"Now researchers believe they know what’s responsible for the bulk of the rise: Nothing. Much of the rise in autism is likely a statistical mirage."

I've kind of always thought this, ever since I read a tumblr post about how the sudden change in toddlers would have been called "my child being switched with a changeling", and other such tales.

Also, I think most of pre-industrial life would have been more bearable for autistic people: No sudden noises like ambulance sirens, solid routine and repetitive jobs, not as many large crowds.