I tried to tell my daughter a joke

I wanted to see how much abstract thought my daughter could hold in her head at once. She likes to laugh, and when she laughs at movies, it's mostly appropriate.  Sometimes, it's not. Sometimes, the theater is silent. Sometimes, the audience is busy being horrified by what they saw. Whereupon Nat breaks out in loud boisterous laughter.

I wondered, does she laugh because she understands something is funny, or is it a canned response that she pulls up when she's looking for a way to respond to her environment?

So I told her a joke, and watched her reaction. This is the joke I told:

Someone with autism goes in to see the doctor. The doctor looks over the charts and says, "Your short term memory is getting worse and you still have problems understanding abstract expression." The  person looks at the doctor and says, "Well, at least my short term memory isn't getting worse."

She listened to the joke, stared at me blankly, then said, "Can I go play on the iPad?"

I think I'll try a different joke.