Somewhere between two and seven percent of adults insist they don’t dream. But, are their sleeping minds really inert or do these self-acclaimed non-dreamers merely not remember the stories that swirl around in their heads during REM sleep?
Researchers from the Sleep Disorders Unit at Pitie-Salpetriere University Hospital in Paris think that a sleep disorder might hold the key to figuring out if an inability to recall dreams signifies a failure to have them.
Something is different about the brains of people who remember their dreams and those who rarely or never do. A 2014 study, for one, showed reduced regional activity in the brains of infrequent dream-recallers. And, back in 2003, a big-deal study challenged the notion of dreaming as a universal experience.
In the experiment, researchers woke up non-recallers as well as sometimes-recallers at the end of their REM cycles when dreams would be the freshest in their conscious minds. Non-recallers still said they remembered nothing, whereas sometimes-dreamers with the same clinical, demographic and behavioral profile reported minimal recollection. Spontaneous, REM-awakening typically provokes greater and more intense recollection than does natural awakening that occurs later during rest. The research was compelling, but researchers still didn't have direct access to dream activity.
The Parisian team realized that monitoring patients with REM Behavior Disorder (RBD) might give them the entry point they needed.
Thanks to a neurological glitch in the brain system that ordinarily shuts down limb movement during REM sleep, people with RBD act out their dreams. In the throes of unconscious adventures, they’ll thrash, curse, laugh and even draw non-existent cigarettes to pursed lips. The tone of observed behavior tends to match the dramatic dreamers’ description of their dreams. But, not everyone with RBD can provide a rundown of their nighttime antics, as a slim portion of them say they don’t dream, despite evidence to the contrary.
So, researchers thought to compare sleep behavior of dream-recallers and non-recallers who’d been diagnosed with RBD. In the study, published in the Journal of Sleep Research, dreaming was defined as “the waking report of any awareness of feelings, thoughts or emotions that had occurred during sleep,” including “white dreams,” which refers to the feeling that dreaming happened without the ability to remember the experience.
Of 289 RBD patients included in the study, 2.7 percent said they hadn’t recalled dreams for at least 10 years. Another one percent, the “true” non-recallers, said they’d never dreamed.Their behavior, however, suggested otherwise: Every RBD patient acted out their dreams — babbling and swearing and gesticulating wildly — whether or not they had any memory of the experience.
That the simple act of observing people flailing in their sleep could resolve something as seemingly irresolvable as gaining knowledge of someone else's mind is rather difficult to believe. Regardless, there's more to find out. "It would be fascinating," study authors wrote, "to provide cues to the never-recallers following awakening from RBD behaviors to determine wther they allow some dreams retrieval."
As neural exploration continuously shows, brain activity is sneaky. Last year, researchers discovered what they interpreted as evidence of conscious thought in people in persistent vegetative states (brain dead). Who knows what we'll discover about dream activity in those who say they don't dream. But chances are there'll be a whole lot of action.