Many Americans doubt the morality of atheists. According to a 2007 Gallup poll, a majority of Americans say that they would not vote for an otherwise qualified atheist as president, meaning a nonbeliever would have a harder time getting elected than a Muslim, a homosexual, or a Jew. Many would go further and agree with conservative commentator Laura Schlessinger that morality requires a belief in God—otherwise, all we have is our selfish desires. In The Ten Commandments, she approvingly quotes Dostoyevsky: "Where there is no God, all is permitted." The opposing view, held by a small minority of secularists, such as Richard Dawkins, Daniel Dennett, Sam Harris, and Christopher Hitchens, is that belief in God makes us worse. As Hitchens puts it, "Religion poisons everything."
Arguments about the merits of religions are often battled out with reference to history, by comparing the sins of theists and atheists. (I see your Crusades and raise you Stalin!) But a more promising approach is to look at empirical research that directly addresses the effects of religion on how people behave.
In a review published in Science last month, psychologists Ara Norenzayan and Azim Shariff discuss several experiments that lean pro-Schlessinger. In one of their own studies, they primed half the participants with a spirituality-themed word jumble (including the words divine and God) and gave the other half the same task with nonspiritual words. Then, they gave all the participants $10 each and told them that they could either keep it or share their cash reward with another (anonymous) subject. Ultimately, the spiritual-jumble group parted with more than twice as much money as the control. Norenzayan and Shariff suggest that this lopsided outcome is the result of an evolutionary imperative to care about one's reputation. If you think about God, you believe someone is watching. This argument is bolstered by other research that they review showing that people are more generous and less likely to cheat when others are around. More surprisingly, people also behave better when exposed to posters with eyes on them.
Maybe, then, religious people are nicer because they believe that they are never alone. If so, you would expect to find the positive influence of religion outside the laboratory. And, indeed, there is evidence within the United States for a correlation between religion and what might broadly be called "niceness." In Gross National Happiness, Arthur Brooks notes that atheists are less charitable than their God-fearing counterparts: They donate less blood, for example, and are less likely to offer change to homeless people on the street. Since giving to charity makes one happy, Brooks speculates that this could be one reason why atheists are so miserable. In a 2004 study, twice as many religious people say that they are very happy with their lives, while the secular are twice as likely to say that they feel like failures.
Since the United States is more religious than other Western countries, this research suggests that Fox talk-show host Sean Hannity was on to something when he asserted that the United States is "the greatest, best country God has ever given man on the face of the Earth." In general, you might expect people in less God-fearing countries to be a lot less kind to one another than Americans are.
It is at this point that the "We need God to be good" case falls apart. Countries worthy of consideration aren't those like North Korea and China, where religion is savagely repressed, but those in which people freely choose atheism. In his new book, Society Without God, Phil Zuckerman looks at the Danes and the Swedes—probably the most godless people on Earth. They don't go to church or pray in the privacy of their own homes; they don't believe in God or heaven or hell. But, by any reasonable standard, they're nice to one another. They have a famously expansive welfare and health care service. They have a strong commitment to social equality. And—even without belief in a God looming over them—they murder and rape one another significantly less frequently than Americans do.
Denmark and Sweden aren't exceptions. A 2005 study by Gregory Paul looking at 18 democracies found that the more atheist societies tended to have relatively low murder and suicide rates and relatively low incidence of abortion and teen pregnancy.