jimrandomh comments on So You Think You're a Bayesian? The Natural Mode of Probabilistic Reasoning - Less Wrong

48 Post author: Matt_Simpson 14 July 2010 04:51PM

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Comment author: JanetK 15 July 2010 09:27:30AM 6 points [-]

Your idea that the subjects are not taking the question seriously is a good one.

I had a discussion with someone about a very similar real life 'Linda'. It was finally resolved by realizing that the other person didn't think of 'and' and 'or' as defined terms that always differed and was quite put out that I thought he should know that. To put it in 'Linda' terms: he know that Linda was a feminist and doubted that she was a teller. This being the case the 'and' should be thought of as an 'or' and b was more likely than a. Why would anyone think differently? It kind of blew my mind that I was being accused of being sloppy or illogical by using the fixed defined meaning for 'and' and 'or'. I have since that time noticed that people actually often have this vagueness about logical terms.

Comment author: jimrandomh 15 July 2010 01:46:26PM 2 points [-]

That suggests another variant of the Linda problem: replace the "and" with "and also", and leave the rest unchanged. If this makes a big difference, it would suggest that many of the people who fail on the Linda problem fail for linguistic reasons (they have the wrong meaning for the word "and") rather than logical reasons.

Comment author: Sperling 15 July 2010 10:26:56PM *  4 points [-]

Many subjects fail to recognize that when a 6-sided die with 4 green faces and 2 red faces will be rolled several times, betting on the occurrence of the sequence GRRRRRG is dominated by betting on the sequence RRRRRG, when the subject is given the option to bet on either at the same payoff. This (well, something similar, I didn't bother to look up the actual sequences used) is cited as evidence that more is going on than subjects misunderstanding the meaning of "and" or "or". Sure, some subjects just don't use those words as the experimenters do, and perhaps this accounts for some of why "Linda" shows such a strong effect, but it is a very incomplete explanation of the effect.

Explanations of "Linda" based on linguistic misunderstandings, conversational maxims, etc., generally fail to explain other experiments that produce the same representativeness bias (though perhaps not as strongly) in contexts where there is no chance that the particular misunderstanding alleged could be present.

Comment author: JanetK 15 July 2010 05:21:39PM 1 point [-]

Good idea. At the next such situation, I'll try that. Hopefully it will not be soon but you never know.