"I Feel Your Pain"

Fascinating:

The ability to appreciate other people's agony is achieved by the same parts of the brain that we use to experience pain for ourselves.

They shocked a bunch of women's hands and took an MRI, which showed both sensory and emotional regions of the brain lit up. Then they made them watch their partner get shocked in the hand and took an MRI of that. The same emotional response showed from watching the shock, though it was reduced when they couldn't see the registration of pain on the face. The degree of emotional response increased as the emotional bond between partners increased.

(via Marginal Revolution)