# Ben Franklin effect: mkay, what about help vampires?

Is the Ben Franklin effect as uncontroversial as wikipedia makes it to be? It states that once we grant someone a favor we're even more inclined to grant them subsequent favors. As far as I can tell from Wikipedia the effect was experimentally tested (under rigorous conditions) maybe 3 times. If the effect always holds, how comes we (eventually) dislike help vampires? Is there a liking curve that goes up and then down with the number of favors?