If I’m serious about keeping my New Year’s resolutions in 2009, should I add another one? Should the to-do list include, “Start going to church”?

This is an awkward question for a heathen to contemplate, but I felt obliged to raise it with Michael McCullough after reading his report in the upcoming issue of the Psychological Bulletin. He and a fellow psychologist at the University of Miami, Brian Willoughby, have reviewed eight decades of research and concluded that religious belief and piety promote self-control.

This sounded to me uncomfortably similar to the conclusion of the nuns who taught me in grade school, but Dr. McCullough has no evangelical motives. He confesses to not being much of a devotee himself. “When it comes to religion,” he said, “professionally, I’m a fan, but personally, I don’t get down on the field much.”

His professional interest arose from a desire to understand why religion evolved and why it seems to help so many people. Researchers around the world have repeatedly found that devoutly religious people tend to do better in school, live longer, have more satisfying marriages and be generally happier.

These results have been ascribed to the rules imposed on believers and to the social support they receive from fellow worshipers, but these external factors didn’t account for all the benefits. In the new paper, the Miami psychologists surveyed the literature to test the proposition that religion gives people internal strength.

“We simply asked if there was good evidence that people who are more religious have more self-control,” Dr. McCullough. “For a long time it wasn’t cool for social scientists to study religion, but some researchers were quietly chugging along for decades. When you add it all up, it turns out there are remarkably consistent findings that religiosity correlates with higher self-control.”

As early as the 1920s, researchers found that students who spent more time in Sunday school did better at laboratory tests measuring their self-discipline. Subsequent studies showed that religiously devout children were rated relatively low in impulsiveness by both parents and teachers, and that religiosity repeatedly correlated with higher self-control among adults. Devout people were found to be more likely than others to wear seat belts, go to the dentist and take vitamins.

But which came first, the religious devotion or the self-control? It takes self-discipline to sit through Sunday school or services at a temple or mosque, so people who start out with low self-control are presumably less likely to keep attending. But even after taking that self-selection bias into account, Dr. McCullough said there is still reason to believe that religion has a strong influence.

“Brain-scan studies have shown that when people pray or meditate, there’s a lot of activity in two parts of brain that are important for self-regulation and control of attention and emotion,” he said. “The rituals that religions have been encouraging for thousands of years seem to be a kind of anaerobic workout for self-control.”

In a study published by the University of Maryland in 2003, students who were subliminally exposed to religious words (like God, prayer or bible) were slower to recognize words associated with temptations (like drugs or premarital sex). Conversely, when they were primed with the temptation words, they were quicker to recognize the religious words.

“It looks as if people come to associate religion with tamping down these temptations,” Dr. McCullough said. “When temptations cross their minds in daily life, they quickly use religion to dispel them from their minds.”

In one personality study, strongly religious people were compared with people who subscribed to more general spiritual notions, like the idea that their lives were “directed by a spiritual force greater than any human being” or that they felt “a spiritual connection to other people.” The religious people scored relatively high in conscientiousness and self-control, whereas the spiritual people tended to score relatively low.

“Thinking about the oneness of humanity and the unity of nature doesn’t seem to be related to self-control,” Dr. McCullough said. “The self-control effect seems to come from being engaged in religious institutions and behaviors.”

Does this mean that nonbelievers like me should start going to church? Even if you don’t believe in a supernatural god, you could try improving your self-control by at least going along with the rituals of organized religion.

But that probably wouldn’t work either, Dr. McCullough told me, because personality studies have identified a difference between true believers and others who attend services for extrinsic reasons, like wanting to impress people or make social connections. The intrinsically religious people have higher self-control, but the extrinsically religious do not.

So what’s a heathen to do in 2009? Dr. McCullough’s advice is to try replicating some of the religious mechanisms that seem to improve self-control, like private meditation or public involvement with an organization that has strong ideals.

Religious people, he said, are self-controlled not simply because they fear God’s wrath, but because they’ve absorbed the ideals of their religion into their own system of values, and have thereby given their personal goals an aura of sacredness. He suggested that nonbelievers try a secular version of that strategy.

“People can have sacred values that aren’t religious values,” he said. “Self-reliance might be a sacred value to you that’s relevant to saving money. Concern for others might be a sacred value that’s relevant to taking time to do volunteer work. You can spend time thinking about what values are sacred to you and making New Year’s resolutions that are consistent with them.”

Of course, it requires some self-control to carry out that exercise — and maybe more effort than it takes to go to church.

“Sacred values come prefabricated for religious believers,” Dr. McCullough said. “The belief that God has preferences for how you behave and the goals you set for yourself has to be the granddaddy of all psychological devices for encouraging people to follow through with their goals. That may help to explain why belief in God has been so persistent through the ages.”