Neural mechanisms of metacognitive improvement under speed pressure

The ability to accurately monitor the quality of one’s choices (i.e., metacognition) is critical for adaptive decision-making. Metacognition improves under speed pressure, possibly due to elaborated post-decisional evidence processing. Here, we investigated the neural processes that regulate metacognition during decision-making using time-resolved analyses of electroencephalographic (EEG) data. Participants performed a motion discrimination task under short and long response deadlines. Following each response, participants rated their desire to change their mind. To understand the interplay between decision-making and metacognition at a neural level, we characterised the centro-parietal positivity (CPP), a neural correlate of evidence accumulation. Participants were faster and less accurate under speed pressure, but showed superior metacognition. This effect was driven by improved error awareness and was accompanied by larger CPP amplitude on short deadline trials. Under both short and long deadlines, greater pre-decisional CPP amplitude was associated with correct responses and predicted less desire to change one’s mind, whereas greater post-decisional CPP amplitude was associated with incorrect responses and predicted more desire to changes one’s mind. Our results suggest speed pressure alters the evidence accumulation process, leading to changes in metacognitive readout relative to long response deadlines.