The article “Big Questions: Why do we dream?” by Carolyn Fay explains the theories of dreams. The study of dreams was revolutionized by two different French scholars by the names of Alfred Maury and Léon d’Hervey de Saint-Denys. Maury worked with an assistant who crafted a mixture of sensory experiences to affect the sleeping body. He might wave perfume under Maury’s nose or tickle his face with feathers. When Maury awoke, he was asked to describe his dreams. The assistant would record the answers as well as gestures and mumbles uttered while Maury was asleep. Their research led them to believe that external stimuli had an effect Maury’s dreams and that all dreams are the result of sensory perceptions. Marquis d’Hervey de Saint-Denys took a different approach by proposing that dreams come from memories. HIs dream lab consisted of a journal, pencil, and mind. He kept a notebook and pencil by his bed and the moment he awoke, he would record his dreams. Later he would sketch them. More details surfaced in his memory and sometimes he would remember and earlier dream by sketching one dream. He concluded that real life reflects scenes into our dreams. Despite a better understanding of the physiology and neurology of the dreaming brain, scientists do not agree on why humans, many mammals, birds and reptiles dream. One theory for dreams is that dreaming connects memories from real life. A 2010 investigation found that participants who learned to navigate a virtual maze performed better on the task after a 90-minute nap than those who didn’t nap. Those who dreamed about navigating the maze did even better — more than six times better than all other participants. Another theory is that dreaming is to help the brain avoid overload from all the information stored during waking hours. The final theory is that humans dream to survive. In 2012 two neuroscientists, proposed a theory of the dreaming mind as a “virtual reality generator” that helps dreamers make predictions about the real world. Some evolutionary psychologists believe that dreaming provided early humans a way to practice life-threatening situations. A 2004 study showed that rats who are deprived of REM-sleep seem to forget many of their natural survival instincts. Dreams may be a nighttime training ground, with nightmares as our best teachers. A dream of running away from a wild animal or of being unprepared for a test could help someone survive a real experience one day.