If the person looked exhausted, they were marked less on attractiveness.
Using 25 University students, some female and some male, Swedish researchers found that when participants appeared visibly exhausted they were less likely to be approached by strangers or friends.
Their night-time movements were tracked so they couldn't cheat, naturally. One week later, subjects were asked to restrict their sleep to just 4 hours on 2 consecutive nights. They also asked them, 'How much would you like to socialise with this person in the picture?' As it turns out, not getting enough sleep made participants score worse on all counts.
Two consecutive nights of restricted sleep could be enough to make someone appear less attractive to others, as well as making people less interested in hanging out with them, according to a joint study from New York University and the Karolinska Institutet in Sweden. Recent findings show that acute sleep deprivation and looking exhausted are related to decreased attractiveness and health, as perceived by others.
"Recent findings show that acute sleep deprivation and looking exhausted are related to decreased attractiveness and health, as perceived by others", they add.
According to the study, this makes sense from an evolutionary perspective.
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The volunteers were perceived to be less healthy-looking, less sociable and less intelligent after half the amount of sleep.
Next, the researchers recruited 122 adults - referred to as "raters" - and asked them view each photograph.
The study was well-received in the community.
Psychology expert at the University of Liverpool and member of the British Psychological Association, Dr Gayle Brewer, 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 exhausted or unhealthy". Because we've evolved to try to avoid diseases, seeing an unhealthy-looking face makes us want to avoid that person.
But sometimes we forget just how important sleep truly is, and need a little nudge from a different direction.
Journal Reference: Tina Sundelin, Mats Lekander, Kimmo Sorjonen, John Axelsson - Negative effects of restricted sleep on facial appearance and social appeal.