Glamour: How to interpret dreams, according to scientists—and why we remember some but not others.

“Dreams represent sleep mentation”—aka imagery and thinking during sleep—”and there are many dimensions to that,” says David Neubauer, M.D., associate professor of psychiatry and behavioral sciences at John Hopkins Bayview Medical Center. In other words, dreams are a series of fragmented visions and thoughts that come to us while we’re unconscious. 

Dreams occur mostly during REM sleep, also known as paradoxical sleep—a sleep stage in which “your brain is moderately active and thinking about things and processing information,” says Philip Gehrman, Ph.D., associate professor of clinical psychology in psychiatry at the Hospital of the University of Pennsylvania.