Proceedings of the Annual Meeting of the Cognitive Science Society

Humans perceive dynamic events as seamless despite incomplete sensory input. This phenomenon, known as event completion, enables perception to appear coherent. However, it remains unclear whether observers have metacognitive insight into this completion when evaluating their own perceptual decisions. To address this question, we replicated the event completion effect using everyday activities (e.g., preparing breakfast) and examined metacognitive insight through metacognitive efficiency. Participants watched short video clips and judged whether a critical contact moment (e.g., grabbing a mug) had been visible and reported their confidence in each decision. Results showed reliable event completion, with participants frequently reporting contact even when it was absent but causally implied. Importantly, metacognitive efficiency was similar for causal and non-causal continuations, indicating that although inferred information can be experienced as perceived, observers' ability to evaluate the accuracy of their judgments remains comparable. These findings suggest that event completion does not impair metacognitive insight during perception.