Bias in confidence: A critical test for discrete-state models of change detection

Abstract

Ongoing discussions on the nature of storage in visual working memory have mostlyfocused on two theoretical accounts: On one hand we have a discrete-state accountpostulating that information in working memory is supported with high fidelity for alimited number of discrete items by a given number of “slots”, with no informationbeing retained beyond these. In contrast with this all-or-nothing view, we have acontinuous account arguing that information can be degraded in a continuous manner, reflecting the amount of resources dedicated to each item. It turns out that the core tenets of this discrete-state account constrain the way individuals can express confidence in their judgments, excluding the possibility of biased confidence judgments. Importantly, these biased judgments are expected when assuming a continuous degradation of information. We report two studies showing that biased confidence judgments can be reliably observed, a finding that rejects a large number of discrete-state models, dismissing the idea that change-detection judgments consist of a mixture of guesses and high-fidelity memory representations.