One wonders how it manifested itself before ships were invented, or in the ancestral hunter-gatherer environment. Surely there must have been autistic nomads.
"Look, he said he knows where all the fruit bearing trees in this forest are. Not a lot of them, all of them. He pointed out a squirrel the other day and told it he was glad to see that it made it through the winter. I don't know how he does it, but if he says we have to move because the squirrels are starting to move to new trees, who am I to argue? We move."