Off the top of my head, it seems like “foot in the door” factors could support the OP’s thesis (people are more likely to go along with larger requests after already doing smaller ones for the same person/cause, apparently related to cognitive dissonance reduction). Moral licensing effects would seem to go the other way. It would be interesting to hear from an expert in the social sciences which effect tends to be stronger.
Off the top of my head, it seems like “foot in the door” factors could support the OP’s thesis (people are more likely to go along with larger requests after already doing smaller ones for the same person/cause, apparently related to cognitive dissonance reduction). Moral licensing effects would seem to go the other way. It would be interesting to hear from an expert in the social sciences which effect tends to be stronger.