Putting off an important decision until you’ve had a chance to think it through (instead of relying on impulse) has always been a good idea. “Let me sleep on it and get back to you tomorrow” sums this up nicely.
Now, it turns out, there is evidence that it’s not just the time for reflection and consideration that’s important in this process, but the sleep itself.
Researchers at Harvard Medical School and McLean Hospital recently found that people who were sleep deprived performed less well on a standardized test simulating real-life decision making known as the Iowa Gambling Test than they had at baseline when they were well rested. Even when given stimulants such as caffeine or amphetamines, the ability of the participants to make good decisions only returned to baseline after they had recovery sleep.