Ooh, I'd like to be Pavlov's little puppy in *that* experiment!

I think a tolerance for pain can be built up, and association is important. An inexperienced sub, unless he or she naturally likes pain, has only ever experienced pain in a negative sense, as something that should be minimized and avoided. To experience it and, rather than avoiding it, to *embrace* it, is something of a mental exercise. For me, it's been helpful to take small amounts of pain and remember that it's safe, it won't damage me, it won't go further than I can handle it; to just rethink it as something given in love rather than in anger or whatever.

I don't know if this answers the original question--sounds like maybe it's a moot point now--but this is definitely an interesting topic.