> Interesting -- could it be because they missed the age at which
> mathematical instruction should start, somewhat like the case of
> foreign languages, which get harder to learn as one leaves childhood?
> Or would a different method from the one these anthropologists used get
> better results? (They were not math teachers after all; perhaps
> professional remedial math teachers would have been more suited to the
> task.)
Wish I knew; I'm sure I'll speak about it with my educational psychologist friend next time we meet. The results were quite conclusive though: none of the students could get to 1+1=2 reliably.
John