Evolutionary psychologist Robin Dunbar discusses the power of friendship, the loneliness epidemic, oxytocin and endorphins, new data sources in social networks, the discovery of Dunbar's number, the seven pillars of friendship, and why friendships end.
Investing time and effort into friendships is essential for building a support network that can provide emotional, social, and even financial help when needed.
The size of the neocortex is proportional to the size of an individual's social group, with around 150 being the estimated limit for meaningful relationships.
Engaging in convivial activities like laughter, singing, dancing, and feasting triggers the release of endorphins, which promote bonding and positive emotions.
Friendships have a natural cycle and typically don't last more than about 10 years, with a constant turnover in friendships.
Deep dives
Importance of Friendship for Well-being and Longevity
Loneliness is becoming a common cause of death and has negative impacts on mental and physical health. Research has shown that having close friendships and social connections is crucial for overall well-being. Loneliness negatively affects the immune system and increases the risk of depression, Alzheimer's, and physical diseases. Engaging in convivial activities like laughter, singing, dancing, and feasting triggers the release of endorphins, which promote bonding and positive emotions. Investing time and effort into friendships is essential for building a support network that can provide emotional, social, and even financial help when needed.
The Social Brain Hypothesis
The social brain hypothesis explains why monkeys and apes have larger brains compared to other species. It suggests that the complexity of their social relationships necessitates larger brains to manage the computational demands of maintaining social connections. The mentalizing circuit and default mode neural network in the neocortex play crucial roles in understanding the thoughts, emotions, and intentions of others. Humans, as well as other social animals, rely on these brain networks to navigate social environments, build relationships, and maintain social cohesion. The size of the neocortex is proportional to the size of an individual's social group, with around 150 being the estimated limit for meaningful relationships.
The Influence of Neuromodulators
Neuromodulators, such as oxytocin and beta endorphins, play important roles in social bonding. Oxytocin, often referred to as the 'love hormone,' facilitates maternal-infant bonding and romantic relationships. However, beta endorphins are found to be more powerful in building friendships and social connections. Stroking, cuddling, laughter, singing, dancing, feasting, and other communal activities trigger the release of beta endorphins, promoting bonding, trust, and happiness. These activities provide opportunities for synchronous behavior, enhancing social cohesion and creating a sense of community.
The Dunbar Number and Group Sizes
The Dunbar number refers to the suggested cognitive limit of approximately 150 meaningful relationships an individual can maintain. This concept arose from the correlation between primate brain size and group size. Humans, as primates, have built-in limitations due to the size of our neocortex and the constraints of childbirth. Traditional hunter-gatherer societies typically live in communities of around 100 to 200 individuals, reflecting the approximate size of the Dunbar number. This number is supported by studies on village sizes, social networks, and historical data, consistently revealing the significance of 150 as a relevant group size for humans.
The Natural Cycle of Friendships
Friendships have a natural cycle and typically don't last more than about 10 years. There is a constant turnover in friendships, and about a third of all friendships change every year, with the turnover being faster in the late teens and 20s. Even in midlife, there is still a constant turnover. Friendships that drift apart slowly tend to be more common, while catastrophic failures in close relationships, such as with parents or romantic partners, are more difficult to repair and often result in irreconcilable rifts.
The Seven Pillars of Friendship
Friendships are characterized by similarities and shared traits, forming what is known as the seven pillars of friendship. These pillars include factors such as speaking the same language or dialect, growing up in the same area, having similar educational trajectories, sharing hobbies and interests, having a similar worldview, sharing musical taste, and having a similar sense of humor. The more pillars of friendship that are shared, the stronger the friendship tends to be.
Diversity and Homophily
Diversity and homophily both have benefits and costs in social relationships. While diversity can bring cultural benefits and innovation, homophily, or similarities between individuals, can lead to stronger bonds and more efficient interactions. It is important to strike a balance between diversity and homophily, as too much diversity or homogeneity can have negative effects on social relationships.
The Fracturing of Family Relationships
Family relationships, including those between parents and offspring, can experience fractures and irreconcilable rifts. Friendships that occur within the family unit can suffer due to disagreements about inheritances, responsibilities, and end-of-life arrangements. Issues of scale and the limitations of managing relationships within a family unit can contribute to these fractures, especially when the parent is no longer present to provide a sense of obligation. The added stress of death and funeral arrangements can exacerbate and permanently fracture family relationships.
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.
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