Comments on: Cognitive Bias: Conjunction Fallacy

By: Michael Graham Richard

Michael Graham Richard — Fri, 16 Nov 2007 16:23:28 +0000

Steve,

The probability percentages are not important.

Even if we change the probabilities from 50% and 95% to 0.01% and 95%, #1 is still more likely than #2. That’s the point. Yet people when asked (without knowing the probabilities %) picked #2 as more likely by a 85% ratio, hence the conjunction bias.

By: Steve Olson

Steve Olson — Fri, 16 Nov 2007 15:02:31 +0000

My brain doesn’t get it. I understand the fallacy, but I don’t understand the example. We have some information that may lead you to conclude she is a feminist but we aren’t given any information to suggest she even has a job let alone one in financial services. Isn’t is just as likely she is a grave digger as a bank teller? or a trust fund baby or a lottery winner or homeless? Did I miss something? At first glance it appears extremely unlikely she is a bank teller, which makes #1 unlikely and #2 even more unlikely.

By: Aidenn

Aidenn — Fri, 16 Nov 2007 01:14:56 +0000

It seems like the mistake could just be one of how the question is phrased. When we are given multiple options, it is assumed that they are exclusive. Therefore someone presented with that question might interpret 1 to mean “Linda is a bank teller and not a member of the feminist movement”