Interesting responses so far, thanks for participating. For those who answered biological, I know its hard to try to imagine, but do believe that if you grew up with the Yanomami tribespeople in Venezuela for example where breasts are not covered, you would have the same perception about breasts?
Question two: If you were to go live with the Yanomami tribespeople right now for five years with your current beliefs, do you think you would be in a perpetual state of slight arousal because your brain would make the constant associations of boobs/sex?
BTW, please lets not get into the debate of tribal breasts vs. non tribal breasts. If you are truly biologically wired to like boobies, it shouldn't matter, unless you believe you were culturally conditioned to like certain type of boobies like victoria secret or hooters boobs.