I’ve done a lot of reading, thinking, and ‘trying out’ when it comes to belonging in organisations and teams, always attempting to think sceptically and critically so that I follow evidence and never hitch my wagon to ‘nice to haves’, but rather get to grips of the whys and hows of groups working well. The Social Brain delves into exactly this, exploring how our natural social behaviours can be leveraged to build more effective and more satisfying workplaces.
In Summary
The Social Brain asks how we can better utilise innate human social behaviour to create organisations that succeed by traditional metrics, while also fostering more fulfilling social environments for employees. The authors explore group size (using Dunbar’s Number), belonging, bonding, organisational communication, and other factors to help us understand how groups form and thrive.
As you’d expect, there is a wonderful balance of research, reflections, and practical application along the way.
My Key Takeaways
- Dunbar Number: I’ve read various research about optimal group size, but the Dunbar Number / graph is super interesting. Dunbar argues that stable group sizes come in set sizes, namely: 5, 15, 50, and 150, with the latter being a good upper limit for most communities to still be ‘friendly’ or familiar with each other. It’s a reminder that simply adding people to a team without considering these natural limitations will inevitably lead to inefficiencies and communication breakdowns. For more of an explanation on the Dunbar number, check this out. https://www.newscientist.com/definition/dunbars-number/
- The importance of these numbers: Large teams suffer from several unavoidable structural disadvantages. One is simply that the number of communication exchanges that have to take place to ensure everyone is up to speed increases exponentially with the size of the team. With a team of four, there are six pairwise connections (e.g. persons a&b, a&c, a&d, b&c, b&d, c&d); with a team of ten, there are forty five, a proportional increase of 300 percent. As you can see, group size doesn’t have to increase by much for this to cause a problem. The result is an inevitable increase in inefficiency, possibly because there is more opportunity for ‘social loafing’ or coasting. Analysis in different teams from the automotive industry found that the average team size was 9.4, but that staff estimated this to be too big by 1 person; in another study of software teams, 4.4 was the optimal number for the most successful teams. Do we consider our group sizes? For larger school teams, do we consider how we can utilise good communication and groups within our teams for projects, to enhance efficiency and minimise social loafing?
- Belonging: this area of the book resonated with me, having spent a lot of time researching belonging and community. The authors discuss the idea of ‘fictive kinship’, whereby organisations create (but not necessarily try to emulate!) a sense of family and togetherness. This means paying attention to rituals of welcome and creating shared experiences that foster genuine connection, not just transactional relationships within rigid hierarchies. Ultimately, we spend a lot of time at work, and investing in belonging and connection not only improves outcomes, but makes us feel part of a community where we are valued and cared for.
- Homophily – describes the human tendency to associate with and befriend those similar to ourselves – it’s a fact, we just do! It manifests in two forms: Endogenous homophily, based on unchangeable aspects of our makeup, such as gender (e.g., 70% of personal social networks are the same gender) and age. However, Exogenous homophily refers to acquired or learned traits, like common language, shared upbringing location, or educational/career experiences. The presence of homophily inevitably leads to silos in organisations, as like-minded people gravitate together. Organisations can address exogenous homophily by fostering an engaging culture where we celebrate similarities and differences, and create conditions for groups of any makeup to collaborate and achieve things together.
- Seven Pillars of Friendship: of the exogenous factors, the seven biggest indicators of whether two people will form a meaningful friendship are known as the seven pillars of friendship – the more of these we share, the more likely we are to connect: language spoken; growing up in the same location; educational and career experience; Hobbies and interests; worldview; sense of humour; and musical tastes. The researchers were surprised that musical taste would have such a prominent position, but if we do share this with someone, it means good things for our potential friendship!
- Induction: Few organisations treat induction in a reciprocal way, and education is just as guilty. Most induction processes are first and foremost focused on organisation rather than the recruit. The authors argue that induction falls into a similar pattern: watching videos or talks about the company’s values, vision, history, but rarely is there a reciprocal attempt to connect the identity and background of the new recruit with the identity of the organisation. The book challenges us as leaders to think about how we can think more carefully about how we don’t just emit ideals during induction, but create dialogue. This comes at a time where I have been thinking about more meaningful induction processes in our trust – the first challenge to myself: get some data about what staff actually think!
Some fascinating stats and research insights
Friend at work – good for engagement!: Gallup, the organisational insight expert, has included the question ‘do you have a best friend at work?’ in its engagement surveys for 30 years. They ask this question because the answer turns out to connect to many other metrics about your performance and relationship with the company as a whole; having a best friend helps you to feel more engaged, and that, in turn, helps you to further commit and do better work. Interestingly, of those women who answer yes to the question, 63% are likely to feel engaged at work, compared to only 23% of those who answer no.
Link between friend numbers and depression: a large transnational study found that the chances of someone developing symptoms of depression was less for those who had five close friends. And this trend doesn’t continue as you gain more friends: having more than five friends was increasingly detrimental, probably because social effort was divided among too many people and resulted in friendships that were insufficiently strong. A small number of high-quality friendships is good for us. That’s good news for me and my very small circle 😀
Working conditions and community: One researcher spent time with two groups of male workers who worked nights. One group operated in a food retailers’ warehouse, stacking and packing. The other group worked repairing broken line signals for the train network. Although working conditions for both were apparently fairly poor, the mental health of the railway workers was much better than those of the wealth warehouse workers. The railwaymen did three night shifts in a row, but they worked together as a team in difficult conditions. They ate together, joked together, and supported each other. They worked in a companionable way. The warehouse workers were communicated with through earphones, so they had little opportunity to communicate among themselves. They had separate breaks and worked individually. There was no sense of community because they never sat down together as a group for a coffee or tea. In effect, theirs was the solitary life of a hermit despite being surrounded by other people; their mental health and sleep patterns were worse, and the interviews revealed that their work meant little more to them than wages per hour. In contrast, the rail workers expressed pride in playing their collective part in keeping travellers safe.
Conversation size limits: Research has found that the upper limit on numbers in a conversation is… 4! If more people join, the group of quickly split into separate conversations, often within less than a minute of an extra person joining. As a group size increases, it transforms from a conversation into a lecture, but that usually happens only when there is a dominant individual present who could hold court while the rest listen dutifully in silence.
A second reason for the limited conversation size is that an individual share of speaking time decreases rapidly as the number of people in the conversation increases. If you keep being prevented from having your say, you inevitably lose interest and will begin to look for a smaller conversation.
Synchrony: Researchers monitored the Oxford University rowing crew for a week in training, looking at effort, pain threshold, speed, etc. On the second week, they moved their indoor rowing machines to be in line with each other, like a mock boat to create a sense of ‘synchrony’ during training sessions. Rowing in time with each other dramatically increased their pain thresholds by 100%, despite the same physical effort being exerted. The study highlights the powerful, almost unconscious, bonding mechanism that behavioural synchrony ignites. This isn’t just about feeling good; it’s about measurable biological effects that enhance collaboration and resilience.
Concluding thoughts:
It was hard to write a concise summary of this book – there’s too much research to share on its own, let alone getting into how we connect this with our own teams and organisations.
But what it challenged me on is remember that human beings are complex! We can create the most incredible organisational culture, with deliberate values and mission, and a compelling performance challenge for teams to get stuck into. But we mustn’t forget that there is a huge range of research which points us in certain directions about how people behave in any group. Lots to think about!
Reflective questions:
- Numbers & Structure: Are your teams and departments structured in alignment with Dunbar’s numbers (5, 15, 50, 150)? Are you detecting stress or conflict that might indicate a group size is too large for its function?
- Belonging & Culture: How are you actively creating a sense of belonging within your organisation? Are your foundational stories and rituals inclusive? Does your organisational language reflect the desired culture?
- Bonding & Relationships: Are you actively creating time and space for genuine bonding activities like shared meals or synchronous experiences? How are you fostering ‘friendships’ at work, recognising their link to engagement and productivity?
- Communication & Leadership: Are you truly listening to your employees, especially those at the “edge” of the organisation where new insights emerge? Is your leadership model distributed, empowering leaders at all levels, or is it too top-down and positional?
I’d really recommend this book to anyone in leadership or who is interested in groups and teams.
The Social Brain: The Psychology of Successful Groups. By Tracey Camilleri, Samantha Rockey, and Robin Dunbar.
Sam Crome 