Why do people vote?

The most important concept in political economy is the median voter: the person giving the majority to a proposal or a political candidate. Given that the likelihood for anyone to be the median voter is very slim, and that voting involves some cost, it is a mystery why so many people vote.

The easy answer is that people have been drilled to perform their civic duty and vote. Thus, they just do it. Andrew Gelman and Noah Kaplan have a better answer: people do not vote just for themselves, they also proxy for the others. Therefore, the return of a vote becomes much larger: Even if the likelihood of being the median voter is small, the return in that event is not just the personal return, but it is multiplied by the number of people benefiting. In other words, voters do not only look for private returns but also for social returns.

There is plenty of evidence of such altruistic behavior in voting. For example, people do not vote selfishly on many referenda. When a proposal for a swimming pool passes a vote, do you really think more than half the voters would actually use it? When the electorate approves of the use of medical marijuana, despite the fact that only a minority will ever benefit of it, it is not thinking selfishly. When an all-male electorate gives the right to vote to women, it is clearly not just looking for its own gain. Imagine that, electorates sometimes even approve tax increases...