We used to think that if you can see pain coming, it’ll hurt more. A new study from the University of Tsukuba finds that the opposite is true: Unexpected events can make pain feel more intense.

Using virtual reality, participants saw a knife appearing to stab their arm while heat was applied to the same spot. When the knife suddenly vanished before contact, their reported pain levels increased, especially when the heat was delayed.

These findings challenge the idea that the brain reduces pain by correcting prediction errors.

Instead, they suggest that surprise amplifies pain, making unexpected sensations feel stronger. This could lead to new ways of managing pain, including virtual reality therapies and cognitive techniques that help control expectations.

More: The AI will see you now