The old canard about the major histocompatibility complex (MHC, no great links; just google it) and attraction is that there's a pheromone-mediated bias towards dissimilar MHCs, in the service of allelic diversity. Sure, I'd always thought, for other people. For me, I'd generally opted for the more explicitly cognitive similarity-promotes-liking mechanism, especially since some of the psychological research in that area is mine {cough}.I'm inclined to think that it's possible to have both.
Here's the thing, and it's something you don't see discussed in the MHC literature too much: these two attractors are largely at odds. To put it in current and concrete terms: what are the chances that a blue-collar (-roots) Catholic guy from Wisconsin is going to get my Alvy Singer reference? And, more dispiritingly: do I really have to choose between shared cultural allusions and a touch that inexplicably makes me melt?
Unrelatedly: Megan has a resolution.