Are You Getting Enough “Placebo Sleep”?

The Atlantic writes up a Colorado College study that suggests we’d be less sleepy if someone were to fool us into thinking we’d gotten more sleep:

Participating undergrads first reported how deeply they’d slept the night before, on a scale of one to 10. The researchers then gave the participants a quick, five-minute lesson about sleep’s effect on cognitive function, telling them it was just background information for the study. During the lesson, they said that adults normally spend between 20 and 25 percent of their sleep time in REM sleep, and that getting less REM sleep than that tends to cause lower performance on learning tests. They also said that those who spend more than 25 percent of their sleep time in REM sleep usually perform better on such tests.

Then participants were hooked up to equipment that they were told would read their pulse, heartrate, and brainwave frequency, though it actually just measured their brainwave frequency. They were told that these measurements would allow the researchers to tell how much REM sleep they’d gotten the night before. This was not true.

Sick research burn. Then, each undergrad was told they’d either gotten 16.2% REM sleep or 28.7% REM sleep; their subsequent performance on a cognitive test reflected the quality of sleep they were told they’d gotten, rather than the quality of sleep they’d reported before. In conclusion, you are deeply rested; you slept so well last night.