• Dunbar’s number suggests that humans can maintain about 150 relationships at a given time 
• Humans have spent most of our lives in smaller, hunter-gatherer groups; existing together in large cities is a relatively new thing for the species 
• The best predictor of your mental and physical health – in addition to how long you are going to live into the future – is the number and quality of your closest relationships 
• There is a correlation between the number of friends people claim to have and the size of certain regions in their brains 
• “If you really want to live forever, just make sure you have five friends.” – Robin Dunbar 
• The emotional closeness of a relationship is highly correlated to the amount of time invested in it 
• Laughter, singing, and storytelling are how we foster emotional closeness with others without physical touch 
• Homophily is the tendency for people to seek out or be attracted to those who are similar to themselves; this is the driving force behind friendships 
• Face-to-face relationships are paramount: there is a significant difference between bonding with something in your head and with someone in the real world

My guest today is Robin Dunbar. Robin is a biological anthropologist, evolutionary psychologist, and specialist in primate behavior. He is the man behind Dunbar’s number, a theory about the number of stable relationships we can maintain at once. Robin unravels the thread of research that led him to Dunbar’s number and describes how this plays into every single person’s layers of human connection. It was fascinating to hear how his findings on social circles have implications for optimally structuring businesses and organizations, as well as the idea of homophily, all of which Robin thoughtfully explains. It was a treat to get to explore these topics with Robin Dunbar himself so please enjoy this great conversation.  

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