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Confidence and varieties of bias


Heathcote, A and Holloway, E and Sauer, J, Confidence and varieties of bias, Journal of Mathematical Psychology, 90 pp. 31-46. ISSN 0022-2496 (2019) [Refereed Article]

Copyright Statement

© 2018 Elsevier Inc.

DOI: doi:10.1016/


We test the proposition that response bias can have two different bases; reflecting either differing beliefs about the a priori likelihood of competing response alternatives, or their relative utilities. In evidence accumulation models, these two types of bias are thought to manifest as variations in the starting point for accumulation and threshold for responding, respectively. Although these two mechanisms are indistinguishable for linear accumulators in terms of accuracy and RT, Vickers’ (1979) balance-of-evidence hypothesis predicts they have dissociable effects on confidence. We derived ten ordinal predictions from these models and confirmed them at the level of group averages using traditional ANOVA analyses of results from a new experiment that manipulated the probability of correct responses and the rewards associated with them. However, individual effects were more variable, particularly with respect to the reward manipulation. We then used Bamber’s (1979) state–trace analysis to test the predicted dissociations using Bayes factors developed by Prince, Brown and Heathcote (2012) and Davis-Stober, Morey and Heathcote (2016). Once again, we found support at the aggregate level but more equivocal results for individuals. We discuss why individual results are to be preferred over aggregate results in state–trace analysis and draw the lesson that tailored designs are needed to obtain clear results from individual state–trace analyses.

Item Details

Item Type:Refereed Article
Keywords:confidence, response bias, individual results, aggregate results
Research Division:Psychology
Research Group:Cognitive and computational psychology
Research Field:Memory and attention
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in psychology
UTAS Author:Heathcote, A (Professor Andrew Heathcote)
UTAS Author:Holloway, E (Ms Eleanor Holloway)
UTAS Author:Sauer, J (Associate Professor Jim Sauer)
ID Code:129245
Year Published:2019 (online first 2018)
Web of Science® Times Cited:3
Deposited By:Psychology
Deposited On:2018-11-19
Last Modified:2019-07-02

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