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July 16, 2010

Confirmation bias in science

There's a decent meditation by Chris Lee on the problems of confirmation bias in science over at Nobel Intent, ArsTechnica's science corner. In its simplest form, confirmation bias is a particularly nasty mistake to make for anyone claiming to be a scientist. Lee gives a few particularly egregious (and famous) examples, and then describes one of his own experiences in science as an example of how self-corrective science works. I particularly liked the analogy he uses toward the end of the piece, where he argues that modern science is like a contact sport. Certainly, that's very much what the peer review and post-publication citation process can feel like.

Sometimes, however, it can take a long time for the good ideas to emerge out of the rough and tumble, particularly if the science involves complicated statistical analyses or experiments, if good data is hard to come by (or if the original data is unavailable), if there are strong social forces incentivizing the persistence of bad ideas (or at least, if there's little reward for scientists who want to sort out the good from the bad, for instance, if the only journals that will publish the corrections are obscure ones), or if the language of the field is particularly vague and ill-defined. [1]

Here's one of Lee's closing thoughts, which I think characterizes how science works when it is working well. The presence of this kind of culture is probably a good indicator of a healthy scientific community.

This is the difference between doing science from the inside and observing it from the outside. [Scientists] attack each other's ideas mercilessly, and those attacks are not ignored. Sometimes, it turns out that the objection was the result of a misunderstanding, and once the misunderstanding is cleared up, the objection goes away. Objections that are relevant result in ideas being discarded or modified. And the key to this is that the existence of confirmation bias is both acknowledged and actively fought against.


[1] Does it even need to be said?

posted July 16, 2010 04:55 PM in Scientifically Speaking | permalink