I wonder if you are more or less likely to use a slur when you have exposure to the minority group? I would hope less. I suppose it would have to do with the type of exposure. If you work with someone that is a minority closely, or have a neighbor you interact with regularly, this is different than just seeing people on a subway etc. My guess is that it's difficult to dislike people out of hand because of the pigment in their skin when you actually know someone with that pigment affliction.
Ohio Valley checking in. I moved here from California, and the open racism was not something that I expected. As a pale older white Irish guy, the locals think they can spout off racism as if we are talking about the weather. It is also significantly more segregated here than what I am used to. White and black people simply do not mingle, or even share the same spaces it seems; this is bad for all of us as the more you meet and interact with people who are different than you, the less bigoted you tend to be.