Dunbar's Number and Operating Model Design👇🏽

Robin Dunbar, Emeritus Professor of Evolutionary Psychology at Oxford, studied how social bonds form in primates and humans. His work helps us understand the limits of social relationships and their impact on team cohesion, trust, and structure.

His research provides insights into the mechanisms that underpin social relationships and how they have enabled humans to create large-scale societies despite our evolutionary origins in much smaller groups.

Dunbar identified the limits of human social relationships. These limits are not rigid but rather approximate boundaries that can vary depending on various life contexts—such as family, work, or social environments.

In each context, individuals can maintain similar group sizes, suggesting that our capacity for relationships is not a single pool but rather divided across different spheres of life.

These insights are valuable when designing modern operating models:

~𝗙𝗜𝗩𝗘 𝗽𝗲𝗼𝗽𝗹𝗲: This is the limit of individuals with whom we can maintain close personal relationships. These are the people we confide in, and they occupy much of our emotional energy.
~𝗙𝗜𝗙𝗧𝗘𝗘𝗡 𝗽𝗲𝗼𝗽𝗹𝗲: This is the number of people we can experience deep trust—those with whom we share a meaningful connection and extended support.
~𝗙𝗜𝗙𝗧𝗬 𝗽𝗲𝗼𝗽𝗹𝗲: This is the limit for mutual trust relationships. We may not be deeply intimate with these people, but we know them well enough to count on them.
~𝟭𝟱𝟬 𝗽𝗲𝗼𝗽𝗹𝗲: Often referred to as Dunbar's Number, this is the cognitive limit for the number of individuals whose capabilities, roles, and relationships we can remember and navigate effectively.

When designing an effective operating model, these numbers serve as valuable guideposts:

▶️ 𝗧𝗘𝗔𝗠𝗦: Based on industry experience, an effective team size is around five to eight people, ensuring each member can maintain close working relationships. In high-trust organisations, teams of up to fifteen people can still maintain trust and cohesion.

▶️ 𝗧𝗘𝗔𝗠-𝗢𝗙-𝗧𝗘𝗔𝗠𝗦: Teams can be grouped into units of around fifty people—an ideal scale for maintaining mutual trust across different subgroups. In high-trust organisations, this number could go up to 150 people while maintaining collective familiarity and cohesion.

Dunbar's research helps us understand why larger teams struggle with cohesion and why maintaining smaller groupings is crucial for scalability.

Designing around these numbers can enable better communication, stronger bonds, and more effective and nimble structures.

💬 What's the size of your team today? How does it compare to Dunbar's suggested limits for fostering trust and cohesion?👇🏽