The Dominant Move

Why is betrayal so hard to resist? Because it is a dominant strategy: no matter what your partner picks, betraying leaves you better off than staying silent would have.

If your partner cooperates, betraying lets you walk free instead of serving a year. If your partner betrays, betraying back saves you from the worst sentence. Either way, betrayal wins for you alone. Both players see this, both betray, and they land in the one outcome neither truly wanted — a trap built from flawless logic.

More Trusting Than the Math

Here is the hopeful twist: real people cooperate far more than the cold theory predicts. In experiments, strangers playing for real money stay silent at rates the pure logic says they never should.

Why? We carry habits built for repeated life — we read faces, value our reputation, and feel the sting of guilt. Evolution shaped us for a world of return encounters, not one-shot lab games. Our instinct to trust is, in a sense, smarter than the equation.