Last month, Red Nose Day, a biennial charity extravaganza, managed to break its fundraising record despite the recession. But to what extent are charities recession-proof? Much depends on what motivates us to give, a subject that has been receiving a lot of attention from economists recently.

There are many possible motivations. One is pure altruism: we give to charity because we care about the well-being of others. A second infamous motivation for giving was advanced by the economist James Andreoni: the “warm glow”. Warm-glow givers donate money to charity because it makes them feel good.