I think one of the arguments declaring that voting is rational is a bit suspect.

But here's the good news. If your vote is decisive, it will make a difference for 300 million people!

In the rather unlikely event that your vote decisive, this is true enough (for US voters anyway). The error he makes though is the assumption that your decisive vote will always create a positive change. If you're going to take the credit for the right decisive vote, you have to take the blame for the wrong decisive vote.

Some people might go on to argue that it's the voters job to make an informed choice, but good luck with that. Even the most informed voter is going to be working with sketchy information, politicians don't always (ever?) deliver everything they promise.

Worse still, you can't even tell what positive/negative real life events were actually dependent on who is in office even in theory, let alone in practice.

I'm not going to say whether voting behaviour is rational or not because I'm not sure everyone is using the same definition as me, but I will say that I think people seriously overestimate the power of their vote.

Thanks for the links. They seem to mostly be saying: the "pay off" for being the swing vote is gigantic, changing everyone's life, so even though the chance of being that vote is infinitesimal it's rational to go for the tiny chance of making a huge difference.

I'm sure this is valid reasoning, but it's disappointing to me if this is the whole story. It's like voting as lottery, that your vote essentially never matters except when it has this giant impact.

I think there is mapping problem here as well. Just as you can't map your vote onto one of the excess votes in a normal election, you can't map your vote onto that one winning vote in a close election. In each case it's a game of probabilities and fractional contributions only. But I can't sort it all out.