If you’ve ever said you were craving human contact, you might not have been exaggerating, an MIT study found.
Neuroscientists at the Massachusetts Institute of Technology found the longings people feel during social isolation share a neural basis similar to food cravings when hungry.
“People who are forced to be isolated crave social interactions similarly to the way a hungry person craves food. Our finding fits the intuitive idea that positive social interactions are a basic human need, and acute loneliness is an aversive state that motivates people to repair what is lacking, similar to hunger,” Rebecca Saxe, the senior author of the study, told the MIT News Office.
For its study, the research team collected data in 2018 and 2019, long before the coronavirus pandemic and resulting lockdowns. Their new findings, described today in Nature Neuroscience, are part of a larger research program focusing on how social stress affects people’s behavior and motivation.
To create an isolation environment, the MIT researchers enlisted 40 healthy volunteers, who were mainly college students, and confined them to a windowless room on campus for 10 hours. The participants were not allowed to use their phones, but did have access to a computer they could use to contact the researchers if necessary.
“There were a whole bunch of interventions we used to make sure that it would really feel strange and different and isolated,” Saxe said. “They had to let us know when they were going to the bathroom so we could make sure it was empty. We delivered food to the door and then texted them when it was there so they could go get it. They really were not allowed to see people.”
On a different day, each participant underwent 10 hours of fasting. After the 10-hour period of isolation or fasting, the participants were scanned in an MRI machine while looking at images of food, images of people interacting and neutral images such as flowers.
The researchers focused on the substantia nigra, a tiny structure in the midbrain that has been linked with hunger cravings and drug cravings.
The researchers found that when socially isolated subjects saw photos of people enjoying social interactions, the “craving signal” in their substantia nigra was similar to the signal produced when they saw pictures of food after fasting.
The researchers also found a participant’s normal level of social interaction affected their craving after isolation. “For people who reported that their lives were really full of satisfying social interactions, this intervention had a bigger effect on their brains and on their self-reports,” Saxe said.
Now that the researchers can observe the effects of social isolation on brain activity, Saxe said they can try to answer additional questions, such as how social isolation affect people’s behavior, whether virtual social contacts such as video calls help to alleviate cravings for social interaction and how isolation affects different age groups.
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