Signalling, selfishness, and altruism

Some argue that people aren’t really altruistic, and that all purportedly altruistic behaviour can, in the final analysis, be wholly explained by self-interested preferences. On this analysis, people help others in order to send positive signals about themselves.

But this raises the question why helping someone sends a positive signal to third parties. If people aren’t into altruism, why do third parties care?

One explanation could be that third parties are signalling to each other. Suppose that you help someone, and that one third party gives you reputational points for that. It may be that they do that in order to send a positive signal about themselves to other third parties.

But that still raises the question why that is a positive signal, in the eyes of the other third parties. So in order to get this chain of signalling going, you need to assume that people have some intrinsic preference for altruistic behaviour.