Precisely at the outbreak of the coronavirus pandemic, you had the results of a study that explored how social isolation becomes manifest in the human brain. What were your findings?
Livia Tomova: We looked at one specific brain region – the substantia nigra – which constitutes the core of our motivational system in the brain. We found that this brain region showed similar responses after fasting and after isolation. When people were isolated, this brain region showed higher activity in response to images of other people (rather than images of food). Conversely, when people were fasting and were then shown pictures of food, the substantia nigra showed higher activity in response to these pictures (than to social pictures).
The level of activity we found in the substantia nigra was consistent with how much the subjects indicated they craved food or social contact. In a next step, we used machine learning and taught a computer algorithm what neural signals from a hungry person looking at pictures of food look like to enable it to identify them. We then “showed” this algorithm brain signals from a lonely person looking at pictures of other people and asked if it could distinguish these from control signals without having “seen” these brain signals before. And indeed it could! This suggests that there is a common neuronal signature between the craving for food and the craving for social contact.
Were you surprised by the result?
Tomova: The results corresponded to our hypotheses. Some colleagues had previously suggested that loneliness may be a signal to get us to do something about the lack of social contact – this theory was put forward especially by the group of researchers around the psychologist John Cacioppo, the co-founder of the field of social neuroscience at the University of Chicago. Thus, loneliness can be interpreted in a similar way to hunger. It is an emotion designed to drive us to do something about a lack of something. Our data now provide empirical support for this hypothesis.
For the last year, we have now been finding ourselves in a kind of real-life laboratory. How exactly does isolation affect mental and physical health?
Tomova: In our study, we found that even as little as ten hours of isolation caused the test subjects to experience more negative emotions. This tallies with studies on loneliness, which demonstrate that lonely people more frequently suffer from depression and other mental health problems. I think our results show very clearly that people react very sensitively to a deficit in social interaction.
Can the hunger for encounter, touch and personal exchanges be compensated for by social media or by anything else?
Tomova: That’s a good question, but unfortunately we don't have an answer at this point. My research puts a central focus on this aspect, however, and I would like to dig deeper in the course of forthcoming studies. Currently, we have very limited knowledge about how social media affect our social life. Findings presented so far suggest that social media have partly positive effects on exchanges with others – if we use them pro-actively, i.e. if we actively talk to people and engage with them. Passive consumption of social media, i.e. only looking at content such as photos or other people's posts, tends to have more of a negative effect on our well-being.
Is it possible to get used to loneliness?
Tomova: Previous studies tend to indicate the opposite. People who suffer from chronic loneliness also have more health problems. These problems affect mental health but also physical health, since loneliness is a state of stress. However, it is important to distinguish between loneliness and being intentionally alone. The English language has two different terms for this: “loneliness” and “solitude”. The latter describes a state of being alone that does not necessarily have to be negative; quite the opposite: it can also have positive effects. Many people find it very wholesome to spend time alone, which is not what we call loneliness. Loneliness, on the other hand, can be understood as a subjective state in which our level of social interaction is lower than we would like it to be – which means it is negative by definition, since we subjectively feel a deficit.
You are currently exploring how isolation affects young people. Can you confirm that social distancing is particularly hard on the young generations – and if so, why?
Tomova: It is a defining characteristic of young people that they want to spend time particularly with their peers. This is a fact that can be observed across cultures - and even across species! Brain research studies have shown that this behaviour is important because adolescent brains are still developing. This process particularly affects brain regions responsible for higher and social cognition.
Recent studies have shown, by the way, that this development is only completed around the age of 25. This means that many young adults are still going through important stages in brain development. Last year, together with colleagues of mine I published a commentary on this topic in the Lancet journal. We argued that social distancing actually has negative effects, especially on adolescents. For, in order to be able to go through these important developmental stages, it is essential for the young generation to have active interaction with peers.
Livia Tomova completed her doctorate in psychology at the University of Vienna in 2016. This was followed by several years of postdoctoral training in cognitive neuroscience at the Massachusetts Institute of Technology (MIT), funded in part by a Schrödinger Fellowship of the Austrian Science Fund FWF. She investigated how the human brain is affected by not having its social needs met. Her research was published in Nature Neuroscience in November 2020. In the same year, Tomova was awarded a Henslow Research Fellowship at the University of Cambridge, where she is studying the effects of loneliness on adolescents and whether and in what manner new media can meet social needs.
Effects of social isolation – biological alarm bells?
Loneliness is very stressful, both mentally and physically, and it increases the likelihood of earlier death. But the stressful feeling of being lonely may serve a purpose. Psychologists suspect that loneliness is painful in order to serve as a biological alarm bell. New findings confirm this theory.
About four years ago, when the psychologists Livia Tomova and Rebecca Saxe of the Massachusetts Institute of Technology and their colleagues started their work, they wanted to show how loneliness works in the brain. Their results became available precisely at the time when the coronavirus pandemic was spreading worldwide in March 2020. Similar research had previously been conducted on animals, but this was the first human study to show that loneliness is signalled in a similar way to hunger. Both loneliness and hunger share signals in a region seated deep in the brain that controls basic impulses for reward and motivation. The research suggests that our need to engage with others is as fundamental as our need to eat.