When some religiously devout people hear a charismatic healer speak the word of god , the regions of their brains involved in skeptical thinking and vigilance appear to shut down. Uffe Schjødt of Aarhus University in Denmark and his colleagues scanned the brains of Pentecostalists while they listened to recorded prayers from non-Christians, "ordinary" Christians, and a healer. The brain activity changed only in response to prayers they were told came from the healer. According to Schjødt, the same deactivation may occur in response to the words of physicians, parents, politicians, and other charismatic leaders. The researchers published their results in the journal Social Cognitive and Affective Neuroscience.
From New Scientist:
Parts of the prefrontal and anterior cingulate cortices, which play key roles in vigilance and scepticism when judging the truth and importance of what people say, were deactivated when the subjects listened to a supposed healer. Activity diminished to a lesser extent when the speaker was supposedly a normal Christian.
Schjødt says that this explains why certain individuals can gain influence over others, and concludes that their ability to do so depends heavily on preconceived notions of their authority and trustworthiness.