What makes animals act altruistically- benefiting another animal at personal cost? Biologists talk about kin selection for close relatives (“Would I lay down my life to save my brother? No, but I would to save two brothers or eight cousins,”) or for social animals like bees or naked mole rats (who are extra closely related through special reproductive castes or inbreeding) and reciprocal altruism for unrelated (or only distantly related) animals. Reciprocal altruism is Tit-for-Tat: I help you this time, and you help me next time. If you don’t help me next time, I notice, and stop cooperating with you.
The classic example is vampire bats: mother bats will share regurgitated blood with their babies, of course, but an adult bat that comes back to the roost without a blood meal can also get blood from one of his roostmates who was more successful that night. In fact, “donor bats” will often offer blood (rather than first being solicited), particularly when they frequently interact socially with another bat through grooming, and in exchange the next time around, when the other guy has a luckier night on the cattle range, he’ll share with you.
Of course, sometimes you want more reciprocal altruism, and sometimes you want less. If we don’t want another kind of bloodsuckers to value their “donors” over their constituents, it seems there are a few ways of going about it- making it harder for donors to give, making it harder for politicians to reciprocate, making it harder for politicians to engage in “social grooming” with donors outside of check-writing time. One could argue that frequent and competitive elections might allow for reciprocity between voters and politicians to develop, but I’m pretty sure we’re the cattle in this analogy, not the bats.