Know a teenager that has made a poor decision? Who doesn’t? Still, it may not be his or her fault. Adolescent brains appear to be engineered for risky behavior, according to a new study published in the journal Nature.

Functional magnetic resonance imaging (fMRI) was used to identify structural changes in the adolescent brain that corresponds to fluctuations in IQ. These findings may help explain why so many teens exhibit thrill-seeking behavior or seem so completely nonchalant about their own safety.

Research from the National Institutes of Health has already found that teens are more sensitive to rewards and less sensitive to risks. The prefrontal cortex, which helps inhibit risky behavior, is not fully developed in a person until about age 25. To make matters worse, when in the presence of friends, a teenager’s reward system is aroused even more, according to Laurence Steinberg, a professor of psychology at Temple University.

The good news is that because their brains are still developing, teens tend to be rapid learners – for example, they can pick up languages faster than adults. But they can also pick up dangerous habits more easily, too. It’s the reward-seeking teen brain that is easily drawn to pleasure-inducing substances such as drugs and alcohol.

Could there be an evolutionary or genetic reason for such a built-in mechanism that allows a young person to ignore potential dangers in the world?

"If it didn't happen, we wouldn't leave home and reproduce," Steinberg says.