The possibility of autistic traits in prehistoric societies offers all sorts of interesting avenues for speculation. One of my favourites is the connection with gluten. A lot of the behaviours associated with the autistic continuum are (in a subset of people) ameliorated to some extent if gluten is removed from the diet.
This makes me wonder how the introduction of gluten-rich wheat products may have caused an increased incidence of autistic traits in early farming societies, resulting in changes in those societies at the point in time when agriculture first really got underway. Changes that may have manifested themselves by leaving traces of an increased preoccupation with repetetive, predictable events*, as repetition and predictability are two of the most common features of autistic behaviour patterns.
*perhaps in the form of big rocks placed to mark solstices and equinoxes etc.
