Metacognitive Monitoring of the Visual System in Sustained Attention

The state of the human visual system undergoes moment-to-moment fluctuations due to various neurocognitive factors, such as mind wandering and vigilance. To deal with this instability in the visual system through timely intervention (e.g., controlling attention and taking a rest), monitoring the state of the visual system might be crucial. In this study, we investigated whether and how people can monitor the state of their own visual system during sustained attention tasks. Participants were required to report the orientation (Experiment 1) or presence (Experiment 2) of a Gabor target every two seconds with a confidence judgment for their response. We presumed that if participants could monitor the state of the visual system, confidence judgments would accurately track task performance fluctuations. In Experiment 1, we observed a positive correlation between orientation discrimination performance and confidence, supporting accurate metacognitive monitoring. Experiment 2 aimed to elucidate the mechanism of metacognitive monitoring: direct monitoring of the state of the visual system (e.g., current states of attention and vigilance) versus indirect monitoring based on the visibility of a target. To address this, we employed a target detection task. Specifically, in detection, confidence judgments can be informed by target visibility in judgments about target presence (e.g., high confidence for high visibility) but not target absence. Therefore, if participants monitor only target visibility, their confidence judgments would correlate with performance fluctuations for target-present responses but not for target-absent responses. We observed a positive correlation between detection performance and confidence for target-present responses, but no correlation for target-absent responses. These results suggest that, in sustained attention, metacognitive monitoring of the visual system relies on the visibility of a target, rather than the state of the visual system itself.