Who is happier about life — liberals or conservatives? The answer might seem straightforward. After all, there is an entire academic literature in the social sciences dedicated to showing conservatives as naturally authoritarian, dogmatic, intolerant of ambiguity, fearful of threat and loss, low in self-esteem and uncomfortable with complex modes of thinking. And it was the candidate Barack Obama in 2008 who infamously labeled blue-collar voters “bitter,” as they “cling to guns or religion.” Obviously, liberals must be happier, right?

Wrong. Scholars on both the left and right have studied this question extensively, and have reached a consensus that it is conservatives who possess the happiness edge. Many data sets show this. For example, the Pew Research Center in 2006 reported that conservative Republicans were 68 percent more likely than liberal Democrats to say they were “very happy” about their lives. This pattern has persisted for decades. The question isn’t whether this is true, but why.

Many conservatives favor an explanation focusing on lifestyle differences, such as marriage and faith. They note that most conservatives are married; most liberals are not. (The percentages are 53 percent to 33 percent, according to my calculations using data from the 2004 General Social Survey, and almost none of the gap is due to the fact that liberals tend to be younger than conservatives.) Marriage and happiness go together. If two people are demographically the same but one is married and the other is not, the married person will be 18 percentage points more likely to say he or she is very happy than the unmarried person.

"If two people are demographically the same but one is married and the other is not, the married person will be 18 percentage points more likely to say he or she is very happy than the unmarried person." -- Arthur Brooks

The story on religion is much the same. According to the Social Capital Community Benchmark Survey, conservatives who practice a faith outnumber religious liberals in America nearly four to one. And the link to happiness? You guessed it. Religious participants are nearly twice as likely to say they are very happy about their lives as are secularists (43 percent to 23 percent). The differences don’t depend on education, race, sex or age; the happiness difference exists even when you account for income.

Whether religion and marriage should make people happy is a question you have to answer for yourself. But consider this: Fifty-two percent of married, religious, politically conservative people (with kids) are very happy — versus only 14 percent of single, secular, liberal people without kids.

An explanation for the happiness gap more congenial to liberals is that conservatives are simply inattentive to the misery of others. If they recognized the injustice in the world, they wouldn’t be so cheerful. In the words of Jaime Napier and John Jost, New York University psychologists, in the journal Psychological Science, “Liberals may be less happy than conservatives because they are less ideologically prepared to rationalize (or explain away) the degree of inequality in society.” The academic parlance for this is “system justification.”

The data show that conservatives do indeed see the free enterprise system in a sunnier light than liberals do, believing in each American’s ability to get ahead on the basis of achievement. Liberals are more likely to see people as victims of circumstance and oppression, and doubt whether individuals can climb without governmental help. My own analysis using 2005 survey data from Syracuse University shows that about 90 percent of conservatives agree that “While people may begin with different opportunities, hard work and perseverance can usually overcome those disadvantages.” Liberals — even upper-income liberals — are a third less likely to say this.

So conservatives are ignorant, and ignorance is bliss, right? Not so fast, according to a study from the University of Florida psychologists Barry Schlenker and John Chambers and the University of Toronto psychologist Bonnie Le in the Journal of Research in Personality. These scholars note that liberals define fairness and an improved society in terms of greater economic equality. Liberals then condemn the happiness of conservatives, because conservatives are relatively untroubled by a problem that, it turns out, their political counterparts defined.

Imagine the opposite. Say liberals were the happy ones. Conservatives might charge that it is only because liberals are unperturbed by the social welfare state’s monstrous threat to economic liberty. Liberals would justifiably dismiss this argument as solipsistic and silly.

There is one other noteworthy political happiness gap that has gotten less scholarly attention than conservatives versus liberals: moderates versus extremists.

Political moderates must be happier than extremists, it always seemed to me. After all, extremists actually advertise their misery with strident bumper stickers that say things like, “If you’re not outraged, you’re not paying attention!”

But it turns out that’s wrong. People at the extremes are happier than political moderates. Correcting for income, education, age, race, family situation and religion, the happiest Americans are those who say they are either “extremely conservative” (48 percent very happy) or “extremely liberal” (35 percent). Everyone else is less happy, with the nadir at dead-center “moderate” (26 percent).

What explains this odd pattern? One possibility is that extremists have the whole world figured out, and sorted into good guys and bad guys. They have the security of knowing what’s wrong, and whom to fight. They are the happy warriors.

Whatever the explanation, the implications are striking. The Occupy Wall Street protesters may have looked like a miserable mess. In truth, they were probably happier than the moderates making fun of them from the offices above. And none, it seems, are happier than the Tea Partiers, many of whom cling to guns and faith with great tenacity. Which some moderately liberal readers of this newspaper might find quite depressing.

Arthur C. Brooks is the president of the American Enterprise Institute and the author of “The Road to Freedom” and “Gross National Happiness.”