AnAmericanscientistnamedWilliamDementpublishedexperimentsdealingwiththerecordingofeye-movementsduringsleep.Heshowedthatthecommonperson'ssleepisinterruptedfromtimetotimebyspecialeye-movements,somefloatingandslow,othersquickandrapid.Peoplewokenduringtheseperiodsofeye-movementsgenerallyreportedthattheyhadbeendreaming.Whenwokenatothertimestheyreportednodreams.