Brain Develops Risk Aversion Late

Brain immaturity can be deadly (MSNBC)

By most physical measures, teenagers should be the world’s best drivers. Their muscles are supple, their reflexes quick, their senses at a lifetime peak. Yet car crashes kill more of them than any other cause — a problem, some researchers believe, that is rooted in the adolescent brain. A National Institutes of Health study suggests that the region of the brain that inhibits risky behavior is not fully formed until age 25, a finding with implications for a host of policies, including the nation’s driving laws. “We’d thought the highest levels of physical and brain maturity were reached by age 18, maybe earlier — so this threw us,” said Jay Giedd, a pediatric psychiatrist leading the study, which released its first results in April. That makes adolescence “a dangerous time, when it should be the best.”

Last month, Sen. William C. Mims (R-Loudoun) cited brain development research in proposing a Virginia bill that would ban cell phone use in vehicles for drivers younger than 18. It passed Friday. In Maryland, Dels. Adrienne A. Mandel and William A. Bronrott said the research could bolster three bills the Montgomery County Democrats submitted to the legislature Friday. The bills would expand training and restrict passenger numbers and cell phone use for certain teenage drivers.

The measures also are supported by crash statistics and a soon-to-be released study from Temple University, which used a driving-style test to show that young people take greater risks consistently when their friends are watching. “This goes toward supporting evidence that the judgment of teens further deteriorates with distractions. These crashes are preventable,” Mandel said. “I would welcome [researchers’] testimony at our bill hearings.”

It’s not surprising that young people are less cautious than grown-ups, although the brain development angle is news to me.

Pejman Yousefzadeh observes,

If true, I find this bizarre. The interest of the species in surviving would intuitively lead to a conclusion that risk-taking would be augmented as one grows older and comes closer to death. In a perfectly logical order of things, the younger you are, the more appreciation you would have for risk, and the easier it would be for you to live to a ripe old age.

While that’s true, there’s certainly some societal advantage to the natural order. Fighting wars, hunting game, and similar endeavors require both a young body and a willingness to throw caution to the wind. It makes theoretical sense to send octogenarians out to do these tasks, on the theory that they’ve already lived full lives, but there are some serious practical limitations.

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James Joyner
About James Joyner
James Joyner is Professor and Department Head of Security Studies at Marine Corps University's Command and Staff College. He's a former Army officer and Desert Storm veteran. Views expressed here are his own. Follow James on Twitter @DrJJoyner.


  1. caltechgirl says:

    Well, here’s the thing. The part of our brains that is responsible for planning and executive function, which are the other components of risk aversion (beyond simple fear), the prefrontal cortex, doesn’t reach full maturity until late teens, early twenties. Sure, it works your whole life, but in the teens it undergoes a pretty extensive reorganization (called pruning) and a whole different series of connections and influences underlie the same functions in adulthood.

  2. bryan says:

    Pejman clearly isn’t thinking quite as “logically” as he thinks he is. Logically, someone who is older has much more invested in his/her life, including children and significant relationships and therefore is less likely to take risks that would put those who depend on him/her in greater danger.

    The survival of the species angle isn’t really relevant, because it’s the survival of the species, not every individual member of the species.

  3. Garrett says:

    Our expectation of living into the eight decade is not the conditions that we developed under. In primative societies the average life is about 40 yr at best with a small percentage living beyond to act as a leavening aginst the excess of the young. This is the way that societal memory is transferred forward. It is unlikely, under these conditions that the old would be assigned ( naturally, or culturally) the high risk tasks.

  4. Dave Schuler says:

    Explain to me again why extending the franchise to 18 year olds was a good idea.