Change Blindness

This demonstration presents two nearly identical images that alternate with one small change between them. Observers often take a long time to notice the difference, highlighting the limits of visual attention and the phenomenon known as change blindness.

1. Display an image to participants.
2. Replace it with a nearly identical image that has one small alteration.
3. Continue alternating the two images in a loop.
4. Ask participants to identify the change.
5. After participants notice the difference, point out how it becomes obvious once detected.

Gradual change blindness - Michael Cohen:

Why You Miss Big Changes Right Before Your Eyes - NOVA:

📄 Change Blindness: https://sites.socsci.uci.edu/~ddhoff/cb.html

• Use photographs of real-world scenes instead of drawings.
• Introduce a blank screen between image transitions to increase difficulty.
• Test multiple participants and record how long it takes each to notice the change.

• No specific safety precautions required for this demonstration.

• Why does it take so long to notice the change? (Because our attention is limited, and we do not construct detailed representations of the entire visual scene.)
• Once you find the change, why does it become obvious every time? (Because attention is now directed toward that part of the image, making the difference stand out.)
• What does this suggest about how our brain processes visual information? (It suggests that we rely on selective attention rather than storing detailed representations of the whole scene.)