Beautysleep is a real thing, researches have shown that people who have enough sleeplook more attractive (有魅力的) to others.

    A few badnights are enough to make a person look especially "more ugly", theirsleep experiments show.

    Theresearchers asked 25 university students to join in their sleep experiment.They were asked to get a good night's sleep for two nights.

    A weeklater, they were asked to sleep for only four hour every night for two nightsin a row. The researchers took make—up free (素颜) photos of the volunteers afterboth the good and the bad sleep.

    Next, theyasked 122 strangers to have a look at the photos and judge (评价) them on attractiveness, health,and sleepiness, as well as asking them: "How much would you like to makefriends with this person in the picture?"

    Thestrangers were good at judging whether the person they were looking at wastired, and if he was sleepy, his attractiveness score would be low.

    Thestrangers also said they wouldn't want tosocializewith the tiredstudents. The researchers say this is natural for people. An unhealthy-lookingface makes people run away. In other words, people don't want to hang aroundwith people who might be ill.

    Dr Brewer,an expert at the University of Liverpool said: "Judgment of attractivenessis often unconscious (无意识的), but we all do it, and we are able to judge on even somethingsmall like whether someone looks tired or unhealthy. This study is a goodreminder of how important sleep is to us."