Fixate on the red blinking point in the center, while focusing you attention on yellow circles. Soon you should notice that occasionally some (or even all) yellow dots dissappear for a short period of time.

What is going on?

As soon as you move your eyes, you will discover that dots are still on the screen (and they always been there!). They only disappear from your perception. But why does a rotating grid makes yellow dots disappear? In a nutshell, a static dot on top of the rotating grid appears to be “out-of-place” and is discarded by your visual system as an errorneous signal. Scientists are still debating what kind of error the yellow dots correspond to. Some think it looks like a “motion streak” (the blurred swoosh you see behind your hand, then you wave it fast in front of your eyes). Others suggest that the lack of motion may signal your brain that there is problem with your vision at this location. In both cases, visual system tries to use information around that spot to “fill it in”, making you see surronding motion instead of the yellow static dot.

You can make your visual system to take yellow dots more seriously by making them bigger or putting a protection zone around them to keep the motion away. Or, you can make them blink: now they really disappear!

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