Before dreams begin, a person goes through a sleep cycle. Eugene Aserinsky and Nathaniel Kleitman of the University of Chicago discovered the sleep cycle in 1953. (HowS) This discovery was made using electrodes. The electrodes were connected to test subjects at seven locations. Three electrodes recorded brain activity and brain waves, and two more recorded eye movements. An electrode was placed on the neck to record the vocal tone coming from the neck or any other sound coming from the subjects. A final electrode was placed on the chest to record heart rate. The results of this study showed that humans have five stages of sleep. (Book) Different lengths of time are spent on each of them, but the night is not distributed equally among the five stages. The first stage of sleep is very light sleep from which it is easy to wake up. Normally, only four to five percent of the night is spent on this step. The second stage is where body temperature drops and heart rate slows, and one begins to fall asleep more deeply. 45 to 55 percent of the night is spent on the second stage. Four to six percent of the night is spent transitioning into deep sleep, known as stage three. Deep sleep occurs during the fourth stage and approximately twelve to fifteen percent have passed into deep sleep. Sleepwalking and bedwetting usually occur at this stage because this is when the muscles begin to relax. The last stage of sleep is called the rapid eye movement stage, or REM sleep. Dreams occur primarily during REM sleep, and 20-25% of the night is typically spent in this stage. Throughout the night, humans do not go through all five stages even once. According to sleep studies, a typical sleep cycle goes from stage one to stage four, back to stages two and three, middle of paper...... showing the emotions one suppresses throughout of the day in their dreams. If someone thinks a lot about a certain person or problem throughout the day, it is possible that it will appear in their dreams that night. Plus, spending a lot of time with a person can make them dream more. Recurring dreams may be caused by anxiety about certain real-life situations that one is not faced with or that have not yet been resolved. Traumatic experiences and memories often appear in dreams and can affect their content. Trauma can also be a factor in recurring dreams. If a critical issue needs to be recognized and faced, the subconscious can work very hard to ensure that this happens. The subconscious mind creates a dream within the dream to keep you from waking up. This creates a safe place to express emotions and resolve problems without interruption..