Brains

Articles like this are always a fun read. This blurb reminds me of a book chapter that discusses a cult whose members only proselytize even more passionately after their doomsday prediction failed to come true (and they had already discarded all of their worldly possessions).

Classic research has suggested that the more people doubt their own beliefs the more, paradoxically, they are inclined to proselytize in favor of them. David Gal and Derek Rucker published a study in Psychological Science in which they presented some research subjects with evidence that undermined their core convictions. The subjects who were forced to confront the counterevidence went on to more forcefully advocate their original beliefs, thus confirming the earlier findings.

[NYT]