While studies of SM are lacking, other activities involving inflicting pain are shown to reduce empathy. Examples include violent video games (study) and fighting in a war (article). I don't have a source for sociability impact beyond my self-interested desire to avoid people who enjoy causing pain.
Maybe those are not comparable. E.g. anna anthropy writes
you think about violence differently when it’s asked for, and when the person receiving it is someone that you care about – it has consequences. you start checking in, paying attention to her physical and emotional state.
Previous Open Thread: http://lesswrong.com/r/discussion/lw/k94/open_thread_may_19_25_2014/
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