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On the determinants of the conjunction fallacy: probability versus inductive confirmation
Katya Tentori1, Vincenzo Crupi2, Selena Russo1
1Department of Cognitive Sciences and Education.
Journal of Experimental Psychology. General
|July 25, 2012
Summary
This study challenges existing explanations of the conjunction fallacy, proposing that inductive confirmation, not averaging or random error, better explains this cognitive bias in human reasoning.
Area of Science:
- Cognitive Psychology
- Decision Making
- Bayesian Theory
Background:
- Recent theories explain the conjunction fallacy via averaging rules or random error in probability assessment.
- These models suggest fallacy rates increase with the perceived probability of conjuncts.
Purpose of the Study:
- To contrast averaging/error models with a confirmation-theoretic account of the conjunction fallacy.
- To investigate the role of inductive confirmation in conjunction fallacy occurrences.
Main Methods:
- Four experimental studies systematically manipulated and dissociated judged probability and confirmation of added conjuncts.
- Compared predictions of averaging/error models against a confirmation-based model.
Main Results:
- Results consistently supported the confirmation-theoretic account over competing models.
- The conjunction fallacy was found to depend on the perceived inductive confirmation of the added conjunct.
Conclusions:
- The study provides evidence for inductive confirmation as a key factor in the conjunction fallacy.
- This finding offers a novel perspective on human inductive reasoning and cognitive biases.
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