Cognitive Dissonance, Democracy, And Informed Consent
All of this is true, of course. But what is the alternative? If cognitive dissonance theory undermines the validity of democracy as a means of governance, surely it undermines the alternatives as well. A dictator is probably even more likely to suffer from this problem -- his ego alone would not allow an admission of being wrong -- than the average voter.
The human brain is all we have to work with, I'm afraid. Its weaknesses and disturbing tendencies certainly do undermine our ability to rule ourselves in a coherent and rational manner, but even more do they undermine our claim to rule others.
Ed's correct to some degree, but two thoughts come to mind in response. First, the persistent findings of voter irrationality do more violence to representative democracy than to some other forms of government. Democratic governments derive their authority from the consent of the governed as granted through the act of voting; an unstated corollary is that, ideally at least, voting should be a rational activity. On the other hand tyranny, to take Ed's example, makes no claims to rationality or informed consent; the tyrant generally establishes power purely through force or threat thereof. As far as theoretical grounding goes tyranny actually comes out ahead since it doesn't assume that voters are rational.
The other thought is that, in practice, irrationality doesn't make that big a difference. Voters in the US are generally called upon to pick the Republican or the Democrat, either one of which will generally support some policies that are sound and some policies which are unsound. Rational evaluation of candidates is of limited value when there are only ever two parties to choose from. This suggests to me that, if we recognize that voters are ignorant, we should seek to design our electoral system in such a fashion as to minimize the impact of that irrationality.
One tack we could take is to try to reduce the sources of misinformation which cause people to take up irrational positions in the first place. What motivates oh... say... Glenn Beck to just make up shit left and right? And what causes people to trust Glenn Beck in the first place even after it's amply demonstrated that he's wrong more often than he's right? I don't have much in the way of answers to either of those questions, but my gut tells me that demonization of the kind in which Glenn Beck engages is most effective in a polarized environment. Polarization, in turn, stems in large part from there being only two practical choices at any given time.
An alternate tack is to isolate the voter from needing to have informed opinions on specific issues. Economists can't agree amongst themselves as to whether we should trim the budget or engage in deficit spending, so it seems foolish to build a system that expect voters to evaluate the issue. They're much more qualified to express support for the broad principles that turn up in party platforms and such.
In either case it would be beneficial to move away from the personality-centered, two party system that we currently have to a party-centered system with proportional representation. This would allow more diversity of opinion, (hopefully) reducing polarization and the crazy that comes with it. At the same time, by focusing on parties rather that individuals, it allows voters to think more about principles rather than any one person's specific promises or policies.
On a more cynical note, however, all of the above discussion assumes that its possible to rationally evaluate candidates (or parties) in the first place. But when the "good guys" renege on campaign promises and are basically indistinguishable from the "bad guys" its questionable whether democracy is meaningful at all anymore. Sure, we can throw the bums out in four years, but it seems like our only choice is to replace them with another set of bums who will make a lot of promises which come to naught.