Why should you vote?

In a typical election with a greater-than-one vote differential, it doesn't seem like your vote matters at all to the outcome. In the specific sense that if you had not voted, the outcome would have been identical. So I guess that is something to resolve, do you deserve fractional "credit" for the win, even if the win differential was by millions of votes?

Having large numbers of people at polling places at election time is a show of trust and civic participation.

I suspect that the opposite is true. It seems to me that people would be less likely to vote if they trust their fellow citizens to make the right choice and believe that the political system is fine. Turnout was at its highest in 40 years in 2008, in spite of the fact that most people agree there was a profound amount of political distrust and acrimony in that election.

To make things worse, if there's a multiverse, if you're correlated with some people in the same universe as you then you're also correlated with a humongous number of people in different universes (far more humongous than the number of actual copies of you).

To my mind this is the most compelling reason to vote. If you're rational and you want more rational people to vote, then you should vote, because then they will too (assuming a reasonable number of rational people have similar relevant information to your own).

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.

In my post I suggested there are two separate motivations for voting:

1) Picking the winner. Essentially no one does this in big elections, but yes there is that tiny chance. I didn't go into this motivation. Thinking about it now I suspect using a lottery-like mentality a lot of people do vote for this reason: they just might be the one.

2) Adding to voter turnout, thus making the election legitimate. Everyone who votes does this, but it's only by a tiny amount. This I would equate to "not littering" in that you are unambiguously helping but only incrementally. This I think is in fact the stronger reason for voting, but still your contribution is very tiny.

In the end I'm down to "civic duty" and "it's the right thing to do" and stuff like that as far as the best reason to vote. Maybe the lesson is it's good large chunk of people are NOT rational, because I do maintain as turnout goes down, the results get worse, as far as what people "really" want.

Now I didn't mention social pressure either. There was a swiss study where voter turnout didn't go up when vote-by-mail was made an option. The supposition being people no longer felt the pressure to make an appearance at the polls to be a good citizen, they could just surreptitiously not vote in the privacy of their own home.

http://www.mitpressjournals.org/doi/abs/10.1162/jeea_a_00015?journalCode=jeea

I think you are right that good feelings and status are a big part of it. Why do people endure all manor of inconvenience to be a part of any big event, a movie opening or concert or rally? A lot of bragging rights to have been a part of something, rather than just watched it on TV.

Still I wonder if that is the whole explanation. The system needs X% of voters out there to be viable, but it has no real carrot to attract people to vote. So then voters just assign a value to voting, and show up in relatively large numbers on their own. And it all works out? It's a very clever arrangement if that's how it works.