normally the smarter someone is the easier they are to fool, because they have trusted authority all of their lives, and generally have more of a stake in society - the conequences of their whole career's being a sham is too much for most people to contemplate.

normally every one has the same reaction when you tell them they're not on a spinning ball flying through outer space, just like their own senses tell them they're not.
simple brainwashing.