Research by Dr Simon Williams of the University of Warwick divides sleepers into eight categories, from the socially attentive, intolerant, selfish and anarchic to the snoozers, nappers, feigners and deviants.

• 华威大学威廉斯博士领导的研究，将睡眠者分成8类，从谨守社会规范、不宽容、自私、无法无天，到打盹、小睡、假睡、睡眠不正常的人。