Confirmation bias
Jun 8, 2011
Bishop Hill in Books, Climate: Sceptics

This is a guest post by Matt Ridley

Dan Gardner’s superb book `Future Babble’ examines why expert predictions so frequently fail, and why we believe them anyway. I strongly recommend it. Gardner devotes very little of the book to climate change, and makes clear that he does not want to be thought too sceptical about it. This is standard procedure in the world of non-fiction these days: Tim Harford in Adapt likewise avoids pursuing the logic of his argument as far into the climate debate as he might. You can, of course, kiss good bye to good reviews, or even reviews, if you stray too far from the true faith on this subject these days. Even lukewarmers like me regularly get called `deniers’.

None the less, Gardner’s argument does apply very clearly to the climate debate. Below is a list of quotations from the book that apply to pretty well any polarised scientific debate – nature versus nurture, dietary fat, and of course scepticism versus alarm. Honest readers will admit that they fall into all the traps Gardner describes, whether they are sceptics or alarmists. (At the end of the lists are a few quotes, about the value of doubt, that will be more uncomfortable for the alarmists.)

Here is my question: can we each read these quotes and admit that they apply to each of us as well as to the people we disagree with? It’s a question for sceptics and alarmists alike. Or does each of us think we are more self-aware about confirmation bias than our opponents are?

Here are the quotes:

Once we form a belief, for any reason, good or bad, rational or bonkers, we will eagerly seek out information that supports it, while not bothering to look for information that doesn’t – and if we are unavoidably confronted with information that does not fit, we will be hyper-critical of it, looking for any excuse to dismiss it as worthless. P84

We all enjoy having our beliefs confirmed after all. And it shows that we too are informed people. But dispute that belief and the same psychology works against you. You are risking saying goodbye to your client and your reputation. Following the herd is usually the safer bet. P 109.

Contrarians ... are almost always outsiders, which is not a coincidence. They don’t have a seat at the table so they aren’t subject to the social pressures identified by Asch and other psychologists. P 109.

Genuinely imaginary attempts to portray change – including scenario planning – may help pull us out of that rut but they may also cause to us to develop an unrealistic sense of how likely those imaginative futures really are. And all the while, no matter what happens, we are convinced we are right. P 115

Having settled on a belief, we naturally subject evidence that contradicts the belief to harsh critical scrutiny or ignore such evidence altogether. At the same time we lower our standards when we examine supportive evidence so that even weak evidence is accepted as powerful proof. P 204.

It should be obvious that being skeptical about a prediction does not render people unable to make a decision, it just makes them cautious. This is not a bad thing, and, indeed, in some circumstances, it can be a very good thing. P 247

Doubt is the hallmark of the fox. P 254 [foxes, who are open to wider sources of evidence, are more accurate forecasters than hedgehogs, who adhere to one big idea.]

"Foxes"’... are modest about their ability forecast the future, comfortable with uncertainty, and very self-critical. P 255.

(Buy at Amazon.co.uk, Amazon.com)

Article originally appeared on (http://www.bishop-hill.net/).
See website for complete article licensing information.