August 25, 2009
More Developed Brain White Matter In Risk Taking Teens

Teenagers who take more risks have more adult-like brains as measured by white matter.

A new study using brain imaging to study teen behavior indicates that adolescents who engage in dangerous activities have frontal white matter tracts that are more adult in form than their more conservative peers.

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 this delayed brain maturation is the cause of impulsive and dangerous decisions in adolescence. The new study, using a new form of brain imaging, calls into question this theory.

In order to better understand the relationship between high risk-taking and the brain's development, Emory University and Emory School of Medicine neuroscientists used a form of magnetic resonance imaging (MRI) called diffusion tensor imaging (DTI) to measure structural changes in white matter in the brain. The study's findings are published in the Aug. 26, 2009 PLoS ONE.

Why do you suppose that is? I'd like to know whether the teens whose white matter develops more quickly have more testosterone. Does testosterone speed brain development while also increasing risk-taking behavior?

Share |      Randall Parker, 2009 August 25 11:18 PM  Brain Development

Lono said at August 26, 2009 8:19 AM:


I read a very good article in Scientific American a while back whose explanation, I believe, may help shed some light on this unintuitive correlation.

Basically impulsive and risk taking behavior in teens is now seen simply as a matter of overthinking it - the teens are actually being too analytical in analyzing risk and reward to various behaviors.

This is especially prevelent in those teens who have developed more adult like brains at an earlier age - as they are very proned to over analyzing a situation.

Adults are somewhat less likely to engage in impulsive and risky behavior precisely because older brains abstract data more efficently and analyze specific data points less efficently.

For example - an intelligent, middle class, white teen may look at the facts and find it very unlikely that unprotected sex within their community will lead them to acquiring Aids - as the odds based on statistics they have been taught in health class shows this group as especially low risk - so they go ahead an engage in this "risky" behavior.

An intelligent adult, however, is more likely to abstract the risks - and not being confidently aware of the specific odds - will err on the side of caution and say that any risk of getting Aids through unprotected sex - with a new partner - is unacceptable - no matter how low the odds really are for their demographic.

I was an exceptionally bright child (Straight A's, Honors/AP classes, Gainfully employed) who engaged in expeceptionally risky behavior for the same reasons - I felt confident I understood the odds - and I remember, around, 22 taking a very different attitude - after many of my former classmates died due to various misadventure - and deciding to take a much more conservative approach to risk taking - cutting out most behaviors that had any significant risk of death or dismemberment - and becoming much more law abiding to also prevent any risk of incarceration.

This, I strongly feel, was due to the greater abstraction of risk - that occurs as gray matter begins to stagnate and decline - while white matter - continues to grow and dominate - presenting a bigger, more abstract, understanding of one's life and environment.

(white matter accomplishes this by creating greater inter-connectivity in the brain, causing memory, emotion, and logic to be better integrated in decision making - what we commonly refer to as the wisdom of old age)

Although in this study the early formation of white matter is discussed - I think it is still too immature to allow for significant abstraction - (as Gray Matter still dominates) - but rather just increased efficiency of brain processing of specific data.

(Thus the Gray Matter is even more analytical in it's newly increased connectivity)

Really interesting stuff imho - and yet another way in which an artificial brain will be a very different creation.

no said at August 26, 2009 9:52 AM:

But surely this is not an unintuitive correlation?
At preschool/kindergarten age those who are more active at exploring their surroundings are more likely to develop faster than those kids whose parents are very overprotective.
Is this case with teenagers not simply the same thing at a more advanced stage, they are pushing their luck, testing their limits and stretching themselves in the process.
I bit like the Robot from Short Circuit 1&2 "Jonny 5" who kept looking for 'input'.

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