That psychological effect you're talking about, where conflicting information just makes you put your head in the sand, is a pretty common one. Public Radio this morning had a segment on people who continue to take echinacea to stop colds, despite evidence that it doesn't work any more than jumping jacks do.
People just have their little pattern of thinking, and can't bear to reorient it without a really good reason. Apparently, "a really good reason" does not mean "scientific studies say so," or anyway not at first. There's some sort of critical word-of-mouth mass before people will trust science.
My thinking on intelligent design is that it is a way of saying that science is not allowed to have unresolved questions. Whereas, the coolest scientific leaps happen when people start theorizing into the void! That is why science works -- it grows and changes its pattern of thinking (sometimes reluctantly).
Saying "the underpants gnomes did it" is not thinking; it is saying that thinking is useless. People who truly believe that thinking is useless should be required to surrender their brains forthwith. I stand a-ready with the chain saw.