Researchers exposed a computer brain simulation to different dreams during the three known phases of sleep: wakefulness, non-REM sleep, and REM sleep. They found the three phases appear to have complementary functions for learning: experiencing the stimulus, solidifying the experience, and discovering semantic concepts.
Lead study co-author Jakob Jordan adds, “While non-REM dreams resemble waking experiences quite closely, REM dreams tend to creatively combine these experiences.” Co-author Nicolas Deperrois adds, “We think these findings suggest a simple evolutionary role for dreams, without interpreting their exact meaning. It shouldn’t be surprising that dreams are bizarre: this bizarreness serves a purpose. The next time you’re having crazy dreams, maybe don’t try to find a deeper meaning – your brain may be simply organizing your experiences.” (EurekAlert!)