Although they spend most of their day in school, their ability to concentrate on classwork, make decisions, solve problems, retain (remember) information, and cope with exam stress is decreased. People may argue that to solve the problem, young people should go to bed earlier, but experts disagree. They say that there is a biological reason why teenagers go to bed late. As they grow and develop, they experience Sleep Phase Delay: they naturally fall asleep later and wake up later.