In routine operational tasks, fatigue often shows up as more errors
In aircraft maintenance, students with on-the-job training reported that mental fatigue significantly impaired attention, concentration, memory recall, inspection accuracy, and decision-making, and they strongly agreed that fatigue contributed to increased human error and reduced compliance with procedures [3]. This is a survey-based study of 101 students, so it captures perceived effects rather than directly measured error rates in real maintenance work.
In a simulated air traffic control task, taking microbreaks helped preserve task performance, and a walking microbreak was particularly effective in reducing operational errors [4]. The study used ATC-naïve participants in a simplified simulation, so the results show that fatigue recovery can reduce errors in a controlled operational setting, but they do not directly measure fatigue-related error increases without breaks.
For high-stakes strategic decisions, the link to fatigue is discussed but not directly measured
A methodological paper on cognitive monitoring for safety-critical tasks—such as air traffic controllers, surgeons, or mission control personnel—identifies fatigue and stress as key challenges that require adaptive monitoring to reduce human error and support decision-making [5]. However, this paper presents a framework rather than an empirical test of whether fatigue increases errors in high-stakes strategic decisions. So the evidence for that context is indirect: it suggests fatigue is a concern, but it does not show a consistent error increase.
Why effect sizes might differ: task demands and the fatigue–performance gap
Task complexity matters. In athletes performing cognitive tasks, higher error rates and longer reaction times occurred in arithmetic and mixed-task conditions compared to simpler Stroop and Flanker tasks [1]. This suggests that more demanding tasks may be more sensitive to fatigue-related performance drops, which could explain why effect sizes vary across operational and strategic settings.
Fatigue does not always translate immediately into worse performance. In the same athlete study, subjective fatigue increased significantly over time, but behavioral performance did not decline, supporting a distinction between mental fatigue and fatigability—the latter being the observable decline in performance [1]. This gap means that studies measuring only subjective fatigue may overestimate error increases, while studies measuring only performance may miss fatigue entirely.
In team collaborative tasks, reduced operational capability is expected to increase error rates, and a Bayesian network model was developed to predict continuous operational capability and its changing trend [2]. This modeling approach implies that error increases depend on how capability evolves over time, which can differ across tasks and teams, contributing to varying effect sizes.
Sources used in this answer
Neural and behavioral markers of mental fatigue and fatigability in athletes: an EEG study using single and mixed cognitive tasks.
In athletes performing cognitive tasks, subjective fatigue increased over time without behavioral performance decline, and error rates were higher in arithmetic and mixed-task conditions than in simpler tasks.
A Bayesian Network-Based Prediction Method for Continuous Operational Capability During Team Collaborative Tasks
A Bayesian network model was developed to predict continuous operational capability in team collaborative tasks, based on the expectation that reduced capability increases error rates.
The Impact of Mental Fatigue on Aircraft Maintenance Tasks Among Aircraft Maintenance Students
Aircraft maintenance students reported that mental fatigue significantly impaired attention, concentration, memory, inspection accuracy, and decision-making, and contributed to increased human error.
Effects of meditation or walking as a microbreak on fatigue recovery during simulated air traffic control tasks
In a simulated air traffic control task, microbreaks helped preserve performance, with walking microbreaks particularly effective in reducing operational errors.
Building Trustworthy Cognitive Monitoring for Safety-Critical Human Tasks: A Phased Methodological Approach
A phased methodological approach for cognitive monitoring in safety-critical tasks identifies fatigue and stress as challenges to address for reducing human error and supporting decision-making.