When Your Best Thinking Stops Working

 Why Do Smart People Make Bad Decisions Under Stress?

You have built your career on making sound decisions. You have navigated complexity, uncertainty, and responsibility before. Yet many experienced professionals notice a subtle shift over time: decisions that once felt clear now require more effort, familiar strategies no longer land as expected, and judgment under pressure feels less reliable.

This experience is neither personal weakness nor loss of competence. It reflects well-documented changes in how cognitive systems function under sustained stress.

Why This Question Matters

The question “Why do I make bad decisions?” is often framed incorrectly. It is rarely about intelligence, motivation, or discipline. Instead, research shows that stress alters the conditions under which decisions are formed, affecting attention, working memory, emotional regulation, and risk evaluation across a wide range of professional domains, including healthcare, aviation, management, academia, sales, policing, and firefighting (Carroll, 2023; Ng et al., 2019).

What follows is not a motivational explanation, but a mechanistic one.

How Stress Changes Decision-Making Quality

Attentional Narrowing and Reduced Information Gathering

Under stress, attention narrows. The perceptual field contracts, and individuals seek less information from their environment. This reduction in environmental scanning increases the likelihood that relevant cues are missed, and alternatives are evaluated incompletely, particularly in complex or dynamic situations (Carroll, 2023; Byrnes, 2002).

In aviation, this narrowing can result in missed cockpit data. In executive contexts, it may manifest as overlooked strategic options or underestimated risks. This is not carelessness, but a cognitive adaptation aimed at reducing load.

One of the earliest and most consequential changes under pressure is attentional narrowing - a contraction of perceptual and informational scope that often goes unnoticed by the decision-maker.

We explore this mechanism in detail in Why Smart Leaders Miss Obvious Signals Under Pressure.

Working Memory and Executive Function Under Load

Stress impairs working memory and executive functions responsible for integrating information, comparing alternatives, and maintaining cognitive flexibility. Reduced working memory capacity increases perseveration on suboptimal choices, elevates error rates, and limits the ability to hold multiple constraints in mind simultaneously (Carroll, 2023; Ng et al., 2019; Buelow, 2020).

For senior professionals, this often feels like “thinking becoming harder,” even though the underlying issue is capacity under load, not capability.

For a focused analysis of how stress degrades working memory and leads to rigid decision patterns, see : Why stress narrows thinking and leads to rigid decisions.

Increased Reliance on Heuristics

As cognitive demand increases, decision-making shifts toward automatic or intuitive processes. Well-learned heuristics and familiar response patterns are applied more frequently, sometimes beyond their appropriate context. While heuristics are efficient in stable environments, under changing conditions they can lead to rushed decisions, outdated solutions, and insufficient consideration of alternatives (Leder, Häusser, & Mojzisch, 2015; Dwyer, Holt, & Lester, 2026; Gelman & Kliger, 2021).

This explains why experienced leaders may rely on frameworks that previously worked, even when situational assumptions have shifted.

Emotional and Behavioural Effects of Stress

Anxiety, Distraction, and Indecisiveness

Stress elevates anxiety and fear responses, which compete with task-relevant attention. This can result in distraction, overthinking, or delayed commitment, particularly in high-pressure environments where emotional load is high (Byrnes, 2002; Steinrücke, Veldkamp, & de Jong, 2019; Amemiya et al., 2020).

Reduced Confidence and Increased Reaction Time

Stress is associated with reduced confidence in one’s own decisions and longer reaction times, often producing hurried or less optimal choices once action is finally taken (Daylamani-Zad, Spyridonis, & Al-Khafaaji, 2022; Almazrouei, Dror, & Morgan, 2023).

Risk-Taking and Reward Processing

Research indicates a small but significant relationship between stress and increased risk-taking or reward-seeking behaviour. Stress disrupts learning from rewards and punishments and increases the likelihood of disadvantageous decisions, particularly under risk conditions (Buelow, 2020; Gelman & Kliger, 2021; Pabst, Brand, & Wolf, 2013).

Impact on Teams and Organisations

Stress does not only affect individuals.

• Team communication and group performance deteriorate under stress, with reduced sensitivity to others and impaired coordination observed in settings such as operating rooms and management teams (Ng et al., 2019; Leder et al., 2015).

• Job performance and service quality decline in sales and customer-facing roles, where stress from interpersonal conflict or high demands undermines commitment to quality and customer perception (Mulki & Wilkinson, 2017).

• Leadership decision quality is compromised under sustained work pressure, correlating with reduced productivity and effectiveness among academic and organisational leaders (Al-Zoubi et al., 2024).

Domain-Specific Evidence

• Aviation: Stress increases the likelihood of missed information, misjudged situations, and failure to consider viable alternatives, directly affecting safety outcomes (Carroll, 2023).

• Forensic and emergency services: Stress leads to longer reaction times, increased distraction, and more inconclusive or risk-averse decisions under high cognitive demand (Daylamani-Zad et al., 2022; Almazrouei et al., 2023; Almazrouei et al., 2024).

• Management and strategy: Under stress, managers are more likely to rush decisions, overlook alternatives, and neglect contextual nuance, increasing error rates and strategic risk (Leder et al., 2015; Dwyer et al., 2026).

Moderating Factors and Complexity

Experience and Individual Differences

Experience moderates, but does not eliminate, the effects of stress. Experienced surgeons and professional officials demonstrate greater stability than novices, yet still show decision degradation once stress exceeds adaptive capacity (Chrouser et al., 2018; Pereira Vargas et al., 2026).

Timing and Context

Stress effects vary depending on timing and context. Moderate stress may temporarily enhance performance, but prolonged or excessive stress reliably impairs decision quality (Steinrücke et al., 2019; Pabst et al., 2013; Buchanan & Preston, 2014).

A Bidirectional Relationship

Stress affects decision quality, and decision-making itself can be a source of stress. This bidirectional relationship reinforces cognitive strain over time, particularly in high-responsibility roles (Wong et al., 2019).

What This Means in Practice

The key issue is not stress itself, but decision-making under sustained load. Traditional stress management strategies may support recovery, but they do not address how decisions are formed in real time, under uncertainty.

A more useful question than “Why am I making bad decisions?” is:

Under what conditions does my decision-making become unreliable?

A Structured Starting Point

If decision quality matters in your role, guessing is not a strategy.

The Default Mode Diagnostic is a short, research-informed tool designed to help identify how your thinking adapts under pressure, where cognitive load accumulates, and which decision patterns may be increasing risk without being immediately visible.

You can access it via the hero section at
www.appliedbrainlab.com 

No motivation. No performance promises. Just a clearer view of how your cognition is currently operating.

References

Almazrouei, M., Dror, I., & Morgan, R. (2023). The possible impact of stress on forensic decision-making: An exploratory study. Forensic Science International: Mind and Law, 4. https://doi.org/10.1016/j.fsiml.2023.100125 

Almazrouei, M., Kukucka, J., Morgan, R., & Levy, I. (2024). Unpacking workplace stress and forensic expert decision-making: From theory to practice. Forensic Science International: Synergy, 8. https://doi.org/10.1016/j.fsisyn.2024.100473 

Al-Zoubi, Z., AlKaabi, A., Qablan, A., Bataineh, O., & Bany Issa, H. (2024). The impact of work pressure on decision-making effectiveness among department heads in faculties of educational sciences. PLOS ONE, 19. https://doi.org/10.1371/journal.pone.0304584 

Amemiya, S., Ishida, M., Kubota, N., Nishijima, T., & Kita, I. (2020). Stress drives deliberative tendencies by influencing vicarious trial and error in decision making. Neurobiology of Learning and Memory, 174. https://doi.org/10.1016/j.nlm.2020.107276 

Buchanan, T., & Preston, S. (2014). Stress leads to prosocial action in immediate need situations. Frontiers in Behavioral Neuroscience, 8. https://doi.org/10.3389/fnbeh.2014.00005 

Buelow, M. (2020). Anxiety: State-dependent stress, generalized anxiety, social anxiety, posttraumatic stress disorder, and obsessive–compulsive disorder. In Risky Decision Making in Psychological Disorders. https://doi.org/10.1016/B978-0-12-815002-3.00005-X 

Byrnes, J. (2002). The development of decision-making. Journal of Adolescent Health, 31. https://doi.org/10.1016/S1054-139X(02)00503-7 

Carroll, M. (2023). Decision making in aviation. In Human Factors in Aviation and Aerospace. https://doi.org/10.1016/B978-0-12-420139-2.00016-2 

Chrouser, K., Xu, J., Hallbeck, S., Weinger, M., & Partin, M. (2018). The influence of stress responses on surgical performance and outcomes. The American Journal of Surgery, 216. https://doi.org/10.1016/j.amjsurg.2018.02.017 

Daylamani-Zad, D., Spyridonis, F., & Al-Khafaaji, K. (2022). A framework and serious game for decision making in stressful situations. International Journal of Human-Computer Studies, 162. https://doi.org/10.1016/j.ijhcs.2022.102790 

Dwyer, G., Holt, G., & Lester, R. (2026). Effective indicators to enable robust decision making in the Murray–Darling Basin. Ecological Informatics, 94. https://doi.org/10.1016/j.ecoinf.2026.103613 

Gelman, S., & Kliger, D. (2021). The effect of time-induced stress on financial decision making. Journal of Economic Behavior & Organization, 185. https://doi.org/10.1016/j.jebo.2020.10.022 

Leder, J., Häusser, J., & Mojzisch, A. (2015). Exploring the underpinnings of impaired strategic decision-making under stress. Journal of Economic Psychology, 49. https://doi.org/10.1016/j.joep.2015.05.006 

Mulki, J., & Wilkinson, J. (2017). Customer-directed extra-role performance and emotional understanding. Australasian Marketing Journal, 25. https://doi.org/10.1016/j.ausmj.2017.04.002 

Ng, R., Chahine, S., Lanting, B., & Howard, J. (2019). Stress and resiliency in the operating room. Journal of Surgical Education, 76. https://doi.org/10.1016/j.jsurg.2018.07.025 

Pabst, S., Brand, M., & Wolf, O. (2013). Stress and decision making. Behavioural Brain Research, 250. https://doi.org/10.1016/j.bbr.2013.04.046 

Pereira Vargas, M., Cunningham, I., Mascarenhas, D., Sullivan, P., Holden, M., Carter, T., & Hancock, D. (2026). Operating under pressure. Psychology of Sport and Exercise, 83. https://doi.org/10.1016/j.psychsport.2025.103057 

Steinrücke, J., Veldkamp, B., & de Jong, T. (2019). Stress effects on analytical skills in decision games. Computers in Human Behavior, 99. https://doi.org/10.1016/j.chb.2019.05.014 

Wong, K., Hicks, L., Seuntjens, T., Trentacosta, C., Hendriksen, T., Zeelenberg, M., & van den Heuvel, M. (2019). Mindful parenting and decision-making. Frontiers in Psychology, 10. https://doi.org/10.3389/fpsyg.2019.00550