Motion Induced Blindness | Illusions

Motion Induced Blindness

Written by Justin Whelan

What to see

On the right you see a rotating array of blue crosses and 3 yellow dots. Now fixate on the centre (watch the flashing green spot). Note that the yellow spots disappear once in a while: singly, in pairs or all three simultaneously. In reality, the 3 yellow spots are continuously present, honest!

What to do

You can use the slower/faster buttons to change speed. Disappearance persists down to surprisingly low speeds.

You can use the larger/smaller buttons to change size. Disappearance persists up to surprisingly large sizes.

You change the colour of the rotating crosses, the dots and the background. The dots disappear into whatever colour the background has.

The “grating on/off” button allows to observe the filling-in process more closely: when the grid is visible, it continues through the vanishing yellow dots.

The ‘defaults’ button at the top restores the standard settings.

Comment

Steady fixation favours disappearance, blinks or gaze shifts induce reappearance. All in all reminiscent of the Troxler effect, but stronger and more resistant to residual eye movements.

An interesting fact was mentioned by Pete in the guestbook: “If you stare at one of the yellow dots, even the center (green) dot will seem to change to yellow.” Yes, I agree, and quite unexpected.

In all likelihood, the motion is not necessary. Any change in the image will suffice.

Source

Bonneh, Cooperman & Sagi (2001) Motion-induced blindness in normal observers. Nature 411:798–801

Thanks to Jürgen Krüger for coaxing me into adding more interactivity

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