Lots of people choose luxury over saving 28 lives. Doing so may be wrong, but if it's that common, it can't be strongly indicative of sociopathy.
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 :)
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: