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Adolescent Brains Biologically Wired to Engage in Risky Behaviors

There are biological motivations behind the stereotypically poor decisions and risky behavior associated with adolescence, new research from a University of Texas at Austin psychologist reveals.

Previous studies have found that teenagers tend to be more sensitive to rewards than either children or adults. Now, Russell Poldrack, PhD, a professor in the departments of psychology and neurobiology, and fellow researchers have taken the first major step in identifying which brain systems cause adolescents to have these urges and what implications these biological differences may hold for rash adolescent behavior.

“Our results raise the hypothesis that these risky behaviors, such as experimenting with drugs or having unsafe sex, are actually driven by over activity in the mesolimbic dopamine system, a system which appears to be the final pathway to all addictions, in the adolescent brain,” Poldrack says.

In the study, participants ranging in age from 8 to 30 performed a learning task in which they categorized an abstract image into one of two categories and were given feedback displaying the correct response. To ensure motivation, they were given monetary rewards for each correct answer.

What the researchers were most interested in, however, was how each participant’s brain responded to “reward prediction error” (or the difference between an expected outcome of an action and the actual outcome) as they learned to categorize the images.

Researchers measured so-called positive prediction error signals in the participants’ brains as the participants discovered the results of their answers and the size of their rewards. Teenagers showed the highest spikes in these prediction error signals, which likely means they had the largest dopamine response.

Poldrack is confident future studies will further explore the biological reasons for stereotypical adolescent behavior. As to whether any study can absolve teens of blame for their antics, he says, “That’s a question for the philosophers.”

— Source: University of Texas at Austin