Harvard Vision Lab created a few experiments that feature Attention Controls Errors and Perceptual Blindness. Below is one of their optical illusions.

Directions: concentrate on the central white dot.

Did the colors of the outside dots continue to shift throughout the video? If they stopped when the dots were rotating, then you’ve just experienced Silencing—the lab’s vocabulary for individual’s inability to pay attention to both motion and color shift at the same time. Here, we mostly call it Perceptual Blindness.

My Personal Experience with this Illusion: The first time I watched the video, I think the colors stopped shifting…but I don’t really remember—I wasn’t paying attention! The second time, I saw the shift. When I showed the illusion to a colorblind individual, he saw the shift from the first viewing.

To read about the complete experiment and to view more illusion videos, please visit the lab: http://visionlab.harvard.edu/silencing/