The impact of feedback on metacognition: Enhancing in easy tasks, impeding in difficult ones.

Metacognition refers to the ability to monitor and introspect upon cognitive performance. Abundant research suggests that individual metacognition is easily affected by feedback in daily life, but how feedback affects metacognition in perceptual decision-making remains unclear. Here we investigated how trial-by-trial feedback shapes perceptual metacognition in two experiments with either high (n = 82) or low difficulty (n = 90). Participants were randomly divided into a feedback group in which participants received trial-by-trial performance feedback or a no-feedback group. Results showed that, in the high-difficulty task, participants in the feedback group revealed inferior metacognitive performance than the no-feedback group, manifested as decreased metacognitive efficiency while controlling for performance sensitivity. In the low-difficulty task, however, participants in the feedback group had higher metacognitive efficiency than the no-feedback group. The distinct patterns of findings in the two experiments indicate that whether feedback promotes or impedes metacognition is adjusted by task difficulty.