Dunbar Number
A cognitive limit to the number of people with whom one can maintain stable social relationships, in which an individual knows who each person is and how each person relates to every other person.
The study shows that:
- Close relationship: 5 people.
- Share deep trust: 15 people.
- Meaningful relations: 50 people.
- Active contacts: 150 people.
Why is this limit 150?
This is due to the limit of our cognitive ability. This is our ability to reason, solve problems, and comprehend complex ideas. As the team size increases, the cognitive load of the team does it as well and communication suffers, thereby breaking down the benefit of a large team.
Origin
In the 1990s, the British anthropologist Robin Dunbar found a correlation between primate brain size and average social group size. By using the average human brain size and extrapolating from the results of primates, he proposed that humans can comfortably maintain 150 stable relationships. Dunbar theorised that:
“this limit is a direct function of relative neocortex size, and that this, in turn, limits group size […] the limit imposed by neocortical processing capacity is simply on the number of individuals with whom a stable inter-personal relationship can be maintained”.
The number also includes past colleagues, such as high school friends, with whom a person would want to reacquaint themselves if they met again.
How is this related to Teams?
- Single teams: 5-9 people.
- There is a shared trust among the team members.
- The trust is build among time.
- Therefore, they must be a long term team.
- Group: 50 people.
- They can have meaning relationship.
- They share a domain or subdomain.
- They understand the challenges and help each other out.
- Division: 150 people