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Midland City, Ala. showed its support for a 5-year-old boy named Ethan who was abducted from a school bus and held hostage for 6 days.Mark Wallheiser/Getty Images

The town of Midland City, Ala., is dotted with peanut farms and cotton fields -- and 2,400 people who believe in the power of prayer. 

So when a 5-year-old boy was taken hostage last week, the town held candlelit prayer vigils. And when he was rescued this week, many residents credited prayer and thanked God.

"It's by the grace of God, he's OK," Dale County Sheriff Wally Olson told AL.com.

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While scientists have tried to quantify possible effects of prayer, there are far more questions than answers. Many published studies have been discredited and refuted. The growing field of neurotheology shows some insight into the brains of people who pray, but that focuses on the effects of those who pray, not those for are prayed for.

Take the case of a Cochrane review that examined 10 studies of "intercessory prayer for the alleviation of ill health." When a biologist stumbled across it a few years after it was published, he thought the journal must have published it as a joke.

“Prayer doesn't work and cannot work. What would the mechanism of action be?” Peter Gotzsche wrote in an email to Discovery News.

Gotzsche and colleagues wrote a counterpoint to the review, concluding that the review's “mixture of theological and scientific arguments is unsound and unhelpful and would, if accepted, make all scientific endeavors meaningless. The review fails badly to live up to the high standards required for Cochrane reviews and we therefore suggest it be withdrawn.”

In a 2004 study, which was one of the 10 cited in the Cochrane review, researchers said that intercessory prayer could double the success rate of in-vitro fertilization. Controversy ensued when one of the co-authors pleaded guilty to conspiracy to commit mail and bank fraud, and the lead author took his name off the paper and resigned as chair of gynecology at Columbia University's College of Physicians and Surgeons.

In yet another large study conducted by Harvard researchers, founded by The John Templeton Foundation, no effect was found from intercessory prayer on patients recovering from heart surgery. In fact, patients who knew they were being prayed for were worse off after surgery, showing a higher rate of complications like abnormal heart rhythms. 

Neuroscientist Andrew Newberg at Thomas Jefferson University, takes a slightly different approach, scanning the brains of people who pray. His work has shown that meditation activates the front part of the brain while slowing down activity in the area of the brain "responsible for giving us a sense of our orientation in space and time." That could account for the descriptions of the effects of meditation as losing a sense of space and time. 

"The brain works in such a way that it makes religious and spiritual practices and beliefs very conducive to our way of working," he said.

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In the case of the Midland City hostage, he outlined two perspectives.

"You could make the argument in this particular case that if you have various people in the community praying, a positive attitude can result in higher likelihood of doing well," he said. "You wind up doing things beneficial to the process; it could keep negotiators calmer, people thinking clearer. You can see where that could have an impact without necessarily the divine coming into that."

Others may say that God helped more directly.

"Even if you accept that, or accept the possibility that those kind of effects can happen, there's still the question of, 'How does it happen?'" he said. "Is it that the human brain is able to some pretty amazing things, or is it actually invoking God to come down and help out? It's very hard to prove one way or another."

Most Americans, however, don't represent the general consensus among scientists: according to a 2010 USA TODAY/Gallup Poll of 1,000 adults, 92 percent say there is a God and 83 percent believe that God answers prayers.