While sleep is still a bit of a mystery to science (probably because we’re still largely clueless as to how the brain actually works), we know it’s important. Among other useful effects it’s been shown to help generate neurons, consolidate memories, make rational decisions, keep a healthy immune system—and you need it to function like a regular human being. That said, in our increasingly 24-hour, productivity-oriented world, most of us probably don’t think we get enough.
How great would it be, then, if you could fool your brain that, despite having tossed and turned all night, you were actually well-rested? Psychologists at Colorado University have found that you could actually get “placebo sleep.”
The placebo effect is of course well documented; give someone a sugar pill, tell them it’s aspirin, and their headache will probably feel better. In this new study, published in the Journal of Experimental Psychology, a placebo for sleep wasn’t taken in pill form; it was distributed by simply telling participants they’d slept well.
In an initial experiment, study leaders Christina Draganich and Kristi Erdal asked 50 students to rate how well they’d slept the night before on a scale of one to ten, then randomly assigned them to two groups—“above average” or “below average” sleep quality. The students were given a quick lesson on the importance of sleep, in which they were informed that people who spend less than 20 percent of their sleep time in REM sleep tend to perform worse in cognitive tests, whereas people who spend more than 25 percent of their time in REM perform better.
The researchers then hooked the students up to a device they said could measure their REM sleep from the previous night by looking at their heart rate, pulse, and brainwave activity (such a machine doesn’t actually exist). One random half of the participants were told they had experienced 16.2 percent of REM, and the other were told they got 28.7 percent. Those (fake) results didn’t correlate with how well the students said they thought they slept.
All participants then sat a test called the PASAT, which involves adding numbers together, and which the study authors explained “assesses auditory attention and speed of processing.” The students who were told they got more than the average REM sleep performed to a normal standard, but those who were told they hadn’t slept so well scored below average results.
What’s interesting is that how well the participants originally thought they’d slept—what they reported before being administered a “placebo”—didn’t affect the results. Having a scientist tell them they’d slept badly, just like taking a pill a doctor prescribed, was enough to trick their brains into feeling an effect. In this experiment, however, only a negative placebo seemed to have a real impact on their test scores.
Obviously, what’s more interesting to the actual sleep-deprived among us is whether telling people they slept well could improve cognitive ability. In a second experiment, the researchers added more controls and tested 114 participants’ cognitive skills with three different tests, not just the PASAT. That time, they found that people who were told they had more REM sleep did indeed score better than average on one of the tests (though not all three).
This, they wrote, “revealed that it is possible to provide cognitive enhancement from verbal instruction on sleep quality.”
Draganich and Erdal concluded that the “sleep placebo” effect they observed suggested that “by understanding that one’s mindset nonconsciously contributes to the existence of physiological and cognitive limits, an individual may then be able to consciously extend those limits, experiencing improved cognitive functioning, perhaps without even actually altering sleep patterns.”
Of course, as soon as you know it’s a placebo, you might not get the same effect—outsmarting your own brain is probably quite difficult. In that case, there’s always coffee.