Well this is interesting. A new paper in a forthcoming issue of the Journal of Experimental Social Psychology presents evidence that prayer can increase a person's ability to resists temptation--and offers a non-supernatural explanation for the phenomenon:
The authors made use of two experimental paradigms to test the efficacy of prayer in preventing cognitive depletion. The first, called an emotion-suppression task, simply asked participants to watch a funny video but stifle all emotional responses, verbal and non-verbal, to the content. This requires a good amount of cognitive energy to pull off successfully. The second, called a stroop task, asked participants to indicate the ink color of various words flashed to them on a computer screen. The trick is that the words spell the names of various colors that are either consistent or inconsistent with the ink they are to identify. Check it out here. You’ll find that the inconsistent word/ink items are harder to respond to than the consistent items. Researchers have found that after cognitive depletion, this task becomes even harder. So, the authors had an elegant methodological question: will people who pray be able to avoid the depleting effects of emotion suppression and not show a deficit on the stroop task? In other words, will prayer give them the cognitive strength to perform well on both these challenging tasks?
Indeed it did. Participants who were asked to pray about a topic of their choosing for five minutes showed significantly better performance on the stroop task after emotion suppression, compared to participants who were simply asked to think about a topic of their choosing. And this effect held regardless of whether participants identified as religious (70 percent) or not.
Why? The authors tested several possible explanations, but found statistical support for only one: people interpret prayer as a social interaction with God, and social interactions are what give us the cognitive resources necessary to avoid temptation. Past research has found that even brief social interactions with others can promote cognitive functioning, and the same seems to hold true for brief social interactions with deities.Read it all here.