Psychology Behind Uncertainty: Why the Unknown Triggers Anxiety

Uncertainty is woven into everyday life, often in quiet and familiar ways. It appears when a student refreshes an exam portal repeatedly while waiting for results, when a working professional checks emails anxiously after hearing rumours of layoffs, or when someone rereads a short text message, trying to guess what it really means. These moments may seem ordinary, but they carry a shared psychological experience: not knowing what comes next. In essence, uncertainty refers to situations where outcomes cannot be predicted with confidence or clarity. While some individuals find open-ended possibilities exciting, many experience uncertainty as distressing, anxiety-provoking, or emotionally draining. 

Psychological research shows that discomfort with uncertainty is not random. People differ in how strongly uncertainty affects them, based on how they process information, regulate emotions, learn from past experiences, and develop personality traits. For some individuals,  uncertainty feels especially threatening and difficult to tolerate. This tendency is described as  Intolerance of Uncertainty (IU). IU refers to a relatively stable disposition in which uncertain situations are experienced as unacceptable or dangerous, even when there is little objective evidence that something negative will occur (Carleton, 2016).

Read More: Impact of Personality Traits on Cognitive Abilities

Understanding Uncertainty  

In psychology, uncertainty is not just about lacking information. It is about how the mind interprets the absence of certainty. Two people can face the same unknown situation, such as waiting for medical test results, but experience it very differently. Research distinguishes between:  

1. Objective uncertainty: the actual unpredictability of a situation  
2. Subjective uncertainty: how uncertain the situation feels to an individual  

Subjective uncertainty is what most strongly predicts emotional distress (Morriss et al.,  2022). This helps explain why some people find uncertainty to be far more taxing than others do.  

Intolerance of Uncertainty (IU) is the concept that helps understand why some people find uncertainty so much more challenging than others. In IU, an individual does not just dislike being uncertain, but it is also about how they feel and experience a situation where uncertainty exists as being threatening, overwhelming, or incapacitating, too. Research has  shown that it involves:  

• Overestimating the likelihood of a negative outcome occurring 
• Difficulty coping without clear answers  
• A strong need for predictability and control  
• Emotional distress when outcomes are unclear  

According to Carleton (2016), IU is a transdiagnostic factor because it is present in several psychological disorders rather than in a single type of disorder. 

Why the Human Brain Dislikes Uncertainty  

From an evolutionary standpoint, uncertainty could signal a potential threat. Early humans were able to identify unknown threats and react quickly. Therefore, the evolution of the human brain created the need to respond to uncertainty as if it existed in our environment. Modern research suggests that uncertainty activates:  

• The amygdala, which processes threat and fear  
• Brain networks involved in vigilance and error detection  
• Stress response systems, such as cortisol release

As a result, individuals may experience physical symptoms of anxiety—racing heart, restlessness, muscle tension—even when no immediate threat is present.

Cognitive effort (or cognitive load) increases due to IU. The brain prefers clear patterns and predictions. When outcomes are unknown:  

• The mind keeps generating possible scenarios  
• Attention becomes narrowly focused on “what if” thoughts  
• Mental fatigue increases  

This constant mental simulation can lead to worry and rumination, especially in individuals high in IU (Dugas et al., 2005).  

Read More: How the Amygdala Shapes Our Emotions and Behaviour

Emotional Responses to Uncertainty  

One of the more prominent areas of research within psychology shows that uncertainty can cause us to experience emotional states even when there will not be a negative outcome. 

1. Anxiety: It is the most common. Studies consistently show that IU predicts generalised, social and health anxiety, along with panic symptoms. As Carleton  (2016) states, people with high IU are not necessarily worried because something has gone wrong; they are anxious because there is a possibility of something going wrong.  
2. Fear: arises from knowledge of a threat, while anxiety arises from the absence of knowledge about what that threat may be; thus, the unknown is usually much more distressing compared to the known. This distress is due to our inability to create a mental plan on how we will respond to an uncertain environmental condition (Morriss et al., 2022).  
3. Emotional Amplification: Research also shows that uncertainty amplifies emotional reactions:  
   • Negative emotions feel more intense  
   • Emotional recovery takes longer  
   • Neutral events are interpreted more negatively  

The COVID-19 pandemic was one of the largest global examples of emotional distress, and the fear generated from the unknowns surrounding COVID-19 is a great example of how uncertainty affects one’s emotional state (Berenbaum et al., 2020). Research during this period showed that:  

• Higher IU predicted greater anxiety and depression  
• IU mediated the relationship between stress and mental health outcomes.
• Individuals with a high IU experience more of the psychological issue of worry and rumination compared to those without a high IU (Rettie & Daniels, 2021). 

Those in this research suggest that high degrees of uncertainty will cause many people to increase the level of psychological distress they experience daily.  

Decision-Making Under Uncertainty  

The role of uncertainty in decision-making is one of the larger research areas of psychology, with studies documenting that uncertainty has an impact on the manner in which a person will decide to act. The difficulties of making decisions based upon the IU have a much higher prevalence than those without IU. People who struggle with uncertainty are more likely to:  

• Delay decisions  
• Seek excessive reassurance  
• Avoid choices altogether  

This avoidance temporarily reduces anxiety but strengthens fear of uncertainty over time  (Shihata et al., 2016). A large body of classic decision-making literature – including the Ellsberg paradox – has shown that we prefer to choose or act upon risks that we know about, versus those risks that we may not be able to judge the outcome of correctly, even if the latter has a significantly better chance of being the outcome (Ellsberg, 1961).

This phenomenon is referred to as ambiguity aversion, and it demonstrates a person’s discomfort with uncertainty and not the soundness of the risk calculation’s return of a level of risk and reward. In everyday life, this is demonstrated in the following manner:  

• Staying in an unsatisfying job due to fear of uncertain alternatives  
• Remaining in unhealthy relationships because the outcomes of change are unknown 
• Excessive planning or research done before certain minor decisions  

Uncertainty, Rumination and Worry  

Uncertainty fuels repetitive thinking patterns. Worry can be understood as a mental strategy to reduce uncertainty. In preparing our minds for the unknown, we anticipate and consider numerous possible results to avoid being caught off guard when a situation arises.

Unfortunately, instead of reducing our anxiety and worry regarding an outcome, the mental preparation causes us even greater anxiety and distress (Dugas et al., 2005). When uncertainty cannot be resolved, people may ruminate repeatedly, thinking about unanswered questions. Research shows that rumination maintains a negative mood, increases helplessness and reduces problem-solving ability. This cycle is especially strong in individuals with high IU (McEvoy & Mahoney, 2012).  

Individual Differences in Tolerance for Uncertainty  

Every person’s approach to an inability to manage adverse and uncertain conditions is unique. Psychological studies have identified several influencing factors.  

1. Personality Traits: Higher IU is associated with Neuroticism, Perfectionism, and low emotional regulation skills, whereas lower IU is linked with Cognitive Flexibility, Psychological Resilience, Open-mindedness and New Experiences. 
2. Individual learning and life experiences: Those growing up in volatile and unsafe environments will likely experience a heightened sensitivity towards uncertainty in their adult years due to their previous life experience with uncertainty being a genuine threat. 

Managing Uncertainty

The world is continually changing. From this continual change, there is a great deal of uncertainty. In general, the way that people handle uncertainty creates an increased level of stress. Whereas, for some people, their stress comes from the actual uncertainty they face. People who become intolerant of uncertainty often experience fear, struggle to make good decisions, and are unable to reach their full emotional well-being. Understanding the psychology behind uncertainty helps explain: Why anxiety is so common; Why do people avoid change; Why is there little to no lasting relief from Reassurance.

The ability for individuals to be able to tolerate uncertainty, instead of attempting to eliminate it, is the foundation for developing emotional resiliency and psychological flexibility. Cognitive-behavioural therapy (CBT) targets IU by:  

•  Challenging catastrophic interpretations of uncertainty, such as assuming “If I don’t  hear back from my employer today, I will definitely lose my job,” or “If I feel  anxious, something terrible must be about to happen”
• Reducing our use of reassurance-seeking behaviour  
• Encouraging gradual exposure to uncertain situations  

Research shows that reducing IU leads to improvements in both anxiety and mood disorders  (Shihata et al., 2016). 

Psychological research highlights strategies such as:  

• Accepting uncertainty as a normal part of life  
• Practising flexible thinking  
• Shifting focus from control to adaptability  

These approaches help individuals respond to uncertainty with curiosity rather than fear.

Learning to Live with Not Knowing 

Uncertainty is not something to eliminate, but an inherent aspect of life. While the human mind seeks predictability, psychology reminds us that complete certainty is impossible.  Attempts to remove uncertainty often increase anxiety rather than reduce it.  

One view of how to understand your anxiety and inability to make a decision is through Intolerance to Uncertainty. In essence, IU reminds us that we are unable to grow as people if we choose to remove uncertainty from our lives, but rather we must learn how to accept and cope with it. In accepting uncertainty, we do not lose control. We gain the freedom to respond with flexibility, resilience and insight. 

References + 

• Berenbaum, H., Thompson, R. J., & Bredemeier, K. (2020). Intolerance of uncertainty: Exploring its dimensionality and associations with need for cognitive closure, psychopathology, and emotional distress. Journal of Anxiety Disorders, 73,  102235. https://doi.org/10.1016/j.janxdis.2020.102235 

• Carleton, R. N. (2016). Fear of the unknown: One fear to rule them all? Journal of  Anxiety Disorders, 41, 5–21. https://doi.org/10.1016/j.janxdis.2016.03.011

• Dugas, M. J., Gagnon, F., Ladouceur, R., & Freeston, M. H. (2005). Generalised anxiety disorder: A preliminary test of a conceptual model. Behaviour Research and  Therapy, 43(2), 215–234. https://doi.org/10.1016/j.brat.2004.01.007 
• Ellsberg, D. (1961). Risk, ambiguity, and the brutal axioms. The Quarterly Journal of Economics, 75(4), 643–669. https://doi.org/10.2307/1884324 
• McEvoy, P. M., & Mahoney, A. E. J. (2012). To be sure, to be sure: Intolerance of uncertainty mediates symptoms of various anxiety disorders and depression. Behaviour Therapy, 43(3), 533–545. https://doi.org/10.1016/j.beth.2011.02.007 
• Morriss, J., Christakou, A., & van Reekum, C. M. (2022). Uncertainty makes me emotional: Effects of uncertainty on emotional responses. Frontiers in Psychology,  13, 777025. https://doi.org/10.3389/fpsyg.2022.777025 
• Rettie, H., & Daniels, J. (2021). Coping and tolerance of uncertainty: Predictors of mental health during the COVID-19 pandemic. BMC Psychology, 9, 75.  https://doi.org/10.1186/s40359-021-00589-4 
• Shihata, S., McEvoy, P. M., Mullan, B. A., & Carleton, R. N. (2016). Intolerance of uncertainty in emotional disorders: What uncertainties remain? Journal of Anxiety  Disorders, 41, 115–124. https://doi.org/10.1016/j.janxdis.2016.05.001