Lots of people let akrasia, compartmentalization, etc. keep themselves from realizing that it's actually a choice. When they're put side by side and the answer is a casual "of course I'd choose my own life", I tend to consider that stronger evidence of sociopathic behavior.
That said, yes, I consider most people to exhibit some degree of sociopathic behavior. LessWrong just demonstrates more :)
I'm inclined to agree with steven0461,
Lots of people choose luxury over saving 28 lives.
Actually, this is true even for rather low values of "luxury". I, like tens of millions of other people in the developed world, am a homeowner. Yes, the cost of my (rather modest) home would have saved ~100 lives if I had instead donated it to a maximally effective charity. That isn't what I did. That isn't what the other tens of millions of homeowners did. If you want to count that as sociopathic behavior, fine. But that casts a rather wide net for ...
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: