The function of dreams is as much a mystery as the function of sleep.
Psychoanalyst Sigmund Freud believed that dreams allow people to express unconscious wishes they find unacceptable in real life. He drew a distinction between the manifest content and the latent content of dreams. The manifest content is the plot of the dream: who’s in the dream, what happens, and so on. The latent content is the dream’s hidden meaning. According to Freud, the manifest content is a symbolic representation of the latent content. In other words, the plot acts as a disguise that masks the real meaning of the dream.
Another theory, called the activation-synthesis theory, proposes that neurons in the brain randomly activate during REM sleep. Dreams arise when the cortex of the brain tries to make meaning out of these random neural impulses. According to activation-synthesis theory, dreams are basically brain sparks.
Some researchers think that dreams express people’s most pressing concerns and might help to solve problems in day-to-day life. If someone has an important job interview coming up, for example, he may rehearse scenarios for the interview in his dreams. If someone has relationship difficulties with a significant other, his dreams may give him clues to help solve the problem.
Some theories argue that dreams arise during the brain’s routine housekeeping functions, such as eliminating or strengthening neural connections. Dreams, then, are a way of cleaning up brain files.
During lucid dreams, people are aware that they are dreaming and may be able to control their actions to some extent within the dream.