One thing that has often irked me is the criticism politicians get for making U-turns. What’s wrong with changing your mind if new information comes to light?
A new paper by Armin Falk and Florian Zimmermann of the University of Bonn sheds light on my puzzlement. People, they say, value consistency in themselves and in others as a way of signalling intellectual strength.
And this value is an intrinsic one. We don’t just like consistency because it is a means to better decision-making. We value it even if it gets in the way of rational decisions.
Falk and Zimmermann established this experimentally. They got subjects to estimate the number of peas in a bowl. Subjects were first asked to make an estimate. They were then told that the wisdom of crowds means that average estimates are often more accurate than individual estimates, and told what the average estimate was. Subjects were then invited to give a second estimate of the number of peas, being paid according to the accuracy of that estimate.
They found that subjects did not update their first estimates by very much in light of that new information. As a result, they ended up making more inaccurate estimates, on average, than people who had merely been given information about the average estimate and then invited to make an estimate without having made an earlier guess.
A desire for consistency, they conclude:
induces subjects to act consistently at the cost of neglecting valuable information and receiving lower payoffs…Early statements on a matter can make people ignore valuable information.
This is consistent (!) with a classic study (pdf) by Lee Ross and colleagues back in 1979. They found that when supporters and opponents of the death penalty were given the same evidence to consider - some it of supportive of the penalty and some not - their beliefs became more polarized. This contradicts Bayes’ theorem, but is consistent with people wanting to behave consistently, wanting to maintain their pre-established position.
There are three aspects of Falk and Zimmermann’s experiment that are especially significant:
1. There was no ambiguous information that might have been interpreted to corroborate subjects initial estimates. In the real world however - as in Ross’s experiment - there is often such noisy information. This means the desire for consistency will, in practice,often be reinforced by the confirmation bias, our tendency to interpret new data in a way that corroborates our priors.
2. The number of peas in a bowl is a simple factual matter. An opinion on it is therefore not constitutive of our identity in the way that our political opinions are. It should, therefore, be susceptible to change in the face of new evidence. That even such “neutral” opinions can be easily fixed means we should be especially pessimistic about the prospects for changing other opinions.
3. Subjects in this experiment had little concern with a reputation for consistency. Politicians, however, want to establish such a reputation. This will strengthen the desire for consistency.
The message here is a depressing one - it’s that rational cool-headed political dialogue is very difficult, simply because once we have taken a position, evidence does not shake it.