Ward wrote:

>Actually, I would be interested if you know of any mainstream psychological
>works or theories on the subject of extremism, just to see what "the
>conventional wisdom" is supposed to be.

Ward, try doing a literature/net search on "cognitive dissonance."
Dissonance theory isn't tightly linked to extremism but it does try to
account for the persistence of beliefs in the face of strong contrary
evidence.

David