Political scientists widely accept that individuals have no tangible, rational reason to vote. If the decision was made from a pure rational choice perspective, we'd all stay home. A rational choice voting model looks like this:
V = PB – C
V is your net benefit from voting, and you only vote if V > 0. P is the probability of your vote deciding the election, while B is the value of your expected difference between the parties (i.e., if you are a fervent Democrat and loathe the Republicans, B is large). C is the costs of voting – time, information, attention, and so on. Here's the rub: in any reasonably sized electorate, P asymptotically approaches zero. The P*B term, for all intents and purposes, is zero (something like 0.0000000000000001). Since C > 0 (voting is never without some costs) a rational person would never vote.
But people do vote, even though the rational choice model makes sense. This is what political scientists call "the Paradox of Voting." No one should vote, yet lots of people do. The answer lies in Riker and Ordeshook (1968), who revise the model thusly:
V = PB – C + D
It's the same model, of course, with an additional term representing the "expressive" benefits of voting. In other words, you vote because it makes you feel better. D represents a sense of civic duty, the warm and fuzzy feeling you get from supporting someone you like, or the psychological conviction that your vote is helping determine the outcome. D also represents, among more sophisticated voters, an understanding of the free rider dilemma. That is, you recognize that if everyone approached the decision rationally and stayed home, turnout would be zero and therefore one or two individuals could decide the whole election. Translation: you realize that if everyone else is being rational and staying home, it is rational for you to be irrational and vote.
Tuesday was primary day in Indiana, and I did not vote. My "D" term is negative. Not only do I not get a jolly feeling from voting, I actually feel sick when I do it. Psychologically, voting implies that I think this process has any legitimacy or that I accept it as valid. Neither of those things are true. There's an anecdote attributed to the Roman Emperor Hadrian, who was stopped by a poor woman while traveling through the city with his entourage. He told the woman "I don't have time for your problems," to which she replied "Then you have ceased to be Emperor."** I guess you could say all of these people have ceased to be my emperors.
The phrase "rational non-voting" always cracks me up. All non-voting in the American context is rational. Hell, unless you really get a kick out of it, staying home is far more rational than voting. Given the paucity of parties, the universally unappealing candidates, and the oppressive, naked media editorializing which hammers viewers with the reality that Big Money and Big Media and Serious Experts have already decided the outcome, it's a miracle that anyone shows up.
**Suitably chastised, he stopped to talk with her.