Why do teenagers sometimes make outrageous, risky choices? Do they suddenly become reckless, or are they just going through a natural phase? To find out, Kashfia Rahman -- winner of the Intel International Science and Engineering Fair (and a Harvard freshman) -- designed and conducted an experiment to test how high school students respond to and get used to risk, and how it changes their still-developing brains. What she discovered about risk and decision-making could change how we think about why teens do what they do.

How risk-taking changes a teenager's brain

Teenagers become more prone to risky behaviors not just because their brains are still developing, but because repeated exposure to risk actually shifts their emotional responses. A high school experiment with 86 students showed that the more teens faced risky choices, the less fear and guilt they felt, making them likelier to take even bolder risks. This process, called habituation, physically alters how the brain reacts to danger and temptation. Understanding this shift can help parents, educators, and teens address the roots of escalating risk, not just the symptoms.