It is a mystery that has fascinated humanity and puzzled scientists for centuries. And, without reliable or objective ways to understand the content of people’s dreams, we’re left in the dark for the most part. However, studying particular stages of sleep might now hold the answers to dreams’ purpose. Watch this video or read the transcript from Inside Science to explore the theory.
Why do we dream? Sigmund Freud said dreams are the hallucinatory fulfillment of an oppressed infantile wish. Well, that was 100 years ago – how do we think about dreams now? We can describe dreams as vivid, sensorimotor hallucinatory experiences. Now, think back through your own dreams. They share common features. They have a narrative. They generally involve other people. And those people are often hostile. Dreams are always shaped by our own individual experiences and memories. But how can we actually learn about them?
First, you need to find someone who is dreaming. But, you can’t just ask a sleeping person to tell you whether they’re dreaming or not, without stopping them from dreaming. But you can do something almost as good. There is a stage in the sleep cycle called rapid eye movement sleep, or REM sleep. During REM sleep, nine out of 10 people report dreaming. So, researchers often use REM sleep as a signal that someone is dreaming. Those flickering eye movements have even been suggested to correspond to scene changes during dreams.