Adelaide Research and Scholarship : Schools and Disciplines : Australian School of Petroleum : ASP Publications

Type:	Conference paper
Title:	Seeing is believing: Priors trust and base rate neglect
Author:	Welsh, Matthew Brian Navarro, Daniel Joseph
Citation:	Proceedings of the 29th Annual Cognitive Science Society, 1-4 August, 2007 / pp. 701-706.
Publisher:	Cognitive Science Society
Issue Date:	2007
ISBN:	097683183X
Conference Name:	CogSci 2007 Annual Conference of the Cognitive Science Society (29th : 2007 : Nashville, Tennessee, USA)
School/Discipline:	Australian School of Petroleum
Abstract:	Tversky and Kahneman (1974) described an effect they called `insensitivity to prior probability of outcomes', better known as base rate neglect (Bar-Hillel, 1980). This describes peo- ple's tendency to underweight prior information in favor of new data. Probability theory requires these prior probabilities to be taken into account, via Bayes' theorem, when deter- mining an event's posterior probability. The fact that most people fail to do so has been taken as evidence of human ir- rationality and, by other authors, of a mismatch between our cognitive processes and the questions being asked (Cosmides & Tooby, 1996; Gigerenzer & Hoffrage, 1995). In contrast to both views, we suggest that simplistic Bayesian updating us- ing given base rates is not always a rational strategy. Instead, we reconsider Bar-Hillel's original relevance theory, and ar- gue that, since base rates differ in their perceived degree of trustworthiness they are, accordingly, rationally discounted by people.
Keywords:	base rate neglect; Bayesian updating; cognitive bias; decision-making
Description:	Copyright © 2007 by the Cognitive Science Society, Inc.
RMID:	0020074688
Published version:	http://www.cogsci.rpi.edu/CSJarchive/Proceedings/2007/forms/authors5.htm http://www.cogsci.rpi.edu/CSJarchive/Proceedings/2007/docs/p701.pdf
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Appears in Collections:	ASP Publications

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