To Measure Contagion
Epidemiologists study the spread of diseases. They track diagnosed cases over time to look where they occur and how they spread. The disease is identifiable and patients trackable. If I want to measure the spread of loneliness, how can I do it? People do not walk around carrying a sign saying, “I am lonely”.
We need data from the same people over time. That means some kind of longitudinal study. We need a measure of loneliness that is taken at different times. Luckily that is a measure often taken as part of other studies. What is far more difficult is that we need to know the social contacts of everybody in the study over time.
The answer was a pure accident. The Framingham Heart Study started in 1948. It enrolled most of the adult population of this small town in Massachusetts. The team followed up twenty years later. They “captured” the children of the original cohort and their wives. Finally, the third-generation cohort was enrolled. This meant they could track family relations.
The study involved physical heart check-ups every two years. The administrators had to be able to find their participants. Some left the town. Some moved or married and changed their names. Every two years they asked each participant for an exhaustive list of family, friends and work contacts “who might know where you will be in two years’ time”. Those administrative notes were not really part of the study. They were kept and provided the key. From the addresses of people, they were also able to identify neighbors. By combining all this data, they could therefore build a social network. Graphically this looks like this:
Yellow being 0–1 days
Green being 2 days
Blue being 3 days or more.
This picture highlights that lonely people tend to be on the periphery of the network. They have much less contact. We know that loneliness is a psychological state but that it is related to the amount of physical contact.
We can only assess contagion if we have the same diagram at different points in time. We can then track the spread of loneliness through the network. With the Framingham data the researchers were able to do precisely that.
Loneliness is Contagious
Loneliness affects an individual’s network. Someone who feels lonely will have 8% less friends four years later. Lonely people tend to become more reclusive and lonelier. It is a progressive “disease”. As you might expect, the more friends you have the less likely you are to be lonely.
Non-lonely individuals who are around lonely people tend to become lonelier. Someone who is lonely can influence the loneliness of the people with whom they are connected within the network. This extended to three degrees of separation. It is not just that your friend can influence you, but your friends’ friends’ friend. The effect decays with social distance. Like a disease, it can spread through a network.
There is a distance effect. The further away physically the friend is the less likely we are to catch loneliness. There is a big difference between a friend who lives next door and one who lives on the other side of town. Spouses can spread it to each other more easily. If one person in a couple becomes lonely then there is danger for the spouse.
It is not only physical proximity that matters but social as well. Each person was nominating their friends. Obviously, some were reciprocated and others not. Friends’ bonds that went both ways increased the chance of catching the loneliness bug.
Family or Friends for Older People
The researchers looked at the relative impact of different contacts. It is the networks that we have built that matter. Family contact cannot overcome the loss of those friendship networks. Spouses are somewhere in the middle in influence. Age brings a reduction in networks. We tend to focus on a smaller group. Unfortunately, as the group dies, the "remainders" are more vulnerable to loneliness.
Loneliness spreads more easily amongst women than men. This seems to hold whether we are talking about friends or neighbours. This may be that older women are more likely to share their emotions with their friends.
Because of the way it spreads lonely people are linked more often in the network to other lonely people. This is one way that networks protect themselves. An isolated group on the edge of a network can be “discarded”. It could be an implicit fear of contagion. It could be that lonely people are “no fun” and less interesting. Either way the result is that they are dropped from the network. We know that friendship networks are more powerful than family networks. Isolation and rejections by them can therefore be more forceful. We may save the network but the lonely people are in a worse state.
A Global Pandemic
Governments all over the world are worried about loneliness. It is a killer. It affects old and young. We know that it can be genetic. It can come from deprivation. There is however a big social component. If it has the characteristic of an infection disease, then we could be facing a pandemic. As a psychological problem there will be no simple solution. There will be no vaccination but a complex piece of social engineering.