What is it about?
People often rely on how confident they feel to decide whether to stick with their beliefs or revise them after hearing others’ opinions. Typically, strong confidence helps stabilize beliefs, making people less likely to change their minds. In this study, we examined how sleep deprivation affects this process. Across two experiments, participants completed a decision-making task in which they received agreement or disagreement from a peer and could update their beliefs and confidence. We compared performance after a normal night of sleep and after 24 hours without sleep. We found that sleep deprivation consistently made people more likely to change their minds, regardless of whether others agreed or disagreed. Importantly, it weakened the usual role of confidence: even when participants initially felt very confident, they were more likely to revise their beliefs. In a second experiment, when participants were not allowed to change their beliefs, sleep deprivation led to larger drops in confidence, especially for strongly held beliefs. These confidence changes predicted later belief change. Overall, the results show that sleep loss disrupts how people use confidence to regulate belief updating.
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Why is it important?
This study shows that sleep deprivation does not simply make people more suggestible, it fundamentally disrupts the mechanism that normally protects our beliefs from unnecessary change. Under normal conditions, confidence acts as a “gatekeeper,” helping people resist changing their minds when they are likely to be correct. When sleep deprived, this protective function breaks down. As a result, people may revise even well-founded beliefs too readily, or fail to rely on their own judgment appropriately. This has important real-world implications. Many high-stakes decisions, such as in healthcare, emergency services, or security, are made under sleep-deprived conditions. Our findings suggest that in these situations, individuals may become less stable in their decisions and less able to use their own confidence as a reliable guide. More broadly, the study highlights how physiological states like sleep loss can shape social decision-making and belief formation, which are central to everyday reasoning and interactions.
Perspectives
What I find most striking about these results is not just that people change their minds more when sleep deprived, but why this happens. Rather than simply becoming more influenced by others, participants seemed to lose access to a key internal signal, confidence, that normally helps regulate when to hold on to or revise a belief. This suggests that sleep deprivation affects metacognition in a very specific way: it disrupts the link between how certain we feel and how we act on that certainty. In other words, people may still experience confidence, but they no longer use it effectively. For me, this raises interesting questions about decision-making in real-world settings where sleep loss is common. It also opens the door to studying how other states, such as stress or fatigue, might similarly interfere with the mechanisms that guide belief stability.
Charlotte Anckaert
Universite Libre de Bruxelles
Read the Original
This page is a summary of: Sleep deprivation disrupts the gatekeeping role of confidence in belief updating., Journal of Experimental Psychology Applied, March 2026, American Psychological Association (APA),
DOI: 10.1037/xap0000570.
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