Not getting enough or the right kind of sleep is notoriously bad for physical health. But a new study out of the University of California, Berkeley suggests that poor sleep can be a nightmare for our social lives too. It just might turn us into lonely outcasts, capable of spreading our misery to others.
We already know that poor sleep quality is linked to negative experiences like anxiety, depression, and loneliness. Many of the studies exploring this connection have suggested loneliness worsens our sleeping habits. But there’s been less research on whether the opposite is true. So the scientists behind this latest study decided to perform a series of experiments, using both offline and online human volunteers, to find out.
First, they recruited 18 healthy university students who were screened for any sleeping problems. The volunteers were asked to come by the sleep lab for two sessions, the order of which was randomised. In one session, they arrived at the lab and had electrodes attached to measure their sleep activity, then were sent home to sleep as normally as they could. In the other session, they instead stayed the night at the lab, and were monitored to make sure they didn’t sleep at all.
In either session, the next morning at the lab, volunteers filled out surveys about their mood and and anxiety. They also completed two similar types of tasks, meant to measure their preferred level of social interaction. Afterwards, the volunteers were interviewed on film about current events for about 20 minutes.
In one task, the volunteer and experimenter stood three feet apart, facing each other. The experimenter then walked toward the volunteer until they were close enough to make the volunteer feel uncomfortable; the task was then reversed, with the volunteer walking towards the experimenter. Both scenarios were then repeated with an experimenter of the opposite gender. In the second task, the routine was repeated, but virtually. While the volunteers had their brains scanned via functional magnetic resonance imaging, they watched videos of both computerised people and objects steadily approaching them. They were asked to signal when exactly they felt unnerved by the ever-nearing avatar.
Across both the real and virtual tasks, the researchers found, people’s desire for personal space increased when they hadn’t gotten any sleep the night before. They also reported feeling lonelier than they did after a full night’s sleep.
Not content to stop there, the authors then turned to the internet. They recruited online volunteers in the US through Amazon’s Mechanical Turk. Over the course of two nights, people were asked to keep track of their sleeping patterns, as well as their anxiety and mood. As before, people who reported poorer quality sleep on at least one of those two nights felt lonelier, on average, than people who slept soundly both nights.
Finally, the researchers used online volunteers to watch short clips of the interviews that took place during the live test (the same person was never seen twice). Without knowing anything else about them, including how they slept the night before, the online volunteers were asked to rate the interviewees on characteristics like loneliness and social desirability, as well as how active they looked.
Even from afar, the sleep-deprived volunteers were more often seen as anti-social. And interestingly enough, when the online volunteers were asked about their own moods after watching these clips, they reported feeling worse about themselves after seeing clips of people who felt lonely.
The chain of events the authors stumbled upon might be enough to send sleep-deprived people spiralling down further into social ostracisation.
“The less sleep you get, the less you want to socially interact. In turn, other people perceive you as more socially repulsive, further increasing the grave social-isolation impact of sleep loss,”said senior author Matthew Walker, a UC Berkeley professor of psychology and neuroscience, in a statement. “That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”
Sleep deprivation itself seems to be at least partly responsible for people’s increased isolation, rather than its effects on our general mood, the study’s findings indicate. There was no connection between people’s anxiety or negative mood and their reported loneliness after their sleeplessness. For instance, someone who felt more isolated after getting no sleep wasn’t necessarily more anxious than they were during the session they had with a full night’s sleep.
It might be fairly obvious to anyone who’s had to pull an all-nighter that not getting enough sleep can make us cranky and less willing to talk to anyone. But the volunteers’ brain scans also suggest there are more subtle changes going on: When the volunteers were sleep deprived, their brains showed higher neural activity in a region known to help us evaluate possible threats, while also showing lower activity in a region that helps us read other people’s intentions.
Of course, the paper, published today in Nature Communications, is just one study. And despite the attempts to verify their results in other ways, the sample size of the first experiment alone should make us guarded about accepting its findings at face value. But if the sleep-loneliness connection is real, the authors say it could have some major implications.
For one, it’s known that as we age, we tend to become lonelier and have trouble sleeping. We also know other groups, such as teenagers, are sleeping less than previous generations did, thanks in part to the wide availability of smart phones and screens, while the rate of mental health issues like depression among the young has increased in recent years. If sleep loss is both a potential cause and effect of loneliness and other mental health issues (which some recent studies have suggested), then it becomes that much more urgent to find public health interventions to help us slumber peacefully. [Nature Communications]