Master's Thesis from the year 2022 in the subject Psychology - Cognition, grade: B, Stockholm University, language: English, abstract: Sleep restriction is common in adults and has been linked to impairments in cognition, such as memory performance. However, less is known about how sleep restriction affects metacognition, the ability to monitor one's cognitive processes. This experimental study aimed to (i) investigate if sleep restriction negatively impacts episodic memory performance and (ii) to examine if sleep restriction negatively affects two aspects of metacognition (confidence bias and metacognitive sensitivity). Using a within-subjects design, 148 participants performed an episodic memory task after two nights of restricted sleep (4h/night) and two nights of saturated sleep (9h/night) in a randomized order. The episodic memory task comprised the encoding and retrieval of indoor and outdoor images. Participants provided a confidence rating for each trial. Mixed model analyses revealed that participants performed less accurately after sleep restriction, were more confident in their performance, and had lower metacognitive sensitivity.