It's strange, because I talk to these people. By that I mean, I'll ask a Family Guy fan a question, and he will respond in a manner that pertains to the question. So I know these folks are smart enough to have learned the language of their own mothers.
I have also seen them react to stimuli, that is, turn their heads in the direction of a screeching car nearby, or blink when a light is shone in their faces. It could be logically assumed that if I threw a bowling ball at a Family Guy fan, he would have enough intelligence to duck.
But then I realize that these "people" think that the mere mention of Qubert is funny in and of itself, and I know that I must be hallucinating about the aforementioned abilities.