Let's talk about Dunbar's number.
🤔 Why you should care about it
"British anthropologist Robin Dunbar theorised that a typical person can't easily have more than 150 people in his tribe. After 150 friends and fellow citizens, we can't keep track. It's too complicated." - Seth Godin, American author, in Linchpin.
According to British anthropologist Robin Dunbar, the maximum number of social relationships a human can effectively manage is 5 for close friends, 15 for good friends or teammates, 50 for casual friends and colleagues and 150 for communities with a very high incentive to remain together.
In the context of organisations, Dunbar's number has been used as a reference point to help understand the size and structure of teams and their potential impact on team dynamics and communication.
😫 Problem(s)
Communication breakdowns —> team members that cannot build close relationships with each other spend too much time communicating or finding the right person within the organisation.
Decreased performance —> coordination becomes vastly more challenging as organisations grow, creating decreased performance even if individuals give their best at their level.
Team member dissatisfaction —> team members' satisfaction and engagement are highly correlated with the ability to have meaningful relationships with colleagues.
😃 Solution
Leveraging Dunbar's numbers to size teams, leaders should aim at having:
- Teams of 4 to 8 people that work together daily on a common goal (the infamous two-pizza team);
- Groups (or tribes) of 10 to 20 people that collaborate to achieve common objectives;
- Departments of 40 to 60 people coordinate to deliver a common strategy;
- Organisations of 140 to 160 people that work together to accomplish a joint mission;
Above 150 people, organisations should have different purposes and limit interactions altogether.
💡 Key Concepts
Social network structure —> human social networks have a structure, with individuals having different relationships with others in their network.
Community building —> the process of creating and maintaining a sense of belonging and connectedness among a group.
Social group sizing —> the process of determining the appropriate size of a social group based on the number of individuals with whom they can effectively maintain stable social relationships.
😡 Detractors
"The Dunbar numbers are artificial cognitive limitations that depends vastly on people and environments." —> while the numbers may not be a strict limit, it helps to have a theoretical framework for organisational design. In practice, teams could be more significant if need be.
"Technology, effective communication tools, processes, and more mitigate Dunbar's cognitive limits." —> while technology can help to improve communication and collaboration within groups, it may also introduce new challenges and difficulties, such as information overload and decreased face-to-face interaction.
"Being small is not the biggest predicator of a team's success." —> this is correct; the most significant predictor of a team's success is having a leader with the necessary skills, authority, and prior experience to assemble and oversee a team dedicated to reaching its objectives.
📚 Top book
Friends: Understanding the Power of our Most Important Relationships - Robin Dunbar
🗂 See also
📝 Top content
Dunbar's Number and Team Size - Psychological Safety
Social group sizes, Dunbar's number and implications for communities of practice - Emily Webber
Sizing engineering teams - Will Larson