Social lives are delicate things. We've all had situations where friendships and relationships have been dented and broken, and we're reasonably skilled at repairing the damage. This ability to keep our social ties from snapping relies on being able to read other people, and on knowing a thing or two about what's normal in human society.
For instance, we appreciate that cheating fosters ill-will, while generosity can engender trust. So cheaters might try to win back their companions with giving gestures. These little exchanges are the glue that bind groups of people into happy and cooperative wholes. Now, a new study uses psychological games and brain scans to show what happens when they go amiss.
