The paper reports the results of seven separate studies. The first four include surveys of Boston rail commuters, UChicago undergraduate students and a nationally representative database of online respondents in the United States. In these surveys, participants reported their own belief about an issue, their estimated God's belief, along with a variety of others, including Microsoft founder Bill Gates, Major League Baseball's Barry Bonds, President George W. Bush, and an average American.
Two other studies directly manipulated people's own beliefs and found that inferences about God's beliefs tracked their own beliefs. Study participants were asked, for example, to write and deliver a speech that supported or opposed the death penalty in front of a video camera. Their beliefs were surveyed both before and after the speech.
The final study involved functional magnetic resonance imaging to measure the neural activity of test subjects as they reasoned about their own beliefs versus those of God or another person. The data demonstrated that reasoning about God's beliefs activated many of the same regions that become active when people reasoned about their own beliefs.
The researchers noted that people often set their moral compasses according to what they presume to be God's standards. "The central feature of a compass, however, is that it points north no matter what direction a person is facing," they conclude. "This research suggests that, unlike an actual compass, inferences about God's beliefs may instead point people further in whatever direction they are already facing."
Citation: Nicholas Epley, Benjamin A. Converse, Alexa Delbosc, George A. Monteleone John T. Cacioppo, 'Believers' estimates of God's beliefs are more egocentric than estimates of other people's beliefs', 2009, Proceedings of the National Academy of Sciences