Beauty sleep is a real thing, according to researchers who have shown that people who miss out on sleep do appear less attractive to others.

美容觉原来是真的：据研究人员表示，错失睡眠的人对其他人来说，魅力显得不足。

A couple of bad nights is enough to make a person look "significantly" more ugly, their sleep experiments suggest.

他们有关睡眠的实验表明，几个睡不好的晚上就足以让一个人的容貌“明显”变差。

Dark-circled "panda" eyes and puffy lids can even put others off socialising with you, they say.

研究人员称，熊猫眼和肿眼皮甚至会使他人与你的交际受到影响。

People were rated by strangers as less healthy and approachable when they had tired faces.

在陌生人眼中，疲惫的面容会被当成不健康、甚至是不便靠近的象征。

The researchers asked 25 university students, some male and some female, to be the guinea pigs in their sleep experiment.

研究人员在他们的睡眠实验中，请来了25名男女大学生来作为实验对象。

They were asked to get a good night's sleep for two consecutive¹ nights. A week later, they were asked to restrict themselves to only four hours sleep per night for two nights in a row.

这些大学生被要求连续两个星期保持优质睡眠。一个星期后，他们被要求在连续两个晚上，每晚只睡四小时。

The researchers took make-up free photos of the volunteers after both the good and the bad sleep sessions.

在这两个优质睡眠和劣质睡眠的环节过后，研究人员给志愿者们照了素颜照片。

Next, they asked 122 strangers - women and men living in Sweden's capital city, Stockholm - to have a look at the photos and rate them on attractiveness, health, sleepiness and trustworthiness, as well as asking them: "How much would you like to socialise with this person in the picture?"

接着，研究人员召集了122名与志愿者素不相识的陌生人。他们当中有男有女，都住在瑞典首都斯德哥尔摩。这些人被要求看着志愿者的照片，对他们的魅力程度、健康状况、睡眠情况和信任程度进行评价。研究人员还会问他们一个问题：“你有多想跟照片上的这个人交朋友？”

The strangers were good at judging if the person they were looking at was tired, and, if they were sleepy, their attractiveness score suffered.

这群人的眼力很好。如果照片上的人显得疲倦不堪，或者看起来很缺觉，他们魅力程度的分数便很低。

The strangers also said they would be less willing to socialise with the tired students, who they also perceived to be less healthy, Royal Society Open Science journal reports.

据英国期刊《皇家协会开放科学》报道，这些陌生人也表示，他们更不愿意与那些看起来很累的学生交朋友，他们认为这些人的身体状况不太好。

The Karolinska Institute researchers says this makes sense in evolutionary² terms.

来自卡罗林斯卡学院的研究人员说，从进化的角度来看，这十分符合常理。

"An unhealthy-looking face, whether due to sleep deprivation³ or otherwise, might activate⁴ disease-avoiding mechanisms⁵ in others."

“一张看起来不健康的脸，不管它是由于睡眠不足还是其他原因导致的，都可能会激活其他人身体内躲避疾病的机制。”

In other words, people don't want to hang around with people who might be ill, whereas someone who looks energetic and fit will hold lots of appeal.

换句话说，人们不想跟可能患病的人待在一起。而那些看起来活力四射、身体健康的人则魅力十足。

Lead researcher Dr Tina Sundelin added: "I don't want to worry people or make them lose sleep over these findings though.

首席研究员蒂娜·孙德琳博士补充道：“我不希望这些实验结果让人们担忧或者睡得不好。”

"Most people can cope just fine if they miss out on a bit of sleep now and again."

“偶尔睡得不好没有关系，大部分人都可以恢复得很好。”

Dr Gayle Brewer⁶, a psychology⁷ expert at the University of Liverpool and member of the British Psychological Association, said: "Judgement of attractiveness is often unconscious, but we all do it, and we are able to pick up on even small cues like whether someone looks tired or unhealthy."

盖利·布鲁尔博士是利物浦大学的一名心理学专家及英国心理学协会成员。他说：“对外表魅力程度的评价往往是无意识的，但是我们一直都在做这件事。我们能够从一些很小的细节，比如说这个人是否疲惫或者是否健康，来对他人进行评价。”

"We want our partners to be attractive and energetic. This study is a good reminder⁸ of how important sleep is to us."

“我们希望我们的同伴看起来魅力十足，充满活力。这个研究对我们来说是一个很好的提醒，它告诉我们，睡眠是多么重要。”