One particularly fertile subfield in Economics is Public Choice Theory. This applies the analytical tools of economics to the questions raised by political scientists. The framework that emerges as a result sheds light on the expected behavior of public officials.
Economists work from the working assumption that people wish inter alia, to maximize their income and minimize their efforts. This leads to the Paradox of Voting. The Paradox simply is that given the assumption stated above, economists cannot explain why people choose to vote.
The argument runs as follows: in any election where more than a handful of people vote, the probability that the margin of victory is going to be 1 is diminishingly small. Most elections would be expected to be won with margins in at least the thousands. In the 2000 US presidential elections, Bush won Florida with a margin of 537. In the 2004 US elections, the closest margin of victory was in Wisconsin, where Kerry won by just over 11,000 votes. Suppose now that you were a Florida voter in 2000 supporting Kerry. If you voted, you merely decreased the margin of victory from 538 to 537, compared with what it would be if you had not voted. If you didn’t vote, you merely increased the margin of victory from 536 to 537. On the other hand, suppose you were a Bush supporter. If you voted, you increased the margin of victory from 536 to 537. If you didn’t vote, you decreased the margin of victory from 538 to 537. These differences simply don’t matter: in the closest election in recent memory, there still was no mathematical justification for going to the polls. The numbers simply don’t add up.
Non-economists typically get riled, even offended by these sorts of arguments. The typical response is: 'That’s silly. What if everyone started thinking like that? Then if no one went, my vote would matter.' This is correct, but irrelevant. If you were the only voter in the country, your vote would matter. But then everyone else will reason the same way and show up on Election Day, and then yet again, your vote will not change the outcome.
At this stage, I hope to have convinced you of an interim claim: that your decision to vote or not will not have a substantial influence on whether your candidate wins or not. You don't have to agree that your vote doesn't matter in a larger sense, merely that the probability of you being pivotal to an election outcome is much less than your probability of being struck by lightning (and don't worry, that probability is minute also).
Now it is easy to see why your trip to the polling booth flummoxes economists: they assume that people are driven to behave according to perceptions of benefits and costs. The tangible benefits of voting are probabilistically nonexistent. The costs however can be relatively substantial: you have to give up a nice evening relaxing at home to go to the polling booth and stand in lines. Your costs outstrip your tangible benefits so greatly in fact, that through economists' lenses, voting is as absurd as setting fire to dollar bills and flushing the ashes down the toilet.
Despite occasional claims to the contrary, economists really aren't omniscient however. They have had to acknowledge that people show up to vote around the world, but that they don’t burn money. Faced with this paradox, economists have had to relax their assumptions about human behavior. They have had to admit that humans sometimes work for the collective good, or what they think is the right thing to do. However, since we still don’t have a good analytical framework for predicting charitable behavior, the explanations for voting presented by economists so far are mostly speculative.
A word of clarification then: this article is meant to describe the analytical paradox that arises through a particular framework of thinking. Until social scientists have a clearer grasp of human motivation and the robustness of social institutions, we really can't move from trying to understand and describe this aspect of human behavior, to prescribing preferred ways of behaving.
As our American readers gear up to vote this year, perhaps some of you can leave comments describing why you vote?