This may seem a bit off, but I'm actually a voice kind of guy. A prime example of this is the girl I'm currently umm, "into", I first started "crushing" on her when I heard her speak. Since then its also expanded to her personality, the way she dresses, the way she looks. But it all started with her voice, and I still get shivers when I hear it.
And now that I think about it, most of my friends have voices that I find not too unpleasurable.
So I think that your preferences have SOME correlation to the way you learn, every person has preferred learning styles. For example, I am a heavily audiographic learner, and I forget almost nothing that I hear. Consequence that I also find voices attractive/unattractive? I mean, everybody has voices they like, but probably not so radically as this.
Which would mean that people who are attracted to breasts/boobs would more likely be textile learners (I believe thats people who learn with their hands, or by manipulation of objects, etc..). Which I think also corresponds to the ratios I've seen (I.E - Most people are textile learners).
Idunno, just speculation.