I don't have a large enough sample either, but I think what you interpret as doublethink and 'Escher-painting minds' may be the result of rationalizing a faith that at its core is an emotional attachment to a cognitive error. The friend I mentioned probably doesn't have an IQ much below the median for the readers of this blog-- double major in biochem and philosophy at an ivy-league school, head of a libertarian club (would probably agree with Robin Hanson on almost everything).