Sleep stages and problem-solving.

Subjects who achieved slow-wave sleep (SWS); Subjects who did not achieve slow-wave sleep (No SWS); Subjects who achieved rapid eye movement sleep (REM); Subjects who did not achieve rapid eye sleep (No REM); Subjects who remembered their dreams (Dream Recall); Subject who did not remember their dreams (No Dream Recall). Statistical comparisons are presented as the following, SWS vs. No SWS, REM vs. No REM, Dream Recall vs. No Dream Recall.