Schjødt, of the University of Aarhus, Denmark, and colleagues, asked volunteers to carry out two tasks involving both religious and "secular" activities. In the first task, they silently recited the Lord's Prayer, then a nursery rhyme. Identical brain areas, typically associated with rehearsal and repetition, were activated.
In the second, they improvised personal prayers before making requests to Santa Claus. Improvised prayers triggered patterns that match those seen when people communicate with each other, and activated circuitry that is linked with the theory of mind - an awareness that other individuals have their own independent motivations and intentions (Social Cognitive and Affective Neuroscience, DOI: 10.1093/scan/nsn050).
Two of the activated regions are thought to process desire and consider how another individual - in this case God - might react. Also activated were part of the prefrontal cortex linked to the consideration of another person's intentions, and an area thought to help access memories of previous encounters with that person.
The prefrontal cortex is key to theory of mind. Crucially, this area was inactive during the Santa Claus task, suggesting volunteers viewed Santa as fictitious but God as a real individual.
Previous studies have found that the prefrontal cortex is not activated when people interact with inanimate objects, such as a computer game. "The brain doesn't activate these areas because they don't expect reciprocity, nor find it necessary to think about the computer's intentions," says Schjødt.
He says the results show people believe they are talking to someone when they pray, an outcome that pleased both atheists and Christians: "Atheists said it shows that it's all an illusion," says Schjødt, while Christians said it was evidence that God is real.
Brain scans reveal that people believe they are talking to someone when they pray
Robin Dunbar at the University of Oxford points out that the study proves neither: "This has nothing to do with whether God exists or not, only with subjects' beliefs about whether God exists."