AP PSYCHOLOGY

Detailed explanation-1: -These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.

Detailed explanation-2: -Stage 4: REM sleep In REM sleep, your brain waves and eye movements increase. Your heart rate and breathing also speed up. Dreaming often happens during REM sleep. Your brain also processes information during this stage, making it important for learning and memory.

Detailed explanation-3: -Stages 3 and 4, Slow-Wave Sleep Sleep stages 3 and 4 are collectively referred to as slow-wave sleep (SWS), most of which occurs during the first third of the night. Each has distinguishing characteristics. Stage 3 lasts only a few minutes and constitutes about 3 to 8 percent of sleep.

Detailed explanation-4: -In stage 1, you transition from wakefulness to sleep. In stage 2 you enter light sleep. By stage 3 you are in a deep sleep. Stage 4 REM, known as paradoxical sleep, is when the body’s immobilized and dreams occur.

Detailed explanation-5: -Stage 2 of non-REM sleep During stage 2, the heart rate and breathing regulate, the body temperature goes down, the eye movements either slow or stop completely.