The Neuroscience of the Debt Debate... Seriously!!

"In fact, around 50 percent of prisoner's dilemma games played by real people end in mutual cooperation, with both partners showing tight-lipped solidarity. In essence, our brains seem primed for a level of cooperation beyond what's theoretically in our rational best interest. Without this bias, our species may never have struck on such fundamentally trust-based behaviors as reciprocal food sharing—a thought that puts present political squabbles into perspective.

To put it another way, the neural operations in social decision-making involve calculating trust as well as implementing strategy. In support of this claim, several recent functional MRI brain scanning studies have shown that activation of the ventral striatum—a deep structure in the forebrain—predicts the intention to trust a partner in games similar to the prisoner's dilemma."

- More Here or just call it ego games.