Locomotion Prior 🟡 Medium
Expanding Hole
A completely static radial gradient black hole that appears to expand toward you as you stare at it.
⚠️ WARNING: THIS IMAGE IS COMPLETELY STATIC
Use the controllers inside the display card to interact with the visual triggers.
Use the controllers inside the display card to interact with the visual triggers.
🎮 EXPERIENCE IT FIRST
Before reading the neuroscience explanation below, take a moment to interact with the demo above:
- How does the visual change when you move your eyes or look at different parts of the screen?
- Use the slider or toggle buttons to reveal the actual geometric layout. Did it match what your eyes predicted?
- Pay attention to whether you can consciously force your brain to switch between interpretations.
🧠 THE SCIENCE
The Expanding Hole is a newly discovered illusion that demonstrates how predictive coding triggers physical, involuntary physiological changes in our eyes. The image is completely static, containing a dark central circle with a soft radial gradient on a dotted background. Yet, when you stare at it, the dark hole appears to expand as if you are moving into a dark tunnel. Your visual cortex does not just passive-record light; it actively predicts changes in your environment (predictive coding). The radial gradient simulates entering a dark space. To prepare for this lack of light, your autonomic nervous system triggers pupillary dilation, expanding your pupils. This physical change alters the amount of light entering your eye, which your brain interprets as the dark circle physically expanding.
💡 FUN FACTS
- • Published in 2022 by researchers at the University of Oslo, it is one of the newest famous illusions.
- • Eye-tracking cameras confirmed that 86% of observers experience physical pupillary dilation when looking at the dark hole.
- • The illusion fails if the central hole is colored (e.g., green or red), as colored holes do not imply a drop in light levels.
- • It proves that the brain's prediction of light levels can trigger involuntary physiological responses.
🧪 TRY THIS AT HOME
Stand in front of a mirror in a well-lit room. Stare at a printout of the expanding hole for 10 seconds, then look quickly at your pupils in the mirror. You will see them briefly contract as they adjust back from the dilation triggered by the illusion!
📜 WHO DISCOVERED IT
Discoverer: Bruno Laeng (2022)
Bruno Laeng, a professor of psychology at the University of Oslo, was investigating how visual patterns trigger pupil reactions. He designed this radial gradient pattern and discovered that it could physically trick the pupils into dilating, proving that visual perception is highly predictive.
Educational Resources & History
Expanding Hole optical illusion pupil dilation science. Learn about the 2022 University of Oslo discovery, how predictive coding triggers autonomic pupillary dilation, and play with our interactive expanding gradient widget.