Why do we sleep? Well... that's a tricky question. More easily answered is the question, "How do we sleep?" In this episode of Crash Course Psychology, Hank discusses some of the ways our brain functions when sleeping and how it can malfunction as well. Want more videos about psychology? Check out our sister channel SciShow Psych at null! -- Chapters: Introduction: What Happens When We're Sleeping? 00:00 What is sleep and why do we do it? 1:20 How do we sleep? 1:56 Rapid Eye Movement (REM) 2:38 4 Stages of Sleep 3:08 Sleep Deprivation 4:28 Sleep Disorders 4:47 What do we dream about? 6:08 Why do we dream? 7:26 Review & Credits 9:46 -- Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse Want to find Crash Course elsewhere on the internet? Facebook - http://www.facebook.com/YouTubeCrashCourse Twitter - http://www.twitter.com/TheCrashCourse Instagram - https://www.instagram.com/thecrashcourse/ CC Kids: null