After analyzing the results, the scientists found the sleep-deprived group wanted greater distance compared to the rested group. When the scientists evaluated the brain images, which were captured during the video experiment, they saw heightened activity in a neural circuit known as the "near space network," which is activated when a person feels threatened.
"It's perhaps no coincidence that the past few decades have seen a marked increase in loneliness and an equally dramatic decrease in sleep duration," lead author Eti Ben Simon said in a statement. "Without sufficient sleep we become a social turnoff, and loneliness soon kicks in."
For the second part of the trial, more than 1,000 observers viewed videotapes of study participants discussing day-to-day activities. The spectators, who did not know the subjects were sleep-deprived, rated them as “lonelier and less socially desirable,” the authors wrote.
“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,” senior author Matthew Walker said. “That vicious cycle may be a significant contributing factor to the public health crisis that is loneliness.”
Furthermore, the researchers administered a survey to test whether "sleep-loss-induced alienation" is contagious. They found that healthy observers felt alienated after viewing just a 60-second clip of a lonely person.
“This all bodes well if you sleep the necessary seven to nine hours a night, but not so well if you continue to shortchange your sleep,” Walker said. “On a positive note, just one night of good sleep makes you feel more outgoing and socially confident, and furthermore, will attract others to you.”