According to the Center for Disease Control and Prevention, adults should be getting 7 to 8 hours of sleep each night. We all know that insufficient quality (or quantity) of sleep we get can affect our performance the following day. Sleep deprivation is one of the most common health problems among contemporary adults, with the CDC going so far as to call it an epidemic.
But did you know that even the belief that we didn’t get sufficient sleep can affect our performance as well?
According to the Harvard Business Review, a recent psychological study at Colorado College has proven just that. Colorado College professor Kristi Erdal, along with psychology student Christina Draganich, conducted an experiment in which subjects were tricked into believing that the quality of the previous night’s sleep could be monitored by brain waves.
Slate reports that in this study of 164 students, “Students in the first group were told that their REM sleep the night before had been above average, or 28.7 percent of their total sleep time. Those in the second group were told they had gotten just 16.2 percent REM sleep, well below the average.”
The randomly selected subjects who were told that they had had a below-average percentage of REM sleep the previous night performed markedly worse on a subsequent auditory math test than their counterparts who had been told the opposite. This held true regardless of whether they had actually had a poor sleep cycle the night prior.
Erdal, the professor, told me Draganich’s inspiration for the study was a remarkable 2007 experiment in which Harvard researchers found that telling hotel maids that their job is a great form of exercise actually improved their health. Compared to a group of maids who didn’t get the pep talk, those who were informed about the health benefits of their job were found a month later to have lost weight and improved their blood pressure, according to NPR.