Overcoming confirmation bias


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We often wrangle over the nature of scientific evidence here at Sweat Science, so Jonah Lehrer’s recent blog post on the “argumentative theory” should be of interest to many readers. It’s a new explanation for why humans are so prone to confirmation bias — our habit of seeking out evidence that confirms our expectations and ignoring evidence that contradicts them:

In essence, [researchers Hugo Mercier and Dan Sperber] argue that human reason has nothing to do with finding the truth, or locating the best alternative. Instead, it’s all about being able to argue with others.

Here’s how Mercier explains the theory:

[T]he problem with the confirmation bias is that it leads people to make very bad decisions and to arrive at crazy beliefs. And it’s weird, when you think of it, that humans should be endowed with a confirmation bias. If the goal of reasoning were to help us arrive at better beliefs and make better decisions, then there should be no bias. The confirmation bias should really not exist at all.But if you take the point of view of the argumentative theory, having a confirmation bias makes complete sense. When you’re trying to convince someone, you don’t want to find arguments for the other side, you want to find arguments for your side. And that’s what the confirmation bias helps you do.

The idea here is that the confirmation bias is not a flaw of reasoning, it’s actually a feature. It is something that is built into reasoning; not because reasoning is flawed or because people are stupid, but because actually people are very good at reasoning — but they’re very good at reasoning for arguing.

Lehrer concludes that the theory “paints a rather bleak portrait of human nature.” Certainly, we all see confirmation bias in others but struggle to recognize it in ourselves. The idea that this is how we’re wired can lead to a somewhat nihilistic view of the chances of figuring out “the truth.” But in the comments section, Mercier offers a different perspective:

[W]e’re not being quite as pessimistic as that. Even if the function of reasoning is not to pursue the truth directly, we suggest that reasoning can still lead us to better beliefs and decisions. The trick is to rely more on reasoning in group and, more specifically, on the evaluation of arguments as opposed to their production. The production of arguments is biased–as you describe. But argument evaluation ought to be fairly objective: after all, in many cases you’re better off being convinced rather than clinging to false beliefs… When people are in groups and argue about logical, mathematical or factual problems, they robustly converge on the best solution.

It almost sounds like he’s talking about Sweat Science! 🙂 So thanks to all who chime in with comments and critiques, as we all struggle to tear down each others’ confirmation biases.

[Thanks to Brian for pointing out the article.]

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