Linear Ballistic Accumulator Models of Confidence and Response Time

A major target for evidence accumulation models of decision-making has been the development of a joint account of confidence, accuracy, and latency. While successful extensions to confidence have been made, there remains a lack of consensus as to how confidence is generated and there have been few comparisons between existing models. In this work, we developed and compare three different mechanisms for confidence generation in the linear ballistic accumulator framework (S. D. Brown & Heathcote, 2008). These take the form of a.) multi-alternative decisions among all of the confidence options as a competitive race, b.) the balance of evidence between the response alternatives (the multiple threshold race; Reynolds et al., in revision), and c.) confidence being inversely proportional to the amount of subjective time that has elapsed in the decision, which is measured as a separate accumulation process. Each theory was tested against two experiments that manipulated the number of confidence options in a decision (Experiment 1) or the amount of time pressure (Experiment 2). All theories cleared the empirical hurdles, but there were also subtle differences between each of the theories in their ability to address the data: although all models showed generally adequate parameter recovery, the Confidence Accumulator failed to produce theoretically sensible parameter shifts across confidence-scale conditions whereas the Timing theory was unable to address fast low-confidence patterns in individual participants; meanwhile, both the MTR and the Timing theory had questionable plausibility in addressing the double-increase pattern of confidence.