Students have sometimes found that after a good night's sleep they are able to remember material they studied the night before. Is this true?
So how many minutes or hours pass during a dream? Find out on this Moment of Science.
Almost all mammals, in fact, have REM sleep; birds do too, although only in the early parts of their lives. It seems that sleep and REM are required by a particularly complex kind of brain.
Sleep is divided into distinct cycles that contain four different types, or stages, of sleep. You experience stage one when you doze off at the office in the late afternoon, but you’re still aware that you’re sitting in front of your computer.