TY - JOUR T1 - Dynamic expressions of confidence within an evidence accumulation framework JF - bioRxiv DO - 10.1101/2020.02.18.953778 SP - 2020.02.18.953778 AU - Kobe Desender AU - Tobias H. Donner AU - Tom Verguts Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/04/02/2020.02.18.953778.abstract N2 - Human observers can reliably report their confidence in the choices they make. An influential framework conceptualizes decision confidence as the probability of a decision being correct, given the choice made and the evidence on which it was based. This framework accounts for three diagnostic signatures of human confidence reports, including an opposite dependence of confidence on evidence strength for correct and error trials. However, the framework does not account for the temporal evolution of these signatures, because it only describes the transformation of a static representation of evidence into choice and the associated confidence. Here, we combine this framework with another influential framework: dynamic accumulation of evidence over time. We propose that confidence reflects the probability of being correct, given the choice and accumulated evidence up until that point. The resulting model predicts that the diagnostic signatures of confidence depend on time; most critically, it predicts a stronger opposite dependence of confidence on evidence strength and choice correctness as a function of time. We tested, and confirmed, these predictions in human behaviour during random dot motion discrimination, in which confidence judgments were queried at different points in time. We conclude that human confidence reports reflect the dynamics of the probability of being correct given the accumulated evidence and choice.Author summary Humans are able to report a sense of confidence in the accuracy of a choice. An influential framework states that confidence reflects the probability that a choice is correct. We combined human experimenting with computational modelling and extended this notion in the time domain, thus to formally describe the dynamics of confidence. Both human data and our model show that the sense of confidence depends on the point in time at which it is queried. We conclude that human confidence reports reflect the dynamics of the probability of a choice being correct. ER -