The results showed that when people were primed to think about religion and God, either consciously or unconsciously, brain activity decreases in areas consistent with the anterior cingulate cortex (ACC). The ACC is associated with a number of things, including regulating bodily states of arousal and alerting us when things are going wrong.
Interestingly, atheists reacted differently. When they were unconsciously primed with God-related ideas, their ACC increased its activity. The researchers suggest that for religious people, thinking about God may provide a way of ordering the world and explaining apparently random events and thus reduce their feelings of distress.
In contrast, for atheists, thoughts of God may contradict the meaning systems they embrace and thus cause them more distress.