In this national bestseller, acclaimed, award-winning psychologist Dr. David Walsh explains exactly what happens to the human brain on the path from childhood into adolescence and adulthood. Revealing the latest scientific findings in easy-to-understand terms, Dr. Walsh shows why moodiness, quickness to anger and to take risks, miscommunication, fatigue, territoriality, and other familiar teenage behavior problems are so common -- all are linked to physical changes and growth in the adolescent brain. Why Do They Act That Way? is the first book to explain the changes in teens' brains and show parents how to use this information to understand, communicate with, and stay connected to their kids. Through real-life stories, Dr. Walsh makes sense of teenagers' many mystifying, annoying, and even outright dangerous behavioral difficulties and provides realistic solutions for dealing with everyday as well as severe challenges. Dr. Walsh's techniques include, among others: sample dialogues that help teens and parents talk civilly and constructively with each other, behavioral contracts, and Parental Survival Kits that provide practical advice for dealing with issues like curfews, disrespectful language and actions, and bullying. With this arsenal of strategies, parents can help their kids learn to control impulses, manage erratic behavior, cope with their changing bodies, and, in effect, develop a second brain.