The Relationship Between Effort and Morality

We're all trying to surround ourselves with people who will help us out in the pinch. As a result, inequality which makes you a better cooperation partner is seen as a moral quality. The evolutionary psychologists call this partner choice. It's why you're more likely to donate to your friend who pledges to run a marathon for cancer research than your other friend who pledged to watch a sex in the city marathon on TV.