Adam wasn't created dumb. We are not progressing from dumb to intelligence like evolution thinks.
Consider this, Adam was created with the ability to talk. He even knew he had bones.
Absolutely.
If we are a fallen race, and our DNA is becoming more and more corrupted with time (and there does seem to be evidence of this) then it is extremely easy to imagine that ancient people had superior intellects.
As Tommy pointed out, intellect and knowledge are not the same.
We certainly have more knowledge now, more data.
But they probably had a superior raw intellect.
Even if you just go back a few hundreds years you'll find great Bible scholars doing extraordinary works and commentaries with very few resources. How exactly do you write an entire Bible commentary without having even a rudimentary concordance, or engage in sophisticated writing and editing with just an ink quill and no computer? Simple: you must have vast amounts of scripture memorized, and you have to write brilliantly, with fully organized ideas flowing straight out of your mind, with very little editing.
Even if we just go back a few hundred years we see people doing things we can scarcely imagine.
I'm sure the ancients were brilliant.
Well, at least some of them, lol.