You Are the Sum of Your Friends
Human evolution made social bonds more primal than personal identity
Human social cohesion is supported by subtle biological processes and feedback mechanisms. Like trees that communicate through their root systems, human beings have developed elaborate mechanisms to connect and share with one another.
Our nervous systems learned to treat our social connections as existentially important — life or death. Threats to our relationships are processed by the same part of the brain that processes physical pain. Social losses, such as the death of a loved one, divorce, or expulsion from a social group, are experienced as acutely as a broken leg.
Managing social relationships also required humans to develop what anthropologists call a “theory of mind” — the ability to understand and identify with the thinking and motivations of other people. From an evolutionary perspective, the concept of self came after our ability to evaluate and remember the intentions and tactics of others. Unlike the relatively recent cultural changes that encouraged ideas of personal identity or achievement, our social adaptations occurred over hundreds of thousands of years of biological evolution. Enduring social bonds increase a group’s ability to work together, as well as its chances for procreation. Our eyes, brains, skin, and breathing are all optimized to enhance our connection to other people.
Prosocial behaviors such as simple imitation — what’s known as mimesis — make people feel more accepted and included, which sustains a group’s cohesion over time. In one experiment, people who were subtly imitated by a group produced less stress hormone than those who were not imitated. Our bodies are adapted to seek and enjoy being mimicked. When human beings are engaged in mimesis, they learn from one another and advance their community’s skill set.
The physical cues we use to establish rapport are preverbal. We used them to bond before we ever learned to speak — both as babies and as early humans many millennia ago. We flash our eyebrows when we want someone to pay attention to us. We pace someone else’s breathing when we want them to know we empathize. The pupils of our eyes dilate when we feel open to what another person is offering. In turn, when we see someone breathing with us, their eyes opening to accept us, their head subtly nodding, we feel we are being understood and accepted. Our mirror neurons activate, releasing oxytocin — the bonding hormone — into our bloodstream.
Human beings connect so easily, it’s as if we share the same brains. Limbic consonance, as it’s called, is our ability to attune to one another’s emotional states. The brain states of mothers and their babies mirror each other; you can see this in an MRI scan. Limbic consonance is the little-known process through which the mood of a room changes when a happy or nervous person walks in, or the way a person listening to a story acquires the same brain state as the storyteller. Multiple nervous systems sync and respond together, as if they were one thing. We long for such consonance, as well as the happy hormones and neural regulation that come with it. It’s why our kids want to sleep with us — their nervous systems learn how to sleep and wake by mirroring ours. It’s why television comedies have laugh tracks — so that we are coaxed to imitate the laughter of an audience of peers watching along. We naturally try to resonate with the brain state of the crowd.
These painstakingly evolved, real-world physical and chemical processes are what enable and reinforce our social connection and coherence, and form the foundations for the societies that we eventually built.