David Ropeik tells the story of an attorney who gave birth during a Philadelphia Eagles championship game. The woman was such an Eagles fan that she insisted on watching the game through her delivery. The Eagles won that day and in the new mother’s mind, the win was intimately tied to the birth of her child. Now, in order to get her team to the Super Bowl, the mother is considering having another baby and timing the delivery for the playoffs. Nothing better demonstrates the extent and reach of our fan loyalty, says Ropeik, and the reason is deeply related to our latent tribal instincts.

David Ropeik: An attorney, a woman, married to a therapist, delivered a baby and was such a Philadelphia Eagles fan that she literally watched the game while she delivered the child. The team won. They haven't won since. She's thinking of having another baby to time it to the playoffs just in case. Is there a more perfect example in the world of our surrogate warriors going to battle in the name of our tribes and how rabidly we need to belong to and demonstrate loyalty in our tribe than the penultimate sporting event, the Super Bowl? We, as social animals, depend on our tribes, our groups, the groups of people with which we most affiliate for our safety and our survival. We can't protect ourselves from the lion if the lion is attacking, but together we can. So we do lots of things to demonstrate loyalty to our various tribes, our political tribes, our religious tribes, our gender, or our age. Well, our tribe of team, mostly based on geography, but a little bit on history where we grew up, let's say, that's exactly their role. They are the surrogate representatives of going to combat in the name of our tribe. So go Patriots in my case, but they're out of it. Go Denver. Go Carolina. Go Red Sox. Go Yankees. It's surrogate for, "Go my group," which demonstrates loyalty to the group, which makes the other people in your group like you. If you're a Denver fan and you're living in New England, you're going to get kicked out of the party. And social cohesion helps your group do better against other groups. So in politics that helps your party win, but in sports, you pretend you're the 12th man. You can affect the outcome by how loudly you scream or how you sit on the chair or did you wear your lucky hat or did you have omelets, your lucky omelets for breakfast? It's a classic example of how humans depend on their tribe and their social sense of belonging for their own sense of safety and literally survival.