The brain goes through a course of maturation during adolescence and does not reach its adult form until the mid-twenties. A long-standing theory of adolescent behavior has assumed that delayed brain maturity is the cause of impulsive and dangerous decision making. A new study, using a new form of brain imaging, calls into question this theory.
“In the past, studies have focused on the pattern of gray matter density from childhood to early adulthood, says Gregory Berns, MD, PhD, principal investigator and professor of Psychiatry and Neuroeconomics at Emory University and director of the Center for Neuropolicy. “With new technology, we are able to develop the first study looking at how development of white matter relates to activities in the real world.”
Gray matter is the part of the brain made up of neurons, while white matter connects neurons to each other. As the brain matures, white matter becomes denser and more organized. Gray matter and white matter follow different trajectories. Both are important for understanding brain function.
A study enrolled 91 adolescents ages 12 through 18 over a three-year period. A form of magnetic resonance imaging (MRI) called diffusion tensor imaging (DTI) was used to measure structural changes in white matter in the brain. Levels of engagement in dangerous behaviors were measured by a survey that included questions about the teens’ thrill seeking behaviors, reckless behaviors, rebellious behaviors and antisocial behaviors. The outcome showed that risk-taking was associated with more highly-developed white matter – a more mature brain,” says Berns. “We were also surprised to learn that except for slightly higher scores in risk-taking, there was no significant difference in the maturity of the white matter between males and females.”
Berns suggests that doing adult-like activities requires sophisticated skills. “Society is a lot different now than it was 100 years ago when teens were expected to go to work and raise a family,” says Berns. “Now, adolescents aren’t expected to act like adults until they are in their twenties, when they have finished their education and have found a career.
You could make the case that in this country, biological capacity shows up long before wisdom, which is fully developed over time. Berns states that more studies need to be done to determine if early brain development predisposes someone to engage in risky behaviors, or if the risky behavior drives the maturation of the brain.
The CDC reports that, 27,000 people between the ages of 10 and 24 die from bad decisions in the United States per year. Additionally, it has been shown that the period of mid-adolescence (ages 15 through 19) is the time when teens are more likely to begin high-risk behaviors such as drinking, abusing drugs or driving recklessly.
When teenagers engage in risky behavior, adults usually chalk it up to some innate fondness for risk — the thrill of an unsafe situation. But in fact, their willingness to engage in risky behavior may have less to do with thrill-seeking per se than with a higher tolerance for uncertain consequences. A research report from New York University suggests that teenagers enter unsafe situations not because they are drawn to dangerous or risky situations, but rather because they aren’t well informed about the consequences of their actions.
Some of the content for this article was comprised from the following website: http://www.sciencedaily.com/releases/2009/08/090825203341.htm
