Not to jump to someone else's defense, but it is not a matter of brains or intelligence, or the combination of using both. It is more a matter of volume of material, learning theory has something called interference, which we see a lot in beginning students, and it is always a challenge to gauge the level of the class and teach just a little more than they can absorb.
They can see how to get there, but if I executed my techniques or forms at speed, I get the most amazing "huh" looks from my students, including Brown Belts. They see it, but cannot figure out how to get there. There are many levels of learning the same thing, and I think it is not a matter of withholding anything. My biggest criticism of myself is I let my own enthusiasm overwhelm my students with the subtlies of any given technique, when maybe I should teach a base which you can test with, then add to it as they can. But always keep the material available for those who are ready to add another level of sophistication to their movement, or application of any given technique or form.
Does this make any sense at all? It definitly applies to Short Form #1 as I teach it to kids or beginners, and what I expect of my more advance belts. They do essentially the same thing .... the difference is in how they do it.
-Michael
