In this episode of My Idiot Brother Questions Everything, we discuss Tribalism: it’s not just for cavemen with spears anymore. We dive into how our “team spirit” can hijack our brains and short-circuit critical thinking. We start in ancient Greece, where Sparta and Athens bickered like rival sports fans, then fast-forward to the tragic and deadly Hutu–Tutsi conflict to show how powerful—and dangerous—tribal identity can be.

Jump to today’s U.S. politics and you’ll see the same instincts at work. Democrats and Republicans act like dueling fandoms, even though hardly anyone’s personal beliefs line up perfectly with their party’s platform. Yet we still pick a side, put on the jersey, and join the echo chamber.

We talk about how that echo chamber hardens our thinking, makes us allergic to nuance, and turns “the other side” into a caricature instead of a person. And we explore the high cost of that dehumanization—for our politics, our communities, and our own ability to think for ourselves.

If you’ve ever wondered why smart people act like superfans for bad ideas—or why you sometimes do it yourself—this episode will make you laugh, squirm, and (hopefully) rethink your own tribal instincts.