Taken together, the neurological states evoked by the questions are known to cognitive scientists as the Theory of Mind: They underlie our understanding that other people have minds, thoughts and feelings.
The advantages of a Theory of Mind are clear. People who lack one are considered developmentally challenged, even disabled. Anthropologist Scott Atran, a proponent of the byproduct hypothesis, has suggested that it let our ancestors quickly distinguish between friends and enemies. And once humans were able to imagine someone who wasn't physically present, supernatural beliefs soon followed.
But just as a Theory of Mind provided benefits, so might its supernatural byproducts and the religions that grew from them.
Unlike other animals, humans can imagine the future, including their own death. The hope given by religious beliefs to people confronting their own mortality might provide motivation to care for their offspring.
Supernatural beliefs may also have produced group-level advantages that then conferred benefits to individuals.
"You get some selective advantages, such as inter-group cooperation and self-policing morality," said Barrett. "And maybe the entire network of belief practices, and whatever is behind them, gets reinforced."
According to Barrett, religion may even have created a feedback loop, refining the Theory of Mind that produced it.
"It could be that when you're in a religious community, it improves what psychologists call perspective-taking," he said. "Exercising your Theory of Mind could be good for developing it, making your reasoning more robust."
The human capability to develop Theory of Mind is one of the more interesting abilities, along with the mental Time Machine, which allows us to imagine sequences of events that have not happened, or which might happen in the past. Supposedly, it's impossible or very difficult to estimate how we will feel about something at a future time (e.g., what would you like for breakfast on this day next year); we end up thinking of how we feel at the present time (what you actually like for breakfast now), rather doing the timeshift first and comparing the difference.