Uncertainty Intensifies Pain, Study Reveals

A new study from Aarhus University’s Department of Clinical Medicine has found that the brain interprets pain more intensely when it doesn’t know what to expect, even if there’s no actual physical harm. This research, published in Science Advances, sheds light on how uncertainty can amplify pain perception.

The study explored the “thermal grill illusion,” a phenomenon where simultaneous warm and cold stimuli create a sensation of burning pain. Researchers, led by Associate Professor Francesca Fardo, designed an experiment where participants predicted whether they would feel warm or cold sensations on their forearms. However, sometimes participants were exposed to both warm and cold stimuli at the same time.

“Previous research has shown that our expectations shape how we experience pain,” Fardo explained. “In this study, we wanted to find out whether uncertainty in those expectations, or when the brain doesn’t have a clear prediction, could also increase the pain. By taking advantage of the curious case of the thermal grill illusion, we could show that even when nothing harmful is happening, not knowing what to expect somehow makes us feel a fairly high level of pain.”

The researchers used brain imaging and computer modeling on 300 participants to observe how uncertainty responses correlated with specific brain regions. The results indicated that uncertainty, not just expectation, plays a significant role in pain perception.

“Our results show that uncertainty, not just expectation, plays an important role in pain,” Fardo stated. “Previous research on placebo and nocebo effects has shown that expecting relief can reduce pain, while expecting harm can make pain worse. Our findings add a new layer: when the brain is unsure about what to expect and encounters ambiguous signals, it errs on the side of caution, intensifying pain beyond what’s necessary.”

This discovery may have implications for pain management and the treatment of anxious patients. Providing clearer information and setting precise expectations could potentially reduce uncertainty and lessen perceived pain.

Fardo plans to conduct further studies on individuals with chronic pain, investigating the role of psychological factors like depression and anxiety in pain perception.

Key Findings:

• Uncertainty about expected sensations intensifies pain.
• The brain’s response to uncertainty can amplify pain beyond actual physical harm.
• Clearer information and precise expectations could improve pain management.
• This study used the thermal grill illusion to understand the effects of uncertainty on pain.
• Brain imaging and computational modeling were used in this study.

Reference:

• Jesper Fischer Ehmsen et al, Thermosensory predictive coding underpins an illusion of pain, Science Advances (2025). DOI: 10.1126/sciadv.adq0261

Disclaimer: This news article is based on the provided information and should not be taken as medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.¹ The findings of this study represent a snapshot of current research and further investigations may yield different results.