Somewhere in the last year I read an article (not sure if it was on the mudcat) that thought fingerpicking was an outgrowth of the picking of the multi-stringed harps found in West Africa (can't remember their name). Apparently players of those instruments use techniques of alternating thumb bass against melody picked on the treble strings with forefinger. I believe there was also a tie in of the diaspora of those Africans to the American Piedmont area (probably through slavery )where our guitar fingerpicking seems to have the oldest roots.