Poor sleep triggers loneliness, social rejection
Poor sleep can hamper your social life, say scientists who found that sleep-deprived people feel lonelier and less inclined to engage with others, avoiding close contact in much the same way as people with social anxiety.
Researchers at the University of California (UC) Berkeley in the US, have found that alienating vibe makes sleep-deprived individuals more socially unattractive to others.
Moreover, well-rested people feel lonely after just a brief encounter with a sleep-deprived person, potentially triggering a viral contagion of social isolation.
The findings, published in the journal Nature Communications, are the first to show a two-way relationship between sleep loss and becoming socially isolated, shedding new light on a global loneliness epidemic.
Researchers found that brain scans of sleep-deprived people as they viewed video clips of strangers walking toward them showed powerful social repulsion activity in neural networks that are typically activated when humans feel their personal space is being invaded.
Sleep loss also blunted activity in brain regions that normally encourage social engagement.
To gauge the social effects of poor sleep, researchers conducted a series of intricate experiments using such tools as fMRI brain imaging, standardised loneliness measures, videotaped simulations and surveys.
First, researchers tested the social and neural responses of 18 healthy young adults following a normal night's sleep and a sleepless night.
The participants viewed video clips of individuals with neutral expressions walking toward them.
When the person on the video got too close, they pushed a button to stop the video, which recorded how close they allowed the person to get.
As predicted, sleep-deprived participants kept the approaching person at a significantly greater distance away - between 18 and 60 per cent further back - than when they had been well-rested.
Participants also had their brains scanned as they watched the videos of individuals approaching them.
In sleep-deprived brains, researchers found heightened activity in a neural circuit known as the "near space network," which is activated when the brain perceives potential incoming human threats.
In contrast, another circuit of the brain that encourages social interaction, called the "theory of mind" network, was shut down by sleep deprivation, worsening the problem.
For the online section of the study, more than 1,000 observers recruited via Amazon's Mechanical Turk marketplace viewed videotapes of study participants discussing commonplace opinions and activities.
The observers were unaware that the subjects had been deprived of sleep and rated each of them based on how lonely they appeared, and whether they would want to interact socially with them.
Time and again, they rated study participants in the sleep-deprived state as lonelier and less socially desirable.
To test whether sleep-loss-induced alienation is contagious, researchers asked observers to rate their own levels of loneliness after watching videos of study participants. They were surprised to find that otherwise healthy observers felt alienated after viewing just a 60-second clip of a lonely person.
Through a standardised survey researchers found that the amount of sleep a person got from one night to the next accurately predicted how lonely and unsociable they would feel from one day to the next.