For years, scientists believed that human brain development was completed by the time we were 10 or 11. Recent studies, however, show that during our teenage years, our brain is still maturing in important ways. When we’re teenagers, our decision-making ability is developing and we’re learning to make good choices. At the same time, we’re more likely than ever to take risks. Is this normal? Scientists who study the brain say “yes”. In fact, they believe that risk-taking and our “irrational” behaviors may actually help teens to become successful adults. Take, for example, the teenager’s love of thrills. We all like new and exciting things, but never as much as we do during our teenage years. During this time of our lives, scientists say, our brains produce chemicals that can lead to dangerous behaviors, and it can also produce positive ones. Taking risks and trying new things may be challenging or even dangerous, but this behavior can also lead to useful experiences that will benefit us as adults. Scientists also find there is an intense need for peer (同龄人) approval among teenagers. We enter a world made by our parents. But we will live most of our lives and succeed in a world run by our peers. Therefore, it is important that we are accepted and respected by our peers, even if it means taking some risks to fit it.