How Overconfidence Bias Influences Suboptimality in Perceptual Decision Making

Marine Hainguerlot*, Thibault Gajdos, Jean Christophe Vergnaud, Vincent de Gardelle

*Corresponding author for this work

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In perceptual decision making, it is often found that human observers combine sensory information and prior knowledge suboptimally. Typically, in detection tasks, when an alternative is a priori more likely to occur, observers choose it more frequently to account for the unequal base rate but not to the extent they should, a phenomenon referred to as “conservative decision bias” (i.e., observers do not shift their decision criterion enough). One theoretical explanation of this phenomenon is that observers are overconfident in their ability to interpret sensory information, resulting in overweighting the sensory information relative to prior knowledge. Here, we derived formally this candidate model, and we tested it in a visual discrimination task in which we manipulated the prior probabilities of occurrence of the stimuli.We measured confidence in decisions and decision criterion placement in two separate experimental sessions for the same participants (N= 69). Both overconfidence bias and conservative decision bias were found in our data, but critically the link that was predicted between these two quantities was absent. Our data suggested instead that when informed about the a priori probability, overconfident participants put less effort into processing sensory information.

Original languageEnglish
Pages (from-to)537-548
Number of pages12
JournalJournal of Experimental Psychology: Human Perception and Performance
Issue number4
Publication statusPublished - 2023

Bibliographical note

Funding Information:
This research was supported by the Agence Nationale de la Recherche (ANR-16-CE28-0002, ANR-16-ASTR-0014 to Vincent de Gardelle), the Région Provence-Alpes-Côte d’Azur (CREMCO, 2012–2016 to Thibault Gajdos), and by University Paris 1 (doctoral grant to Marine Hainguerlot). The authors declare no competing interests

Publisher Copyright:
© 2023 American Psychological Association


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