Tuesday, February 27, 2007

Confirmatory Bias

Last semester, we discussed biases and irrationalities that violate the rationality assumption in economics. Another common bias is confirmatory bias. This describes the tendency of people to look for information that confirms their preconceived notions or a decision they made.

An example used by Tyler Cowen on his blog is how people eagerly read advertisements for a car after they have already bought the car: they do it as a way of confirming that they made the right decision. Another example that is a little different is when people notice or comment on a piece of jewelry or an expensive piece of clothing on a Walker student because they believe that all students from private schools are all rich. In that case, they are looking for information to confirm their preconceived notion.

Any other examples you can think of?

(Source: Marginal Revolution)

5 comments:

Anonymous said...

I'm not sure if this exactly counts as confirmatory bias, but sometimes after people have made a purchase they will also try to make others purchase the same thing. In the case of the car, I think that people want to think their car is great so they read good stuff about it to make themselves feel better. This same thing could be said about any purchase a person makes. No one likes to think that they wasted money or could've gotten something that wasn't the best. As for confirming sterotypes, people tend to only notice when the sterotype is applicable and ignore those that arn't defined by the sterotype. So they try to convince themselves with this "confirmatory bias."
-James C

Taylor said...

I also think that another way in which people confirm they bought the right product is by showing it off to people. After many people get something knew, they will show it off to their friends or family. They want to see there reaction to the product to make sure they also think it is as cool or awesome as the buyer did. Even if the purchase did violate the rationality assumption, the buyer only cares how other people react to his new product.

Anonymous said...

I find the confirmatory bias not only true when purchasing items or new products but especially valid when evaluating decisions. For example, while in search of your "best fit" college, you want to make sure you have made the best choices, so after having decided on a future school, you constantly check the website for cool information or updates. Also surprisingly enough, it is a relief when a friend goes out of their way to tell you that they think you'd do well at a certain college. This gives you huge amounts of confidence to aid the college search or reinforce already made decisions. A few kind words from a friend can be all that you need to help you when deciding colleges. Their opinions make the college process go by hundreds of times eaiser.

-john schmidt

Anonymous said...

An application of confirmatory bias is with any stereotype, such as the one mentioned about Walker students being rich. This is the same for any other group of people that people have preconcieved notions about, like French people. Everyone thinks French people are mean, and when I went to France, I did not find this to be the case any more so than meeting mean Americans, however my friends who take German in school (and I argue with incessantly over how the French are underrated) insist that they know someone who met a ton of really mean French people. Although they know me and trust my opinion, they had already decided that French people were mean, and therefore they brushed off my opinion as a personal bias of language in order for them to use their own confirmatory bias.

-Kate Vanderlip

Anonymous said...

I agree with John's comment. I think decisions are more crtisized by those who make them as either right or wrong. For example, I look back on my semester in Germany and decide whether it was a good decision. I constantly evaluate what the costs and benefits of that semster are. The support and reassurance that I received from family and friends go hand in hand with John's comment about the decision to attend a certain college.

Andreas W.