Should You “Sleep On It”?
by Christopher Null / October 13, 2012
Yes, if it’s a tough problem…
Previous research has shown that performance on problem solving improves over a period of sleep, as compared with wakefulness. However, these studies have not determined whether sleep is beneficial for problem solving or whether sleep merely mitigates against interference due to an interruption to solution attempts … We conclude that sleep facilitates problem solving, most likely via spreading activation, but this has its primary effect for harder problems.
If none of that makes sense, try reading the research tomorrow.