
though, to offer parenting advice based on these results. "At this point,
such studies don't have strong implications for parenting advice. I think that
what parents already know about teenagers has not been superseded, but studies
like this could help down the line," he said.
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