Once there, we begin to ascend back through the four stages again. We repeat this cycle many times throughout the night, with each cycle taking approximately 90-minutes, but gradually increasing in length throughout sleep due to a slight extension to REM during each cycle.
During REM sleep, our bodies are still - somewhat "paralyzed" - deep in the process of manufacturing dreams. In the rapid eye movement stage, our heart rate rises, our breathing becomes more rapid, and our eyes dart around beneath our closed eyelids.(Myers, 2011). REM sleep is the only time in the sleep process in which we dream. .
There are five scientifically debated theories on why we dream. Sigmund Freud believed in what he termed the wish fulfillment theory. According to him, a dream's manifested content is a censored, symbolic version of its latent content, consisting of unconscious drives and wishes. This could also mean that our dreams are revealing a hidden message - what is it that we truly wish could happen? .
The second theory is the information processing theory, claiming that we have dreams to store what we have learned, along with working through the memories we've made throughout that day. This theory claims that people, who would not get enough REM sleep, would do poorly on a learned task. .
The next dream theory is called the physiological function theory. It states that our bodies manufacture dreams to assist us in the development our neural pathways. This theory is very popular with scientists, due to the fact that infants spend most of their time in REM sleep. .
The fourth theory is called the activation-synthesis theory, claiming that REM sleep triggers neural activity that brings random visual memories to our dreams. This is claiming that our dreams are developing stories about us. The last theory is called the cognitive development theory, which claims that dreams reflect our cognitive development (Myers, 2011).
