Where is the dividing line between you and the world?

Where is the dividing line between you and the world? Like all animals, humans also protect themselves from potential threats by keeping them at a distance. Those of us beginning to see friends again after months of pandemic-induced social distancing can feel this at a visceral level, as we balance the desire for contact against a sense of risk. Once we evaluate something as a potential threat – even if that assessment is informed by public policy or expert prescription – there’s a powerful urge to maintain a buffer of space.

This buffer is a byproduct of our evolutionary history, which has equipped our brains with a way to acknowledge and track the importance of our immediate surroundings. That mechanism is known as peripersonal space, the region in and around a person’s body (peri comes from the Ancient Greek meaning ‘about’, ‘around’, ‘enclosing’ or ‘near’). Peripersonal space exists in various forms across the animal kingdom, from fish and fruit flies to wild horses and chimpanzees. The neuroscience behind it sheds fascinating light on how humans and other animals conceive of themselves and their boundaries. Where is the dividing line between you and the world? You might think that this is a clean-cut question with a simple answer – your skin is the boundary, with the self on one side and the rest of the world on the other. But peripersonal space shows that the division is messy and malleable, and the boundary is blurrier than you might think.

The peripersonal zone is a nexus where space, time and survival are tightly bound together. Maintaining a buffer of peripersonal space is important because it gives an animal time to react to a threat before it’s too late.