This is the first study I've seen that explicitly claims that people in higher social classes are more unethical than those from lower classes; furthermore, the authors claim that this tendency is "accounted for, in part, by
their more favorable attitudes toward greed." Aside from the well-known problems from the so-called "sophomore problem," this is a compelling and disturbing study that warrants replication in other contexts (based on, for instance, observational data from other populations).