In the category of “things that are probably very obvious and well-established, but that I didn’t figure out until just now” –

The conventional wisdom suggests that physical attractiveness plays such a huge role in romantic / sexual selection, especially for men-selecting-women, because the people making the selections really care a lot about it relative to other possible priorities.  But it seems very likely that, in large part, it carries so much weight because it’s easy to gauge accurately and quickly. 

This is probably true even if you’re talking strictly about private internal prioritization.  It doesn’t matter how much you really want a Nice Girl with a Good Personality if you can’t tell what a given girl’s personality is like.  And, sure, that’s the sort of thing you’re going to figure out eventually, but it really is genuinely hard to separate the signal from the noise on the first date, let alone in the first minute.  People put a lot of effort into making good first impressions, which translates to “sending deceitful signals about what they’re like” – often they’re not even doing it consciously, it’s a natural part of human interaction.  You certainly can’t tell early on how someone is going to react to a variety of uncommon-but-important stressors.  But you can certainly tell whether she seems hot.  Makeup and flattering clothing etc. do serve as signal-jammers here, but they’re honestly not very good ones, not compared to our social-chameleon powers. 

The phenomenon takes on a lot more salience, though, when you start thinking of your mate as a status symbol.  Which is, of course, a big part of how many people approach the world.  However they might posture, it’s not that the guys at the office don’t understand or appreciate the virtues of a good personality – but you nonetheless can’t usefully brag about your girlfriend’s excellent personality, because it’s basically impossible to verify.

I’m still sorting out the way this plays out with the traits that women stereotypically find important in their male romantic / sexual partners, but I’m pretty sure it’ll be feasible to draw close parallels.

[Exploring the parallels between this stuff and hiring practices is left as an exercise for the reader.]