The major breakthrough in the study of dreams came in 1953 when researchers Eugene Aserinsky and Nathaniel Kleitman studied and discovered what happens when a person falls asleep.They found that the body enters into a psycho-physiological state in intervals of 90 minute cycles during sleep. This physiological state consists of heightened brain activity, Rapid Eye Movement (REM), increased breathing, a temporary paralysis of the body and genital engorgement. Through experiments, they confirmed that these physiological observations were the result of the person being in the dream state.