Editing Conjunction fallacy (section)

== Debiasing ==

Drawing attention to set relationships, using [[frequentism|frequencies]] instead of probabilities, or thinking [[venn diagram|diagrammatically]] are all methods that sharply reduce the error in some forms of the conjunction fallacy.<ref name="tk83" /><ref name="Hertwig & Gigerenzer (1999)" /><ref name="Mellers, Hertwig & Kahneman (2001)" /><ref name="Gigerenzer (1991)" />

In one experiment the question of the Linda problem was reformulated as follows:

<blockquote><p>There are 100 persons who fit the description above (that is, Linda's). How many of them are:</p>
* Bank tellers?  __ of 100
* Bank tellers and active in the feminist movement?  __ of 100</blockquote>

Whereas previously 85% of participants gave the wrong answer (bank teller and active in the feminist movement), in experiments done with this questioning the proportion of incorrect answers is dramatically reduced (to ~20%).<ref name="Gigerenzer (1991)">{{cite journal |last=Gigerenzer |first=G. |year=1991 |title=How to make cognitive illusions disappear: Beyond 'heuristics and biases.' |journal=European Review of Social Psychology |volume=2 |issue=1 |pages=83–115 |doi=10.1080/14792779143000033 |citeseerx=10.1.1.336.9826 }}</ref> Participants were forced to use a mathematical approach and thus recognized the difference more easily.

However, in some tasks only based on frequencies, not on stories, that used clear logical formulations, conjunction fallacies continued to occur dominantly, with only few exceptions, when the observed pattern of frequencies resembled a conjunction.<ref name="von Sydow (2011)">{{cite journal |last=von Sydow|first=M. |year=2011 |title=The Bayesian Logic of Frequency-Based Conjunction Fallacies. |journal=Journal of Mathematical Psychology|volume=55 |issue=2 |pages=119–139 |doi=10.1016/j.jmp.2010.12.001}}</ref>