Is Pluto a planet? The world's astronomers met in Prague last week to vote on this question, and in a sort of cosmic game of "Survivor," they voted Pluto off the solar system.

In 1935, researchers from Columbia University fanned out around the city of Allentown, Pa., and handed out leaflets ahead of local and state elections. What residents did not know was that they were part of an experiment in political persuasion -- an experiment whose results came to mind last week...

When freedom fighters in India inspired by Mahatma Gandhi turned violent in a clash with police in 1922, the nonviolent leader took personal responsibility, called off nationwide protests and starved himself for five days in a penitential fast. Gandhi was nearly alone in thinking an apology of such...

Here's a question with three different answers. The first answer is derived from arithmetic. The second comes from common sense. The third is based on psychology.

When the Rev. Martin Luther King Jr. called on America to open the doors of opportunity to people of color, the civil rights leader was making a moral argument.

When George W. Bush takes the podium tomorrow night to deliver his sixth State of the Union address, what are the chances he will say this? "The war in Iraq has been one gigantic mistake. I am sorry I got us into this mess. I am going to bring the troops home right away."

The 58 fans sitting before the big-screen television were watching the Super Bowl. Psychologist Emily Pronin was watching the fans.

The perjury trial of I. Lewis "Scooter" Libby goes to the jury this week. The case speaks to several issues -- how the Bush administration deals with critics of the war in Iraq, and the games that Washington's reporters and politicians play with each other. As far as the jury is concerned, however,...

If Democrats Hillary Clinton and Barack Obama ever took a break from fundraising to bone up on psychology, they might realize the need to talk up . . . John Edwards.

Like most people in Virginia, Donald Black was horrified by Seung Hui Cho's shooting rampage last week that left 33 people dead, including the shooter.

The ambitious immigration overhaul package that Congress is studying has drawn criticism from conservatives who say it offers amnesty to lawbreakers, and from immigration advocates who say it will not do enough to bring millions of people out of the shadows.

This year's National Basketball Association playoffs recently provided not one but two examples of a very interesting facet of human decision making. Even if you are not a sports fan, these moments tell you something about human nature.

There are two ways to think about the staggering amounts of money given by special interest groups to politicians -- the type of contributions that were detailed for the last quarter in reports filed yesterday by presidential candidates and members of Congress.

In the face of mounting public and political opposition to the war in Iraq, recent reports from the White House suggest that President Bush remains serenely confident.

Long before word recently broke that white referees in the National Basketball Association were calling fouls at a higher rate on black athletes than on white athletes, and long before studies found racial disparities in how black and white applicants get called for job interviews, researchers no...

As big Labor Day sales roll around, computer stores will tell you about laptops that now come with biometric fingerprint readers. Car companies will talk about "variable air suspension" features that allow you to change the ride of a car, depending on terrain. And video game manufacturers will ha...

John Duffy lost 67 of his colleagues at the firm of Keefe, Bruyette & Woods six years ago during the Sept. 11, 2001, terrorist attacks. Among the dead was Duffy's son Christopher. The investment banking firm, located in the South Tower of the World Trade Center, was among the companies hit hardes...

Four years ago, during a speech in Manila, President Bush drew an analogy between the history of the Philippines and the history he was rewriting in Iraq.

Shortly after the Sept. 11, 2001, attacks, psychologist Jennifer Lerner conducted a national field experiment: She asked a random sampling of Americans how likely it was that they would be the victim of a terrorist attack in the next 12 months.

In the courts and in Congress, Sen. Larry Craig is fighting to withdraw his guilty plea to a misdemeanor charge that may suggest he tried to solicit sex from a man in June at a Minneapolis airport bathroom. Rather than resign yesterday, as the senator had promised and Republicans had hoped, Craig...

If you were Barack Obama, you would be scratching your head, too.

Let's say there are 10 houses on your street and a giant pothole develops right in the middle of the block. Everyone benefits if the pothole gets fixed, but that might require multiple calls to municipal authorities and a lot of hassle. Since every resident benefits even if he or she does nothing...

With just over five minutes to play in yesterday's game against the New York Jets, the Washington Redskins found themselves on their own 23-yard line facing a fourth and one. The team, which was ahead by just three points, elected to do what teams normally do in such situations: They played it safe...

If you consult the online encyclopedia Wikipedia, which is democratically created by Internet users, you will see a pattern emerge in the phrases used to describe the first female leaders of many countries.

In the interest of promoting democracy, Pakistan's president, Gen. Pervez Musharraf, recently announced that he had to lock up most of his country's democracy activists. And because he wanted the Pakistani Supreme Court to independently rule on whether he could continue as president, Musharraf also...

Social psychologist William B. Swann once had a group of married people evaluate their spouses even as their spouses evaluated them. People with high self-esteem, the psychologist found, felt closer to their partners when they received positive evaluations. People with low self-esteem, however, felt...

Scrooge crept towards it, trembling as he went; and following the finger, read upon the stone of the neglected grave his own name, Ebenezer Scrooge . . . "Spirit!" he cried, tight clutching at its robe, "hear me! I am not the man I was. I will not be the man I must have been . . . "

Two sociologists and a mathematician recently conducted an experiment that provides an intriguing window into the presidential candidate selection that begins this week. Matthew Salganik, Duncan Watts and Peter Sheridan Dodds had a large group of people rate 48 songs. Based on these ratings, the...

According to conventional wisdom, front-runners win presidential nominations. Democrats and Republicans who start the race for a presidential nomination with the largest amount of money and the best poll numbers are supposed to be the ones most likely to walk away with victory months later.

Some years ago, a political scientist conducted an interesting experiment that speaks to the fractured race for the Republican presidential nomination, which now has six candidates, five issues, and four potential front-runners.

Mitt Romney wants to round up 12 million illegal immigrants and deport them. John Edwards wants to put an end to lobbyists. All the Democratic and Republican presidential candidates rail against the ways of Washington.

What do you think is more dangerous? Terrorists getting their hands on a biological weapon that can be smuggled into the country or another hurricane like Katrina? Which is the smarter way to keep Social Security solvent? Raise the retirement age or raise taxes? How can the current economic crisi...

If you happen to stop by a Victoria's Secret store this Wednesday evening, on the eve of Valentine's Day, you will learn something fascinating about human nature that will tell you a lot about people and relationships.

John McCain once called televangelists Pat Robertson and Jerry Falwell "agents of intolerance," but now the Republican senator from Arizona is currying favor with social conservatives. Sen. Hillary Rodham Clinton (D-N.Y.) now opposes the Iraq war, although she used to support it. Sen. Barack Obama...

Climate change. Pollution. Financial expense. Our gas-guzzling ways have long been associated with a variety of problems, but disturbing evidence now points to a new dimension of our love affair with petroleum: Oil consumption and high oil prices hurt the political, social and economic development...

In Eliot Spitzer's sex scandal and tragicomic downfall, the question that bugged many people did not have to do with ethics or politics, but whether Spitzer got a raw deal.

About 25 years ago, Cass Sunstein opened a retirement account that had two portfolios. One was mostly bonds, the other mostly stocks. Like many academics who use the TIAA-CREF investment program, Sunstein divided his money equally between stocks and bonds.

If this were Britain, Russia or India, Rudy Giuliani '08 caps would not be on the clearance racks. In those countries, where bigwigs and insiders get to nominate party leaders, the former Republican front-runner and establishment favorite would have long ago been anointed the winner.

Tell all the Truth but tell it slant/Success in Circuit lies/Too bright for our infirm Delight/The Truth's superb surprise . . .

The housing market is in free fall: Quick -- let's protect homeowners against foreclosure.

The United States is awash in gloom. Overwhelming majorities of Americans say they are dissatisfied with the country's economic direction, and the intensity of unhappiness is greater than it has been in 15 years, according to a recent Washington Post-ABC News poll. The answer, pundits, politicians...

Subprime mortgages have been linked to a meltdown in housing and questionable Wall Street practices, and they may have been the original domino that set off America's current economic crisis.

In May, the baby-faced chief executive of IndyMac Bancorp, Michael Perry, lashed out at critics who said the bank was on weak footing: "Given the decline in our stock price, some people have questioned IndyMac's survivability in the current environment. I am here to tell you that I believe we hav...

Consider these scenarios. Scandal A: A prominent politician gets caught sleeping with a campaign aide and plunges himself into an ugly paternity dispute -- all while his cancer-stricken wife is fighting for her life.

Political conventions, like all forms of public relations, carry the risk of whiplash. Last week in Denver, for example, Bill Clinton said Barack Obama "has a remarkable ability to inspire people, to raise our hopes and rally us to high purpose" -- all of which sounded a little different from the...

In the days after the attacks of Sept. 11, 2001, with the twin towers vanished from Manhattan's skyline, a poem by W.H. Auden could have been the song of a wounded nation. "September 1, 1939," written on the eve of World War II, seemed eerily prescient:

Have you seen the photo of Republican vice presidential nominee Sarah Palin brandishing a rifle while wearing a U.S. flag bikini? Have you read the e-mail saying Democratic presidential nominee Barack Obama was sworn into the U.S. Senate with his hand placed on the Koran? Both are fabricated -- and...

A few years ago, psychologists Mahzarin Banaji and Thierry Devos showed the names of a number of celebrities to a group of volunteers and asked them to classify the well-known personalities as American or non-American. The list included television personality Connie Chung and tennis star Michael ...

After nearly two years of political jockeying for the presidency, hundreds of millions of dollars of advertising and wall-to-wall campaign coverage in the media, nearly half of all Americans eligible to cast ballots in the presidential election may not bother to vote. Turnout for primaries, as well...

The Center for Responsive Politics recently estimated that it cost $5.8 billion to finance the 2008 general elections. To most people that is a staggeringly large sum and evidence of the profoundly corrupting role that money plays in politics, but to some very smart political watchers, the better...