Recently had an exchange with a correspondent on "runaway sexual selection," and I thought I'd put up this link to a verbal exposition on the process. Here is a short paper from 6 years back with a more mathematical treatment in the context of ornamentation. Relevance? Runaway might be why some populations look so ooogggllly to you, but they get on fine with each other, their "ornaments" are your ugly masks.

Addendum: A short paper by Geoffrey Miller which presents the core of his thesis about sexual selection & humans elaborated in The Mating Mind.

Related: The Wisdom of Seinfeld.