Sleep deprivation disrupts error awareness and subsequent behavioural regulation

Sleep deprivation is known to impair cognitive performance, yet its effects on error awareness and subsequent behavioral adjustments remain incompletely understood. Here, we investigated how sleep loss affects the use of subjective performance evaluation to guide post-error adaptations. Thirty healthy adults completed a novel, gamified error awareness multi-rule Simon task once while well rested and once after 24 h of total sleep deprivation. On each trial, participants reported both their task response and subjective evaluation of response accuracy. This design allowed us to dissociate objective performance from subjective error awareness and to examine their influence on subsequent behavior over time. Sleep deprivation slowed responses, reduced accuracy, increased missed responses, and decreased the proportion of consciously detected errors. These effects increased with time on task and were accompanied by greater instability in sustained attention. Critically, post-error adjustments were driven by subjective error awareness rather than factual error commission. Reaction times slowed most strongly after subjectively perceived errors, including instances in which the preceding response had been objectively correct. Accuracy showed post-error decreases that were most pronounced following unaware errors. Sleep deprivation further altered these awareness-dependent control processes, particularly in later task phases. Together, these findings indicate that sleep deprivation disrupts both error awareness and the effective use of awareness signals for behavioral regulation. Statement of significanceOne night of total sleep deprivation reduces behavioral error awareness and disrupts post-error adjustments in a time-dependent manner. Crucially, our findings show that adaptive cognitive control is strongly shaped by subjective error awareness--even when that awareness is inaccurate. By identifying conscious performance evaluation as a key mechanism linking sustained attention, sleep loss, and behavioral regulation, this work highlights the importance of considering subjective awareness when studying adaptive control under fatigue.