Humans are highly social creatures, and research has shown that feelings of loneliness can have a number of detrimental effects on our health, including a reduction in sleep quality. But as Lacy Schley reports for Discover, a new study suggests that the reverse might also be true: poor sleep leads to loneliness. What’s more, feelings of social withdrawal that are induced by a lack of sleep may be contagious, causing the people around us to feel lonely as well.
The study, published this week in Nature Communications, consisted of a number of different phases. To begin, Eti Ben Simon and Matthew Walker, who are both sleep scientists at the University of California, Berkeley, tested the social and neural responses of 18 young adults after a good night’s sleep and after a night of sleep deprivation. In one session, according to Ed Cara of Gizmodo, the participants were fitted with electrodes and then sent home to sleep normally. During the other session, they spent the night at a lab to make sure they stayed awake.
While both well-rested and sleep-deprived, the subjects participated in two similar tests meant to gauge their sociability. First, an experimenter would walk towards a subject until the subject signalled that the other person had gotten too close for comfort. Then, while undergoing a functional magnetic resonance imaging (fMRI) brain scan, the participants watched videos of a person approaching them; when they felt the person was too close, they pushed a button to stop the video.
The researchers found that when they were sleep deprived, subjects tended to keep the approaching person further away than they did when they were well rested—between 18 and 60 percent further away, in fact. The fMRI scans also showed that sleep deprivation led to changes in areas of the brain that are connected to sociability. When the subjects were operating on less sleep, the videos of the approaching person triggered heightened activity in a neural circuit called the “near space network,” which lights up when we perceive potential threats. Sleep-deprived participants also showed less activity in another brain circuit known as the “theory of mind” network, which is thought to encourage social interaction.
To corroborate their in-lab findings, Ben Simon and Walker asked 138 people to keep sleep logs for two nights, detailing how long it took them to fall asleep and how much shut-eye they got. They found that people who reported poor sleep from one night to the next were also more likely to report feeling increased loneliness the next day. People who slept well, by contrast, reported reduced loneliness.
These results are somewhat intuitive; it probably won’t come as a surprise to learn that exhaustion can make people a little socially withdrawn. More intriguing, perhaps, are the researchers’ findings about the ripple effects of loneliness induced by a bad night’s sleep.
Ben Simon and Walker filmed their subjects answering a series of questions, after both a normal and a sleepless night, and showed the footage to more than 1,000 online volunteers. The volunteers didn’t know that, in some of the clips, the subjects had gone without sleep. They were asked to rate the subjects based on how lonely they seemed, and how likely they were to want to interact with the subjects. The volunteers consistently rated the sleep-deprived participants as looking more lonely and as less “socially desirable,” according to a UC Berkeley statement. And not only that: the volunteers were also asked to rate their own sense of loneliness after watching the clips, and were more likely to report feeling alienated after watching a sleep-deprived person.
“The less sleep you get, the less you want to socially interact,” Walker explains in the statement. “In turn, other people perceive you as more socially repulsive, further increasing the grave social-isolation impact of sleep loss. That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”
The researchers’ findings are not necessarily conclusive; their in-lab study sample was quite small and only included young adults, leaving lingering questions about how sleep deprivation and loneliness might intertwine across a person’s life. But the new study suggests that the relationship between sleep quality and social alienation may be more complex than loneliness causing poor sleep, as previous research has shown.
The new study also suggests that if a person’s sleep disruptions are only temporary, there could be an easy fix to his or her feelings of loneliness.
“On a positive note,” Walker says in the statement, “just one night of good sleep makes you feel more outgoing and socially confident, and furthermore, will attract others to you.”