So far DS seems to not have the kind of personality that makes for a show-off. He is very at ease with himself, and also just incredibly innocent. He has no idea that it's odd to be able to read like he does.

I used to worry about DD, but she seems to have gone the other direction and talks herself down instead (other side of the same coin, though, in a way--but I think she only does this with us; around others she seems just fine, really).