Swede Success

An elemental, if not terribly exciting, piece of science outta, well, Sweden, finds that, yes, having a common past experience makes us more empathetic with someone. 

Subjects read stories, some of which mirrored their own lives, and rated the degree of empathy they felt.

Maybe that's the reason why, when comforting others, we tend to bring up similar situations we were in (my mother also died; I too divorced), not to make the other person feel better, or hog sympathy for ourselves, but to try to trigger our own sense of empathy.