“Sleep on it” is common advice when you’re facing a tough decision, and now researchers have discovered scientific evidence that sleeping really can help people come up with solutions to problems.
In a study done at the University of California at San Diego, scientists asked participants to solve test questions before and after taking a nap.
People who took a nap that included a phase of rapid eye movement (REM) sleep performed 40% better on the test than participants that napped without REM or didn’t sleep at all.