The myth of the rational voter
Posted November 10, 2008
on:I wish I had time at the moment to read Bryan Caplan’s new book or the piece he has written at Cato unbound on the myth of the rational voter. Having only done the briefest skim I can’t really comment on the conclusions he reaches. However, the title seams fairly self explanatory.
This has really made me think of all the people I saw interviewed during the election night coverage saying they used to vote Labour but had decided to vote for National because it was “time for a change”. When pressed why change was needed not one person had anything to say. I kept joking at the time that it was the “obama factor” (where in my opinion change was needed). In hindsight I’m concerned that it was. I can’t help but find it slightly worrying that people voted National but didn’t really have a reason to other then “change”.
Agnitio: Happy National are in but worried about how they got there…..
16 Responses to "The myth of the rational voter"

I agree there is rationality in the ‘time for a change concept’. There is a tendency for Governments to become arrogant in the new zealand context, which I believe was the underlying feature of the current Labour Government. This was reflected in the ministerial working party which aimed to reduce Government expenditure, but then determined all of its expenditure was appropriate.


As I understand it, utility maximisation is a way of modelling people’s decisions – but few economists would say people literally make their decisions by weighing up a series of mathematical equations.
The corollary to this is: that people can’t articulate reasons behind their decisions doesn’t mean those decisions aren’t rational.
The problem that Caplan points out is that people are not just ignorant of their reasons, they are actively irrational.
What I find surprising about his proposed solutions is that he advocates more reliance on free markets. Surely if people are irrational in politics, they are irrational in markets too? Isn’t irrationality an issue across all spheres, and therefore not a good distinguishing feature of any one?


Rachel, you’ve not read Caplan carefully enough. In his model, people are rationally irrational: in low consequence, low cost environments (like voting), they’ll indulge their preferences over beliefs; in high consequence environments (like markets), they think a little harder about things. You may well retort that voting is a high consequence environment; in the aggregate that’s true, but each voter’s probability of decisiveness is low enough that he doesn’t worry much about it. Classic externality story, really.
Caplan’s stuff figures prominently in the last couple of weeks of the public choice class I teach at Canterbury…he was on my dissertation committee….


Kimble is right. People dislike Labour because of a combination of lots of little things, not any one big things. To name just a couple of little things would seem like a poor reason to change the government so people said ‘change’ instead. But the real reasons are there.


Every voter is irrational because the probability of there single vote making a difference means its not worth voting. Therefore how can we trust anyone to vote rationally, when the mere decision to vote is irrational?
I saw a recent web video about an economist who refuses to vote because everyone else votes and therefore its not worth it. It was rather interesting but I can’t remember the link.
Its even worse under MMP because your vote is swallowed by all votes, whereas under FPP your vote is only shared with your electorate (though I suppose its prob actually similar given the probability your vote makes a difference in your electorate and whether your MP makes a difference to the government)


lets assume it is rational, what about the people that don’t vote?
I think a good model is that those who choose not to vote don’t get enough “warm fuzzies” or to make enough of a difference, whereas those who do vote, do get enough enjoyment from it. As this number increases the difference for the marginal voter decreases, and eventually we have an equilibrium.
Maybe this explains the lower voter turnout in America because it is watered down by the larger population.


Steve, the economist you’re thinking of is the Econo-God Gordon Tullock. I tell my students that he sits at the head of the Pantheon of the Econ-Gods, hurling thunderbolts at all those who displease him.
Voting is irrational if it is an instrumental act. If it’s consumption rather than investment, well, economists have little to say about onanism.
Steve and Agnito: both of you should check out both Caplan’s Myth and Brennan & Lomasky’s prior Democracy and Decision, which lays out the expressive voting argument.

November 10, 2008 at 3:57 pm
I think it is much more likely that people did think it was time for a change but for a wide variety of reasons that are difficult for an individual to list off the top of their head.
For example, the general arrogance that defined Labours final term may have finally gotten to people, but few would be able to specify a specific incident on which their decision hinged.