My personal favourite definition of "intelligence," as I think the OP is using it, is "the ability to acquire and apply knowledge and skills." This presents me with a problem in averaging out the members I typically read. Some are very well-informed on many topics, others not so much so (the "acquire" part). On the other hand, some are fixated on one or more held (rather than acquired) "truths" that hamper their ability to truly apply newly acquired knowledge or skill.
You can see this mose clearly in the threads about evolution, where some members make an effort to learn the science, but fall back on "since I know God created us all, that knowledge has no meaning for me."
You see it equally clearly when a politician is quoted correctly and in context saying something that is clearly either a lie, a misdirection, or just plain evil, that is then rationlized away by those who are slavishly leashed to their own party.
And in my over 20 years here, I don't see that as improving.