Robin Dunbar is the world-renowned psychologist and author who famously discovered Dunbar’s number: how our capacity for friendship is limited to around 150 people. On March 11 he comes to Intelligence Squared to explain why friends matter to us – more than we think. The single most surprising fact to emerge out of the medical literature over the last decade or so has been that the number and quality of the friendships we have has a bigger influence on our happiness, health and even mortality risk than anything else except giving up smoking.

Exploring the themes of his new book Friends, Dunbar will explain the way different types of friendship and family relationships intersect, the complex of psychological and behavioural mechanisms that underpin friendships and make them possible – and just how complicated the business of making and keeping friends actually is.

Mixing insights from scientific research with first person experiences and culture, he will share his insights from disciplines ranging from psychology and anthropology to neuroscience and genetics.