First, when you were dreaming last night, you started to see things that were not there—you were hallucinating. Second, you believed things that could not possibly be true—you were delusional. Third, you became confused about time, place, and person—you were disoriented. Fourth, you had extreme swings in your emotions—some- thing psychiatrists call being affectively labile. Fifth (and how delightful!), you woke up this morning and forgot most, if not all, of this bizarre dream experience—you were suffering from amnesia. If you were to experience any of these symptoms while awake, you’d be seeking psychological treatment. Yet for reasons that are only now becoming clear, the brain state called rapid eye movement (REM) sleep, and the mental experience that goes along with it, dreaming, are normal biological and psychological processes, and truly essential ones.
Having cast off the non-scientific theory of Sigmund Freud, neuroscience research has since demonstrated that dreaming is not just a byproduct of REM sleep, but serves critical functions for our wellbeing. Can we even take conscious control over our dreams? Scientific evidence suggests the answer is indeed, yes. That fact alone leads to the possibility of self-selecting what experiences (and benefits) we harness from our nocturnal fantasias each and every night?
We often hear stories of people who’ve had remarkable dream-inspired creativity. Think of Paul McCartney’s story of how his hit song, “Yesterday,” came to him in a dream. Keith Richards had a similar dream experience that gifted to him the iconic opening guitar chords of the song, Satisfaction. Or take Mendeleev’s the dream-derived construction of the table of the periodic elements.
It’s been shown that deep non-REM sleep strengthens individual memories. But recent work in my sleep centre, and work of other scientists, has now shown that REM-sleep dreaming is when those memories can be fused and blended together in abstract and highly novel ways. During the dreaming state, your brain will cogitate vast swaths of acquired knowledge and then extract what overarching rules and commonalties, creating a mindset that can help us divine solutions to previously impenetrable problems.
How do we know dreaming and not just sleep is important to this process? In one study, we tested this by waking up participants during the night—during both non-REM sleep and dreaming sleep—and gave them very short tests: solving anagram puzzles, where you try to unscramble letters to form a word [i.e. OSEOG = GOOSE]. We monitored the participants during sleep, woke up them up at different points of the night to perform the test. When woken during non-REM sleep, they were not particularly creative—they could solve very few puzzles. But, when we woke up participants during REM sleep, they were able to solve 15-35 percent more puzzles than when they were awake. Not only that, participants woken while dreaming reported that the solution just “popped” into their heads, as if it were effortless.