People are starving for human contact.
As the US approaches nearly one month since the coronavirus pandemic prompted Americans to isolate themselves from family and friends outside the home, many have been chiefly concerned with boredom or newly upended routines. But those who live alone are suffering from an emotion far more insidious: loneliness. For some, the compulsory solitude has already become too overwhelming to bear.
A nationwide study reported this week that 53% of Americans said they had felt lonely or isolated within the past week, particularly those in the 18-to-29 and 30-to-49 age ranges — groups that may be more likely to be single and childless. While mental health plays a considerable role in how individuals cope with being alone, scientists have recently come to reveal that the hungry brain looks strikingly similar to the lonely one.
A prescient new study by researchers at the Massachusetts Institute of Technology being previewed in BioRxiv prior to peer review is the first to show that both loneliness and hunger trigger deep centers of the human brain eliciting feelings of desire and craving. They say their findings suggest that the need for social interaction is as primordial as the need to eat.
Neuroscientists Livia Tomova, Rebecca Saxe and their team say they had no idea how timely their research, which began more than three years ago, would be today — as COVID-19 forces people around the world to seek shelter and socially distance themselves for the near future. In fact, they hardly could imagine a world outside of prisons where the scenarios they tested would be played out in reality.
“I sometimes struggled to articulate what that would be like in the real world,” Saxe told Scientific American. “Why would that ever happen?”
By the time Saxe and her colleagues were writing the study, their worst-case scenario had become the new normal.
“What feels most significant about this paper is that it’s a way to step outside the experience we’re having and look on it through a different lens,” Saxe said.
Using functional magnetic resonance imaging (fMRI), scientists compared brain responses in 40 healthy adult volunteers after 10-hour deprivation periods forcing either loneliness or hunger. The rules on food-deprivation day were simple: No eating or drinking anything but water.
Evoking loneliness was less straightforward, as some people crave regular social interaction, while others are more comfortable with solitude. To create the most consistent feeling of loneliness, participants were confined to a stark room at a lab with no phones, computers or novels, as some might have been inclined to bond with the characters. From 9 a.m. to 7 p.m., they were allowed only puzzles and pre-approved nonfiction reading or writing.
Immediately following the sessions, the volunteers were subjected to brain scans, focusing on a midbrain region called the substantia nigra, as well as visual cues, such as images of food or hugging, meant to induce craving. An active substantia nigra indicates a strong wanting that is produced by a dopamine release.
“We found that this brain area specifically responded to the cues after deprivation but only to cues of what they had been deprived of,” said Tomova — meaning that periods of solitude were not soothed by pictures of participants’ favorite snacks. The brain’s response correlated with the subjects’ self-reports of how lonely or hungry they felt, though their reported feelings of hunger were consistently stronger than feelings of loneliness.
The scientists put their results through AI analysis to trace neural patterns between the two brain states, which told them “that there seems to be an underlying shared neural signature between the two states,” Tomova said. “Social contact is a very basic need.”
Tomova and Saxe hope to continue their study, particularly to reveal how social media impacts loneliness — for better or worse.