Weighting mean and variability during confidence judgments.

Vincent De Gardelle,Pascal Mamassian,Suliann Ben Hamed

doi:10.1371/journal.pone.0120870

Abstract

Humans can not only perform some visual tasks with great precision, they can also judge how good they are in these tasks. However, it remains unclear how observers produce such metacognitive evaluations, and how these evaluations might be dissociated from the performance in the visual task. Here, we hypothesized that some stimulus variables could affect confidence judgments above and beyond their impact on performance. In a motion categorization task on moving dots, we manipulated the mean and the variance of the motion directions, to obtain a low-mean low-variance condition and a high-mean high-variance condition with matched performances. Critically, in terms of confidence, observers were not indifferent between these two conditions. Observers exhibited marked preferences, which were heterogeneous across individuals, but stable within each observer when assessed one week later. Thus, confidence and performance are dissociable and observers’ confidence judgments put different weights on the stimulus variables that limit performance.

Highlights

Some choices are easy and some are not
We seem to have a sense of this difference: sometimes we are confident and sometimes we are not. This feeling of confidence matters because it tells us whether we are ready to commit to the decision, or whether we should collect more information to avoid making a mistake. How we make such confidence judgments and which variables contribute to these judgments, is still unclear even in simple perceptual tasks
We investigate how observers make such confidence judgments during a 2-choice perceptual categorization task, where two factors can be dissociated that contribute to performance: signal strength and signal reliability ([14])

Summary

Introduction

We seem to have a sense of this difference: sometimes we are confident and sometimes we are not. This feeling of confidence matters because it tells us whether we are ready to commit to the decision, or whether we should collect more information to avoid making a mistake. How we make such confidence judgments and which variables contribute to these judgments, is still unclear even in simple perceptual tasks. In this domain, confidence is usually positively correlated with choice accuracy The two can be dissociated, as evidenced in several recent studies ([8,9,10,11,12,13])

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Results

Conclusion