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Mind

This optical illusion expands as you stare at it - and now we know why

Using a computer model of the retina, researchers have been able to trace the cause of the expanding hole illusion

By Matthew Sparkes

24 January 2025

The expanding hole illusion seems to mess with your mind, but really your eyes are to blame

Akiyoshi Kitaoka, Ritsumeikan University, Japan

The optical illusion seen above makes the viewer feel as if they are falling into an expanding hole – and now we have a good explanation for why this happens.

Optical tricks can be caused by different elements of our visual and neural systems, even when the effects are similar. For example, the spinning circles of the Pinna-Brelstaff illusion are created by a communication delay between different regions of the brain that process vision. Meanwhile, another spinning circle illusion, …

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