Jim talks to Robin Dunbar (of Dunbar's number) about his new book, Friends: Understanding the Power of our Most Important Relationships... Jim talks with evolutionary psychologist Robin Dunbar, discoverer of Dunbar's number, about his latest book, Friends: Understanding the Power of our Most Important Relationships. They cover the importance of friendship, the loneliness epidemic, loneliness as a signal rather than a disease, oxytocin & endorphins, physical touch, synchrony & other ways of triggering the endorphin system, new data sources in the study of social networks, the social brain hypothesis, theory of mind/mind-reading, limitations of our mind-simulating capacities, the discovery of the Dunbar number(s), examples of the pattern from Navy Seals to Christmas cards, the mystery behind the scaling law of three, the seven pillars of friendship, costs & benefits of diversity, why friendships end, and more. Episode Transcript Friends: Understanding the Power of our Most Important Relationships Dunbar’s number Framingham Heart Study “Toward a Neurology of Loneliness” - by John Cacioppo & others Robin Dunbar is Professor of Evolutionary Psychology at the University of Oxford, an Emeritus Fellow of Magdalen College, and an elected Fellow of the British Academy and the Royal Anthropological Institute. His principal research interests focus on the evolution of sociality (with particular reference to primates and humans). He is best known for the social brain hypothesis, the gossip theory of language evolution and Dunbar’s Number (the limit on the number of relationships that we can manage). His publications include 15 authored or edited academic books and nearly 550 scientific journal articles. In addition, he has published a great deal of science print journalism in newspapers and magazines, and 11 popular science books.