Willard wrote:
That's why they call it a Spectrum - there's a lot of difference between Low Functioning Autism and High Functioning Autism.
Just as there's a lot of difference between what someone with Asperger Syndrome or High Functioning Autism is like when they're a child, and what they're like when they become an adult. Some things that are baffling to us at 4 years old, we have all figured out by the time we're 20 or 30.
I don't know if babies on the low functioning end of the spectrum usually comprehend peek-a-boo or not. If not, it's probably got something to do with the Theory of Mind issues. The whole point of the game is that the baby realizes that the person hiding behind their hands didn't really go anywhere and that it's just a silly pretense.
If you didn't understand that, and thought the person actually disappeared when you couldn't see them, then I suppose you wouldn't laugh. You might even get upset that they left, even though they didn't.
I think the whole point of the game is that they don't understand the person is still there, but as they keep playing it and growing older, they figure it out. When they first start, they are surprised when the person pops out, but when they get older they giggle.