What types are most likely to be found laughing at everything during a conversation, whether it's really funny or not?
I'm remembering back to a time when I was in college, and I was standing in line for something. In the line next to me, this guy was talking with this girl (I don't know if they already knew each other or if they just happened to meet there in line), and every other thing he or the girl said, this guy would laugh hysterically. A very annoying laugh, too. I was not close enough to hear what the girl was saying, but the guy was loud and clear and he wasn't really saying anything funny, yet he kept laughing.
Is this Fe-DS? My LSI brother does this sort of thing occasionally, too (though not nearly to the same extent as in the example above).