At last, an explanation for Wall Street's disgrace, Bernard Madoff's Ponzi scheme and other high-society crimes and misdemeanors:  A  new study published in the Proceedings of that National Academy of Sciences found that wealthier people  were more apt to behave  unethically than those who had less money.

Scientists at  the University of California at Berkeley analyzed a person's rank in society (measured by wealth, occupational prestige and education) and found that those who were richer were more likely to cheat, lie and break the law than those who were poorer.

"We found that it is much more prevalent for people in the higher ranks of society to see  greed and self-interest … as  good pursuits," said Paul Piff, lead author of the study and a doctoral candidate at Berkeley. "This resonates with a lot of current events these days."

In the first of  two studies, researchers found that those who drove more expensive cars (an admittedly questionable indicator of economic worth) were more likely to cut off other cars and pedestrians at a busy San Francisco four-way intersection than those who drove older, less-expensive vehicles.

In other experiments,  wealthier study participants were more likely to admit they would behave unethically in a variety of situations and lie during negotiations. In another, researchers found wealthier people were more likely to cheat in an online game to win a $50 prize.

Greed is a "robust" determinant of unethical behavior, according to the study.

"This has some pretty clear implications," said Piff. "Inequality is very much on Americans' minds, and the potential effects of severe inequality on individual levels of behavior are major."

Large sums of money may give people greater feelings of entitlement, causing those people to be the most averse to wealth distribution, Piff continued.  Poorer people may be less likely to cheat, because they are more dependent on their community at large, he said. In other words, they don't want to rock the boat.

"People in power who are more inclined to behave unethically in the service of gains and self-interest can have great effects on society as a whole," said Piff.

And it's difficult to say whether richer people get to the top because of their unethical behavior or whether wealth causes people to become this way. "It seems like a vicious cycle," he said.

Nevertheless, Piff said these results obviously don't apply to all wealthy people. He noted that Bill Gates and Warren Buffett were among the wealthiest people in the world and also the most philanthropic. He also pointed to high rates of violent crime in the poorest neighborhoods in the country that counteract the study's findings.

Piff said he hoped to further his research by figuring out ways to curb these patterns of behavior among wealthier individuals.

"What it comes down to, really, is that money creates more of a self-focus, which may account for larger feelings of entitlement," said Piff.  "We hope to further study how we can curb these patterns and how that will affect our social environment."