Dynamics of Postdecisional Processing of Confidence

Most cognitive theories assume that confidence and choice happen simultaneously and are based on the same information. The 3 studies presented in this article instead show that confidence judgments can arise, at least in part, from a postdecisional evidence accumulation process. As a result of this process, increasing the time between making a choice and confidence judgment improves confidence resolution. This finding contradicts the notion that confidence judgments are biased by decision makers seeking confirmatory evidence. Further analysis reveals that the improved resolution is due to a reduction in confidence in incorrect responses, while confidence in correct responses remains relatively constant. These results are modeled with a sequential sampling process that allows evidence accumulation to continue after a choice is made and maps the amount of accumulated evidence onto a confidence rating. The cognitive modeling analysis reveals that the rate of evidence accumulation following a choice does slow relative to the rate preceding choice. The analysis also shows that the asymmetry between confidence in correct and incorrect choices is compatible with state-dependent decay in the accumulated evidence: Evidence consistent with the current state results in a deceleration of accumulated evidence and consequently evidence appears to have a decreasing impact on observed confidence. In contrast, evidence inconsistent with the current state results in an acceleration of accumulated evidence toward the opposite direction and consequently evidence appears to have an increasing impact on confidence. Taken together, this process-level understanding of confidence suggests a simple strategy for improving confidence accuracy: take a bit more time to make confidence judgments.