The major difference is that children reach this agitated sleep state faster than adults do and remain in it longer. Many people had observed the restless eye movements of sleepers, but no one had recognized the regularity of the twitches or had tried to understand their significance. Once the news was out other researchers confirmed the phenomenon, and it was formally named rapid eye movement, or REM sleep. The next obvious step was to find out exactly what purpose REM sleep served. Aserinsky and Kleitman guessed that the eye movements might be linked to dreaming, so they decided to put their hunch to the test in their sleep-research laboratory. Volunteers agreed to sleep in the lab and allow researchers to wake them randomly. Sleepers awakened during REM sleep were more likely to recall a dream and give a longer narrative of what they had experienced than those awakened during non-REM sleep. (Dowling 180) The connection between rapid eye movement and dreaming seemed clear. Studying the peaks and valleys inked on rolls of graph paper by the electroencephalograph's mechanical pens, researchers determined that brain waves fall into several general groups. They also noticed that the brain descends through four stages of non-REM sleep, each characterized by a different wave or combination of waves. .
When a person falls asleep for the first time at night, his or her eyes remain fairly relaxed for about 45 minutes as the brain moves deeper and deeper, through all the stages of sleep. (Rose 42) Then the process reverses itself, and the sleeping brain moves back up through the levels. But then, instead of ascending from stage 2 into stage 1, the brain shifts into a different phase. At this point pens recording eye movements jerk across the page and the mysterious REM period begins. REM sleep initially lasts for only twenty minutes, and the deep sleep recurs. REM sleep recurs for a longer period of time and is followed by another phase of a deeper level of sleep.
