In his book, Friends, evolutionary psychologist Robin Dunbar distils the results of years of research into how human beings form and maintain friendships. There is a lot in this research that could be usefully learned from and applied in our churches. Here are my main take-homes.

Friendship is not an optional extra
Friendship is not only nice to have but is essential to our health, making a measurably large impact on life expectancy. Dunbar claims the research shows that friendship is more significant for our health than what we eat or whether or not we exercise. Only stopping smoking will make a bigger impact on health outcomes.

The impacts of friendship start young. The more socially integrated we are when young, the more healthy we will be when older.

Christianity is a faith that – remarkably – calls us into friendship with God (John 15:15). It is not surprising, then, that church is a place where people make friends. This has been made more challenging through lockdown, and has been especially challenging for children and young people. We need to be intentional about creating opportunities for people to connect and make friendships – it’s essential for our physical as well as spiritual health.

Friendship is limited
Dunbar is best known for the ‘Dunbar Number’. This is the observation that human societies consistently organise themselves into groups of 150, this being the maximum number of people we are able to relate to as friends.

There is a scaling of ‘threes’ in this: typically, we have five close friends; fifteen best friends; fifty good friends; 150 just friends; 500 acquaintances; and 1,500 people we know by name.

This is fascinating sociologically, but also has considerable relevance to church life. It is why in church leadership teams there is often a core group of three to five people and why relationship dynamics get complicated – and messy – if the leadership team exceeds fifteen. It is why most congregations number 150 or fewer. It’s why small groups function best when there are around fifteen members. It’s why larger churches have to structure things so that people operate within groups of five, fifteen, fifty or 150.

These limits on friendship do seem universal. It is unwise to ignore them.

Friendship is sexed
Dunbar offers observations, not moral positions, but he steps into territory that is controversial in our current cultural context; one of which is that there does seem to be a significant difference in how the sexes approach friendship. At the most stereotypical level, girls’ friendships are dependent on talking; the friendships of boys on doing. This is why, “men seem to enjoy, and work more effectively, in clubs”, in a way which isn’t the case for women.

This difference in approach to friendship means the sexes naturally segregate. Dunbar states the research reveals that, “Around 70 per cent of women’s personal social networks consist of women, and around 70 per cent of men’s social networks consist of men (with most, but not all, of the cross-gender members being family members over whom we have little choice).”

This insight might reassure us that it is not necessarily wrong for a church to run activities segregated by sex. Doing so could actually be beneficial to the whole church as it provides space for both men and women to make friends in the way men and women prefer to do. It also means we shouldn’t worry too much if looking around at church events we notice the men in one corner and the women in another – that’s just what tends to happen.

Friendship gets our endorphins going
There are certain things humans do together that raise our endorphin levels and are particularly effective in creating a sense of togetherness and belonging.

One of these is music. When a group of people – even if they are strangers to one another – make music together a strong sense of oneness is created. Moreover, singing in large groups has a more powerful bonding effect than singing in small groups. Laughter also has this effect, as does eating and drinking together.

Research on the effectiveness of the Big Lunch initiative showed that, “Four things emerged as common factors predicting how satisfied they were with the occasion: the number of diners (more is better), the occurrence of laughter, reminiscing about the past, and the consumption of alcohol. The occurrence of laughter and reminiscing both resulted in an elevated sense of bonding to the other people than was the case where neither happened.”

The relevance of this to church life is obvious. Church is a place where we sing, and singing is powerful. We need to get back to singing! Church should also be a place where we laugh. I’m grateful it is a rare Sunday when there would not be real laughter in my church. Churches are communities where we should be regularly eating and drinking together, another thing we’ve missed through lockdown.

All this comes into particular focus in the celebration of the Lord’s Supper: eating, drinking, singing, remembering. And yes, at times laughing, as we proclaim the Lord’s death and anticipate his coming. How denuded our experience of the Supper has so often become: it’s meant to be a celebration, that draws us together as friends to our greatest friend.

Friendship builds on story
Reminiscing is a key part of building friendship and the evidence is clear that we remember stories much more than factual accounts. Dunbar explains that this is because in order to navigate our way through the incredible cognitive demands of the social world understanding why someone acted as they did is more useful to us than knowing what they did. Understanding the why helps us navigate life – which is why we love stories.

Every preacher knows this: people remember the illustration more than the factual content of a sermon. At times this can feel very frustrating, but it shouldn’t be. We just need to get better at telling stories that help people to grasp and remember what it is we are trying to teach them.

Friendship has a limited attention span
Something I have often observed is that a group of us can be sitting in a team meeting, having a conversation, when suddenly there are two conversations going on in the room. This can be annoying – ‘Hey guys – don’t you want to hear what X here is saying?!’ – but Dunbar explains why this always happens.

Conversation is very cognitively demanding and we are simply not capable of holding an extended conversation in a group larger than four. A group larger than four listening to someone speak is a lecture, not a conversation. Conversations don’t last with more than four people – a fifth person joins and within seconds two conversations will form. And there is selective sorting by sex here too: when there are more than four in a group, and both men and women in the room, conversations very quickly split by sex.

This observation has all kinds of practical applications in church life: how we organise discussion groups, team meetings, discipleship structures, and so on.

Friendship is discriminatory
This is another area where the research points in directions we might find uncomfortable: the reality is that we tend to gravitate towards people who are like us – who think similarly. There even seems to be a biological and not only psychological basis to this. Dunbar includes the startling evidence that, “You are twice as likely to share genes with a friend as you are with any random person from your local neighbourhood.”

Our preference to choose our friends by ‘type’ is unambiguous. “Not only do we like people who think more like us, we also tend to prefer people of the same sex, ethnicity, age and perhaps even personality.” Does that mean we are all racist? Dunbar thinks not:

A preference for ethnic origins does not of itself necessarily imply racism, in the sense that we currently understand this term (i.e. differentiation based on skin colour). What you seem to be looking for is someone with the same cultural background because that makes it possible to create friendships and community bonding.

This presents issues for the church. We talk a lot now about racial differences but I’ve always thought that culture – or in British terms, social class – often presents a greater challenge. You might worship in a church which displays many different skin tones, but if everyone is university educated and in the socio-economic ABC1 demographic it is questionable if you really have a diverse church.

So this is a missional and ecclesiological issue: how do we best accommodate the reality that most people prefer to be with people like themselves and equip the saints to reach those who are culturally different? In Christ, that should be possible, but it certainly isn’t always easy.

Friendship is harder with age
As we get older it becomes increasingly demanding to make and keep friends. People move away, and then start dying, and we are more set in our ways. The old are less ‘attractive’ because they seemingly have less to offer by way of friendship. Thus we see the reality of many old people living very lonely lives.

There is a real opportunity for the church here, if, as Dunbar says, “The provision of social clubs and activities for the elderly [are] all the more important as a way of maintaining their mental and physical health.” Most of those clubs and activities got shut down during the pandemic – they need to start again.

Friendship needs to be face to face
Dunbar closes his book with an examination of the impact of the internet on friendship. There is a lot that we still don’t know about this impact – only time will tell. But we do know that close friendships require frequent face-to-face contact. Phone calls and email are great but they can’t take the place of actually being together. Zoom is better but works poorly for larger groups. If we are unable to maintain a conversation in groups of more than four people when we’re physically present there is no way we can manage it on Zoom. This is why so many of us have experienced ‘Zoom fatigue’ throughout the pandemic – being on screen with more than three other people is exhausting.

Friendship needs to be face to face. ‘Online church’ has a very limited shelf-life: it can plug some gaps and do some good but it simply cannot replace direct human interaction.

The pandemic has presented us with many challenges. I’ve been grateful for good friends who have stood by me, encouraged me, rebuked me, helped me and laughed with/at me over these months. But friendship has also been stretched. There are friends I have not seen for a long time, meals I haven’t had, conversations postponed. Friendship is precious – we need friends! Do yourself a favour, go and see a friend.