Just one day of forced social isolation evokes a similar neural response as food deprivation, US scientists have found, likening it to a hunger craving.
“It highlights how important being connected with others is for humans,” says Livia Tomova, from the Massachusetts Institute of Technology, lead author of a paper published in Nature Neuroscience.
“I think it is important to pay attention to this social dimension of the current crisis,” she adds, particularly for extreme social distancing experienced by people who live alone or have restricted access to digital technologies such as social media.
It’s well established that loneliness and prolonged social isolation have adverse impacts on physical and mental health, as Tomova and team note in their paper.
To explore the effects of short-term mandatory isolation from a neurological perspective, they recruited 40 healthy, socially connected volunteers aged 18 to 40 to each undergo 10 separate hours of social isolation and fasting, completing questionnaires before and after.
Then participants were shown pictures of their favourite social activities, food or flowers while their brains were scanned with functional magnetic resonance imaging (fMRI), targeting its core motivation reward system in the midbrain, the substantia nigra.
After social isolation, they reported increased social craving, loneliness, discomfort, dislike of isolation and lower happiness and after fasting noted increased food craving, hunger, discomfort and dislike of fasting.
The brain’s “motivation centre” responded in similar ways after isolation and after fasting – after isolation to images of people (not food) and after fasting to images of food (not to social pictures) – and these were correlated with the self-reported longing for social contact or food. The responses were more similar to each other than that evoked by images of flowers.
“If already one day of being alone makes our brains respond as if we had been fasted for the whole day, it suggests that our brains are very sensitive to the experience of being alone,” says Tomova.
Being alone is not always a bad thing, of course, she notes; it can be restorative and life enhancing when purposely sought.
“Previous research has shown that when chosen intentionally, solitude can have positive effects on wellbeing. However, currently people have little choice about whether to isolate or not and while some people might not mind as much, others might suffer from feeling disconnected with others.”