First, I'd like to thank Oddthinking for calling me out on the flaws in my first response to this. Of course that response took me five minutes and this one took me 90 minutes :). Hopefully, you'll find this a bit more informative.
In 2011, Paul Piff and others released a paper summarizing studies that purport to show that "that upper-class individuals behave more unethically than lower-class individuals". Piff's paper can be found at http://www.pnas.org/content/109/11/4086.full. I find this work to be flawed in many ways which I intend to enumerate below. I don't intend for this to be a full, systematic analysis, as I find that a partial review is enough to discount that papers position.
One consistent problem with Piff is that he frequently displays narrow and opinionated ideas of ideal behavior. He does not spend any time at all discussing any sort of foundation of ethics. But his paper often relies on ideas founded in ethics. For example, we find this early in the paper:
"upper-class individuals’ unethical tendencies are accounted for, in part, by their more favorable attitudes toward greed"
Political and social battles are often fought with words. For example, governments will use the words terrorist or freedom fighter to label groups exhibiting the exact same behaviors depending on whether we wish that group to be our allies. Piff does not define the word "greed" here. Instead it appears he wishes to use it to induce an emotional reaction: hardly the thing one would expect from a scientific study. "Greed" is a word that enters the realm of economics and is best understood from that perspective. I don't have time or space here to discuss that fully, however, in short, wealth is gained by satisfying the wants of others. In the free market, to earn wealth, you must be able to supply goods or services that others want, and do that in an efficient enough manner so that not only are your customers happy and your expenses paid (likely including the creation of jobs, improving the lives of others), but there is profit left over. Piff does not discuss this subject at all in this paper. He also does not discuss the fact that 95% of high wealth households give to charity and the income group with the largest donation rate as a percentage of income are those making 10$ million or more a year.
Piff paragraphs build up pictures of the wealthy as some kind of alien monsters: "less cognizant of others", "worse at identifying the emotions that others feel", "more disengaged during social interactions", "more likely to engage in unethical behavior", "less generous and altruistic", "more selfish" and finally concluding "These findings suggest that upper-class individuals are particularly likely to value their own welfare over the welfare of others". Aren't there other possible explanations for all this? Humans are not ant-like creatures, but individuals. Some individuals are more thinking while others are more feeling. What if being "more disengaged during social interactions" is a necessary part of being a successful business owner? If some people are wired that way and we all benefit from that persons contribution to business, is that bad? This is another example where Piff's starts from the assumption regarding some ideal human behavioral state. Regarding his mentioning that the wealthy are "less generous" I will point you to a graph below and you can make up your own mind. The differences are actually quite small.
http://nccs.urban.org/nccs/statistics/Charitable-Giving-in-America-Some-Facts-and-Figures.cfm
In the next paragraph, Piff mentions 5 more studies damning greed, which I've already discussed above. Just two points here: one, he again and again appeals to ethics, but doesn't mention any foundation of ethics. For example, what if the self interest of the wealthy leads to an overall improvement in the lives of the general population, but also an increase in inequality? Certainly Marxists and classical liberals will differ greatly on the answer to this. Piff wants to start from the assumption "self interest is bad" as FACT and build on that. But rather than being fact, it is instead a highly contentious and debatable contention.
My discussions so far are based on introductory material in this study. I have not begun to comment on the studies themselves. But, I think it's important to see that Piff's paper so far is very opinion based which leads me to believe the study is likely to find exactly what he was looking for.
In the first study, observers stood at a busy intersection and determined when drivers "cut off" other drivers and correlated that to to "vehicle status". I find numerous problems with this study: First, the study assumes that "vehicles are reliable indicators of a person's social rank and wealth". While this may be generally true, I've also found that the wealthy often don't drive high end cars and that poor do. Piff again makes sweeping assumptions about individuals. "Cut off" in this study appears to mean "did not follow right-of-way guidelines". This is certainly a judgement call to some extent. Piff mentions that the observers were "blind to the hypotheses of the study", however this could be problematic. Isn't it possible that there is a tendency for left-leaning Berkeley students to be biased here? They were "blind to the hypotheses" but then asked to tell us "when the rich people cut off other drivers". Call me suspicious, especially given Piff's other tendencies.
Piff makes a few assumptions in this study I'm not comfortable with. One is that San Francisco traffic laws represent some ideal ethical approach to driving. Is it possible that some believe in these standards more than others? To Piff this behavior is "unethical". But others might simply say it shows lack of patience. Additionally, perhaps a lack of patience correlates with other behaviors that make for successful business owners, entrepreneurs and capitalists. Piff again paints a narrow, opinion-based set of acceptable behaviors.
Another flaw that is exposed here is the tendency for Piff to take these somewhat mundane behaviors and make broad assumptions from them. Is it really true that someone who is in more of a rush at an intersection would also, for example, do nothing if they saw someone in trouble at the side of the road? PIff does not mention this nuance, and I'm left with having to think he believes this to be true.
For example, in another study, students are playing a game of monopoly. Some students are given an advantage that allows them to win. From this, Piff simply expects us to accept that the same would be true no matter how much wealth is involved or the situation over all. You can find a Ted talk video from Piff discussing the monopoly study here:
https://www.youtube.com/watch?v=bJ8Kq1wucsk
In that study, there is a point where some video of the students is shown where Piff claims the winning students are being "mean". You can find a transcript here:
http://www.ted.com/talks/paul_piff_does_money_make_you_mean/transcript?language=en
I find Piff's words and the monopoly game very difficult to reconcile. Piff finds it "rude" and apparently unacceptable that the winning students act happier, more outgoing and "eat more pretzels" than the losing players. "Rude" to Piff is making the following statements:
I have money for everything.
You owe me 24 dollars.
You're going to lose all your money soon.
I have so much money, it takes me forever.
I'm going to buy out this whole board.
You're going to run out of money soon.
I'm pretty much untouchable at this point.
Not only must we accept Piff's system of ethics, but we must also believe that a game of monopoly is predictive of more important ethical decisions. In fact, Piff makes the following statement:
"Now this game of Monopoly can be used as a metaphor for understanding society and its hierarchical structure"
I find the above statement to be, at best, ridiculous and at worst, a condemnation of Piff as a researcher in his field of study.
I have to admit, that's as far as I went in reviewing this study. Finding it flawed at nearly every turn, I do not think it worthwhile to read and comment on it fully, and this write up is getting a bit long anyway. And Frankly, I find it morally reprehensible that citizens of California and San Francisco had to pay for this.