since humans wake more quickly from REM than normal sleep, dreams could have evolved to keep us alert for predators in the night. Nightmares may be a specialized form of this; a human makes a sudden, reflexive movement when awoken from a nightmare, which can (by pure chance) collide with a beast that would otherwise have killed him.
― 4356246246@, Thursday, 20 July 2006 06:04 (eighteen years ago)