I reviewed the findings of what may be the only scientific study of what psychological traits belong to men who prefer boobs, ass, or legs. The Boobman appears to be a gregarious "guy's guy," while the Assman seems more like the Type A businessman or leader. *
Just thinking it over, I discovered that geeks are predominantly Boobmen. The converse is not true, but I have a hunch that the average "geek score" among Boobmen would be higher than among Assmen. Think of guys who watch cartoons, especially Japanese ones, and play video games during most of their leisure time. Cartoon girls who are meant to look sexy always have big boobs, and little or no ass -- just see any Anime female, or the Lara Croft character from the video game Tomb Raider. Their creators must know what their audience likes.
Are badboys more likely to be Assmen? It seems so. First, the only cartoon girls I've ever seen who had big butts are from the video for Weird Al's "Close But No Cigar", in which a Byronic badboy cannot restrain himself from berating his girlfriends. The three pickup artist bloggers who I read are all Assmen (Roissy, RooshV, and Virgle Kent). If anyone's read all 3500 pages of Casanova's memoirs, does he suggest whether he's an Assman or not? Or other famous libertines?
If there are any criminologists reading this, are violent criminals more likely to prefer buttocks to boobs? I googled and couldn't find anything, but maybe there is anecdotal evidence.
In trying to recall all instances of a female remarking on another female's looks, I think I've never or rarely heard something like, "Woah, she's got a hot ass," but have heard "She has really nice breasts." And I mean when the female observer makes this remark spontaneously -- what does she notice and feel moved to comment on? Obviously if the conversation is already about Jennifer Lopez, she will say "By the way, she's got a pretty big booty, huh?"
On a population level, the correlation holds (compare Africans, Europeans, and Asians, or Mediterraneans vs. Scandinavians), but that doesn't mean it holds on an individual level.
One possible source of all of this variation (established or conjectural) is level of testosterone. It would be pretty easy to set up a study on college males to see if preference for boobs vs. buttocks correlated with levels of salivary testosterone, or if that's too expensive, then their digit ratio. Clearly, more research is needed.
Another interesting line of research would be to see what traits women with larger breasts vs. larger buttocks had. If Assmen tend to be more Type A, and if they get what they're after, then the daughters of such a marriage would inherit both big butts and a feisty personality. Similarly, the daughters of a Boobman and woman with large breasts would be buxom and gregarious or chatty. So maybe a girl's shape tells you something about her personality or behavior. These patterns would hold at the population level, not necessarily at the individual level, since they would result from cross-assortative mating.
Come to think of it -- have you ever seen a wet t-shirt contest or a "booty battle"? It could have been in person or on TV, as long as it wasn't fictional or they were put up to it (like in a strip club). The wet t-shirt girls try to play up their girliness, coyness, or ditziness, whereas the girls who volunteer for the booty battle are definitely more competitive and feisty. And just think how incongruous the phrase "boobie battle" would sound.
* Giving new meaning to the letters in Type B vs. Type A.