I disagree with the notion that any concept can be conveyed regardless of IQ. I saw the example first hand last night.
My mother is quite and intelligent lady, I reckon her IQ is quite high average (around 110/120) but she didnt understand the fundamental concept that I am open to new ideas and will try a few things that she would never do. She also couldn't grasp that me buying a ballgag and some nipple clamps on ebay does not make me a whore.
I suppose it goes back to the old nature or nurture thing as to whether someone can be taught a concept regardless of IQ. Do we learn from our surroundings and experiences or is it pre-programmed genetically? I agree with Ghostie's theory that the "dumbing down" of a concept can make the original concept fundamentaly flawed as important chunks of the original concept may be lost in translation. This is something that we can see in translations of literature where one language has a particular word which means something to them but the word chosen for translation has different conotations for us.