Improvement of association between confidence and accuracy after integration of discrete evidence over time

Abstract

When making decisions in real-life, we may receive discrete pieces of evidence during a time period. Although subjects are able to integrate information from separate cues to improve their accuracy, confidence formation is controversial. Due to a strong positive relation between accuracy and confidence, we predicted that confidence followed the same characteristics as accuracy and would improve following the integration of information collected from separate cues. We applied a Random-dot-motion discrimination task in which participants had to indicate the predominant direction of dot motions by saccadic eye movement after receiving one or two brief stimuli (i.e., pulse(s)). The interval of two pulses (up to 1s) was selected randomly. Color-coded targets facilitated indicating confidence simultaneously. Using behavioral data, computational models, pupillometry and EEG methodology we show that in double-pulse trials: (i) participants improve their confidence resolution rather than reporting higher confidence comparing with single-pulse trials, (ii) the observed confidence follow neural and pupillometry markers of confidence, unlike in weak and brief single-pulse trials. Overall, our study showed improvement of associations between confidence and accuracy in decisions resulted from the integration of evidence separated by different temporal gaps.