How Wealth Reduces Compassion: Scientific American
http://www.scientificamerican.com/article.cfm?id=how-wealth-reduces-compassion

But why would wealth and status decrease our feelings of compassion for others? After all, it seems more likely that having few resources would lead to selfishness. Piff and his colleagues suspect that the answer may have something to do with how wealth and abundance give us a sense of freedom and independence from others. The less we have to rely on others, the less we may care about their feelings. This leads us towards being more self-focused. Another reason has to do with our attitudes towards greed. Like Gordon Gekko, upper-class people may be more likely to endorse the idea that “greed is good.” Piff and his colleagues found that wealthier people are more likely to agree with statements that greed is justified, beneficial, and morally defensible. These attitudes ended up predicting participants’ likelihood of engaging in unethical behavior.