I think Atheists generally tend to consider Christians dumb for their beliefs. And their IQs may actually be higher than the thiests on average.
I believe you are correct... Yesterday I was going to make that statement about intelligence... but thought it might be perceived as inappropriate.
I think highly intelligent people... tend to have a more difficult time with matters of spirituality... I am thinking of the Sheldon-type of people... the ones who are all math and science... It's a blanket statement... however... I have seen people of superior intelligence grapple with Christian concepts that I have simply accepted without the need of "proof".
I also agree with your assessment of knowledge not being equivalent to wisdom... The two are distinctly different.
However... God seems to have a way of touching the hardest of hearts.