New research published in Memory & Cognition investigated “whether sleep is beneficial for problem solving or whether sleep merely mitigates against interference due to an interruption to solution attempts… Sleep-dependent improvements have been described in terms of spreading activation, which raises the prediction that an effect of sleep should be greater for problems requiring a broader solution search.” Participants completed remote-associate tasks varying in difficulty and repeated these tasks after a period of sleep, wake, or no delay.  The sleep group solved more difficult problems than did the other groups and there was no difference for easy problems. Researchers conclude this suggests sleep is mainly beneficial for solving difficult problems.

Read it in Memory & Cognition.