Said-Bookisms, Emotion, and Children

I bought Alex a couple of new books on Saturday, and we've been reading them over and over, the way he normally does the first few days after getting something new. One thing I noticed is how much the characters' emotions are described with said-bookisms and adverbs, things that are generally frowned upon in adult fiction. For young readers, I think it does make sense to use them, since they aren't experienced in picking up subtle clues about emotions. So, when do kids learn how to interpret body language and facial expressions in fiction? Does it depend on how much they read? Does there ever come a point where kids/readers in general start to notice said-bookisms, or is that a writer thing? Do any readers of this blog have answers for me?