[Terr_]

It's not just empathy in the social buddies sense, but also that -- to quote a study name -- "Higher social class predicts increased unethical behavior."

Abstract: http://www.pnas.org/content/109/11/4086

PDF: http://www.pnas.org/content/early/2012/02/21/1118373109.full...

And yes, there are some hints to causation in there, where a participant was made "wealthier" (in a game context) and then differences were observed.

[Kalium]

If memory serves, there's a critical detail that isn't in this study and wasn't checked by it. "Higher social class" people cheat to help themselves and "lower social class" people cheat to help one another when both are given salient opportunities.

Neither group is more honest than the other.