Both my boys, 3 and 5, have had amazing ability to focus on tasks interesting to them. At school they are the kids that sit quietly and listen. Their focus is one of the things about their giftedness I appreciate the most.
I agree 100% with AvoCado. I was in denial myself with DS5. Kept questioning myself thinking I was over thinking etc. Once tested it was clear that the signs were there from a very early age. It was so nice to finally "know" my boy on all levels. Get an understanding for why he did things the way he did.
Of course, now I am in the same boat with DS3. Questioning myself, being in denial. My younger is so different though it makes me pretty sure he is a visual-spatial learner. So if having this other puzzling child isn't confusing enough, I can't even compare him to my older since he is not following the same track...
