For a long time, most adults have assumed that teens take risks and act impulsively because their brains aren’t fully developed. It’s the explanation we hear a lot for their “immaturity.” And although some very reputable publishers have reported on the “teenage brain” – e.g., PBS Frontline, Harvard Magazine, and the National Institute of Mental Health – one academic researcher I know even calls this “pop science.” Well, a new study at Emory University really reinforces the pop-science perspective and could end up turning the developing-brain theory upside down. It found that “the brains of teens who behave dangerously are more like adult brains than are those of their more cautious peers,” Scientific American reports. At least two observations undermine the theory that the impulse-control, executive part of the brain develops later than the emotional part, it says: “First, American-style teen turmoil is absent in more than 100 cultures around the world, suggesting that such mayhem is not biologically inevitable. Second, the brain itself changes in response to experiences, raising the question of whether adolescent brain characteristics are the cause of teen tumult or rather the result of lifestyle and experiences.” Certainly nothing’s completely clear yet, but term “teenage brain” already feels dated and a little disrespectful.