By Ian Hodder, Special to MSN

Wouldn't you know it? Turns out the politician who brags about his unimpeachable ethics isn't exactly squeaky-clean behind the scenes, and the starlet who tsk-tsks about bimbo culture is quick to pose half-naked in a magazine. With so many public figures, from Eliot Spitzer to Rush Limbaugh, behaving in opposition to their stated virtues, hypocrisy is always making headlines.

The latest hypocrite on the public stage: John Edwards.

Or is he?

Not according to psychologists. Hypocrisy adds a moral twist to plain-old lying, cheating or self-deception. "It's only hypocritical when you oppose the behavior publicly," says James M. Olson, a social psychologist at the University of Western Ontario. By that measure, Edwards doesn't meet the bar.

Compare, for example, the indiscretions of Edwards and Eliot Spitzer. Infidelity allegations against Edwards started bubbling in the tabloid press in fall 2007, and though he denied the rumors, he didn't campaign against adultery or criticize unfaithful husbands. So when Edwards recently confessed to an extramarital affair, he outed himself as a liar and a cheater.

New York Gov. Spitzer, however, was revealed as a hypocrite when he resigned amid allegations he had patronized a call girl. He ran for office promising high ethics, and as state attorney general had busted up prostitution rings. Prosecuting hookers while patronizing them: That's hypocritical.

At hypocrisy's root

Before you climb up on your moral high horse, know that everyone is sometimes a bit hypocritical. We've all behaved in ways that are inconsistent with our beliefs or attitudes. Perhaps you pretend to agree with your boss's politics or, conveniently ignoring your own teen years, tell your kids never to smoke pot. Such minor lapses can be automatic, psychologists say.

"We couldn't possibly make a deliberate decision about every one of our actions, so it's not surprising that occasionally we do something hypocritical," says Olson. "Hypocrisy is surprising when it involves a fundamental value or something that's publicly important."

Conservative Idaho Sen. Larry Craig, for example, shocked his constituents and colleagues in 2007 when police in Minneapolis arrested him in a sex-solicitation sting in a men's restroom. (Craig pleaded guilty to disorderly conduct.) An attempted same-sex hookup, under icky circumstances no less, contradicted the public's expectations for a married senator opposed to gay rights.

Broadly speaking, hypocritical behavior stems from two human desires: to present a good self-image and to judge other people. "People care about what people think of them," explains University of Regina philosopher Eldon Soifer, coauthor of Hypocrisy: Ethical Investigations. So we alter ourselves to fit into society, with manners and clothing for example. Hypocrisy arises when we take such social conventions too far and mask our true selves. "When someone misleads us about that," Soifer says, "we think his moral character is out of whack."

Hypocrisy in politics & life

Exploitation of the discrepancy between a person's public and true selves is a standard tool in modern political debate. In most elections, different candidates support different platforms, and all the debate in the world is not going to convince politicians to concede that their principles are inferior. As a result, they charge the opposition with hypocrisy.

"It's become a way of supporting your argument, in a strange sort of way," Soifer says. Being branded a flip-flopper or campaigning for something you previously opposed can be politically worse than stubbornly sticking to a bad idea. "People think that whatever your principles are, you should believe in them."

But, warns Boston College political scientist Alan Wolfe, the electorate's obsession on rooting out hypocrisy is a distraction: "As political sins go, it's not that awful." Not to mention, Wolfe adds, hypocrisy does not necessarily indicate poor governing skills.

"There have been hypocritical people who were great leaders, and there have been sincere people who were terrible leaders," he says. He cites Franklin Delano Roosevelt, who was less than forthright about his plans to enter World War II, as an example of the former. On the other hand, "President Bush was not hypocritical in leading us into war in Iraq, but that's turned out to be a disaster."

Sullied role models

Public figures are prone to hypocrisy because societal and other standards (a political party's platform, for example) dictate how they should behave, whether they agree with those principles or not. Also, politicians and pastors are routinely asked to make moral statements, and because they're in the public eye the stakes of behavioral discrepancies are greater, as are the chances of getting caught.

We feel personally invested in famous people and, therefore, personally betrayed when they violate our standards. Which brings us to this collection of famous hypocrites, ranging from the aforementioned Spitzer to disgraced athletes and self-deluded actors. Notice how strident many of these celebrities were in pointing out bad behavior in others. "In many cases," Soifer notes, "someone who is vocally critical of others is concealing something about himself."

So is there a cure for hypocrisy? "You can't simply resolve to stop judging others or to stop being a hypocrite," writes University of Virginia psychologist Jonathan Haidt in The Happiness Hypothesis. But, Haidt says, we can train our brains to take a more philosophic approach to life (he recommends meditation and cognitive therapy). "Finding fault with yourself is also the key to overcoming the hypocrisy and judgmentalism that damage so many valuable relationships."

See the slide show "The Hypocrisy Hall of Shame."

Vote: Who doesn't belong on the list? Who is the biggest hypocrite?

Ian Hodder is a freelance writer living in Brooklyn, N.Y.