Money and helpful conduct

Maybe they should and maybe they shouldn't (be paying them). Peter Singer is exploring the idea that money - money just as such, even the very awareness of it - may alter people's behaviour for the worse. He cites an experiment in which a group made conscious in trivial ways of the existence of money tended to behave less cooperatively and helpfully than another group not so prompted. Singer also cites Marx's view on the alienating effects of money (something which I've blogged about previously): the way money gives individuals powers they would not otherwise possess and instrumentalizes human relationships. Marx's thinking about the subject is, I continue to think, illuminating. But I must say I have my doubts about the experiment Singer discusses. I'm not in any position to question its methods in detail on the basis only of what he reports. My doubts arise, however, from the hunch that there are likely to be countervailing facts about typical individual conduct as influenced by money, and I'm wondering - assuming that hunch is right - whether the experiment accommodates these.

It's a pure guess, but imagine that the many charities that collect money from people were to forego it henceforth and ask all their donors, instead of giving money as before, to come out in person and 'donate' by making a personal effort of one kind or another. Assuming one could measure the 'before' and the 'after' on a common scale, would charitable (let's still call it) giving increase or decrease? I'm guessing the latter.