SlateStarCodex is one of my oft visited sites. Scott tends to put time and thought into interesting questions. Even when/if I disagree with any particular thing, there's always a good conversation involved.

Sometimes, though, there are bits and pieces missing from both the arguments Scott presents, and the commenters who noodle his arguments in the conversation that follows. This post on how, or whether, breasts and human sexual response generally, reconciles with what we know or don't know about evolutionary psychology, is one example that I stumbled on.

It's nothing major, and it took me a while to realize what I was missing. At least one commenter mentioned the fact that humans don't generally know by looking (or smelling, or whatever) when females are ovulating. Unlike the rest of the mammalian family. I thought at first, cool, that's something like it.

But then I realized that can't be the whole answer. And I searched the post and comments for the phrase "sexual maturity", and came up empty.

That is, in a species where noone can tell when a female is in estrus, the standard mammalian (lack of) visible breasts won't do. There's not much physical distinction between human females before and after puberty, structurally speaking. Breast size and hip size are the most immediately visible means of distinguishing.

Note, I don't say this is the only explanation. It just occurs to me that it should likely be an important part of the mechanism as a whole.