Two studies released last week confirmed what most of us already knew: the ultra-wealthy tend to be narcissistic and have a greater sense of entitlement than the rest of us, and Congress only pays attention to their interests. Both studies are consistent with earlier research.

In the first study, published in the current Personality and Social Psychology Bulletin, Paul Piff of UC Berkeley conducted five experiments which demonstrated that “higher social class is associated with increased entitlement and narcissism.” Given the opportunity, Piff also found that they were more likely to check themselves out in a mirror than were those of lesser means.

Piff looked at how participants scored on a standard scale of “psychological entitlement,” and found that those of a high social class — based on income levels, education and occupational prestige — were more likely to say “I honestly feel I’m just more deserving than others,” while people further down the social ladder were likelier to respond, “I do not necessarily deserve special treatment.”

In an earlier study, published last year in the Proceedings of the National Academy of Sciences, Piff and four researchers from the University of Toronto conducted a series of experiments which found that “upper-class individuals behave more unethically than lower-class individuals.” This included being more likely to “display unethical decision-making,” steal, lie during a negotiation and cheat in order to win a contest.

In one telling experiment, the researchers observed a busy intersection, and found that drivers of luxury cars were more likely to cut off other drivers and less likely to stop for pedestrians crossing the street than those behind the wheels of more modest vehicles. “In our crosswalk study, none of the cars in the beater-car category drove through the crosswalk,” Piff told The New York Times. “But you see this huge boost in a driver’s likelihood to commit infractions in more expensive cars.” He added: “BMW drivers are the worst.”

Summing up previous research on the topic, Piff notes that upper-class individuals also “showed reduced sensitivity to others’ suffering” as compared with working- and middle-class people.

Lower-class individuals are more likely to spend time taking care of others, and they are more embedded in social networks that depend on mutual aid. By contrast, upper-class individuals prioritize independence from others: They are less motivated than lower-class individuals to build social relationships and instead seek to differentiate themselves from others.

These findings may appear to represent a bit of psychological trivia, but a study to be published in Political Science Quarterly by Thomas Hayes, a scholar at Trinity University, finds that U.S. senators respond almost exclusively to the interests of their wealthiest constituents – those more likely to be unethical and less sensitive to the suffering of others, according to Piff.

Hayes took data from the Annenberg Election Survey — a massive database of public opinion representing the views of 90,000 voters — and compared them with their senators’ voting records from 2001 through 2010. From 2007 through 2010, U.S. senators were somewhat responsive to the interests of the middle class, but hadn’t been for the first 6 years Hayes studied. The views of the poor didn’t factor into legislators’ voting tendencies at all.

As Eric Dolan noted for The Raw Story, “The neglect of lower income groups was a bipartisan affair. Democrats were not any more responsive to the poor than Republicans.” Hayes wrote that his analysis “suggests oligarchic tendencies in the American system, a finding echoed in other research.”

Hayes’ study is consistent with earlier research, including Princeton University scholar Larry Bartels’ 2005 study of “Economic Inequality and Political Representation.”

There are a few of ways of looking at these findings. They could be the result of genuinely held ideological beliefs which happen to justify inequality and privilege.

According to OpenSecrets, the average net worth of senators in 2011 was $11.9 million, so it could be a matter of legislators advancing their own interests and those of the people with whom they socialize and associate.

But MIT economist Daron Acemoglu, who co-authored Why Nations Fail with Harvard’s James Robinson, says that this kind of political inequality is a product of widening economic disparities. “It’s a general pattern throughout history,” he told Think Progress. “When economic inequality increases, the people who have become economically more powerful will often attempt to use that power in order to gain even more political power. And once they are able to monopolize political power, they will start using that for changing the rules in their favor. And that sort of political inequality is the real danger that’s facing the United States.”