There’s been a fair amount of press about a new paper in Science that shows how the brain responds to social rejection. The kicker is that a region of the brain known as the insula becomes active. As I mentioned yesterday, that’s the same area that responds to pain and physical distress. It’s an interesting paper with historical dimensions that are missing from the news reports–historical in both the human and evolutionary sense. There’s a lot of back-story behind the word “heartache.”

A common theme in evolution is the way a structure or a system takes on new functions over time. In our “reptilian” ancestors, bones in the jaw were co–opted for conducting sound to our brains; over a