Image of the front cover of The Social Brain

Leading by the numbers – the psychology of successful groups

How do groups bond, earn trust and create shared identities? How can leaders build environments adaptable enough to respond to shocks and still enable people to thrive together?

In The Social Brain, authors Tracey Camillieri, Samantha Rockey and Robin Dunbar (of Dunbar number fame) explore “the psychology of successful groups” (which is also the subtitle of the book).

Blending insights from Dunbar’s research into the biological and psychological constraints of the human brain and their effects on our ability to form and maintain relationships with the empirical experience of Camillieri and Rockey, this book is an excellent exploration of the value and challenges of group formation and development. Their Thrive Model (TM) explains how the 6 dimensions of Connection, Belonging, Purpose, Values, Learning and Culture contribute to performance, and the Dunbar graph is used to demonstrate the right sizes for teams with a variety of different functions.

For students of the role of relationships in group performance, this book brings the biological to bear, centred on the Dunbar number – 150 – which is the number of people each of us can maintain meaningful relationships with at any one time. In addition to this hard biological limit, the authors identify and consider other numbers, noting a rule of three, with effective groups settling at 5, 15, 50, 150, 500, 1,500 and 5,000.