Some of us have wild and weird dreams nightly, while other people swear they never dream. But is their sleep truly dreamless — or could it be that they never remember their dreams? A team of French researchers set out to investigate this question, and their results are published in the Journal of Sleep Research and summarized earlier this week over at the Discover blog Neuroskeptic.
The researchers specifically studied this in people with REM sleep behavior disorder — the thing comedian Mike Birbiglia has and based an entire semiautobiographical movie on. People with this condition act out their dreams as they’re sleeping (say, by jumping out the window of a La Quinta in Walla Walla, Washington, as Birbiglia famously did). And so by studying people with this disorder, the sleep scientists thought they could get a good idea of who was dreaming, and who was not, by observing their movements as they slept. Before they did that, though, they gave the 289 participants a questionnaire, asking them whether they dreamed.
A small portion of the study volunteers — just under 4 percent — said they either never dreamed or hadn’t in more than a decade. And yet the way they moved in their sleep seemed to indicate otherwise. One participant, for example, was a man in his 70s who said he stopped dreaming in his 20s. But the video the scientists recorded of his sleepover in the lab shows him "arguing, swearing profanities, kicking, boxing and throwing items towards an invisible individual" in his sleep. While this was going on, he was talking, too (translated from French): "What can I make to eat, I saw … You listen … (incomprehensible words, then high-pitched voice). Stay here before doing such a thing, you b*tch!"
His behavior suggests he is dreaming, but that his dreams vanish upon waking. Although it also could be true, as the Discover writer points out, that this man and the other non-dreamers in this study may have been behaving as if they were dreaming but weren’t actually experiencing the corresponding images. Really, who’s to say what’s going on inside someone else’s head?