Haven't read the article yet, and I'm not certain what you mean by the "doctrine of affect" - but if you're referring to the explanation, you will hear Cape Breton fiddlers say that they're 'keeping the time' with their foot-tapping - most of the notable CB fiddlers are not, in my experience, nearly as articulate as David Greenberg when it comes to elucidating the fine points of their craft, but if pressed, I would expect that they would agree that he had it right. I would suggest that the loud, steady beat of the foot also helps the dancers stay with the beat while the fiddler is pushing it or dragging it with the instrument.