You might think that your friendships are fated in the stars. They’re actually hardwired in your brain.

That ‘Game of Thrones’ LARPing team you’ve assembled? Your campaign wasn’t as destined as you think. You’re actually sticking together because of a vestigial survival tactic set forth by your mind.

When you LARP, play ball, or watch a movie together, a series of neurochemical interactions occur to draw you and your squad closer to each other. This is all a part of an evolutionary mechanism to help ensure the survival of human offspring. Your ancestors stuck together in order to protect them from a harsh threatening world. The stronger the crew, the longer the life span.

Watch this in-depth explanation of the neuroscience of how and why we make friends.