Background

One source of evidence for the corollary discharge theory comes from the movement of afterimages. If you look directly at a bright light and then close your eyes, you will see an afterimage of that light. When you move your eyes, the afterimage stays on the exact same part of the retina. However, you sense motion in the afterimage. Why is this the case, if the afterimage has not moved across your visual field? It must be because of feedback from a corollary discharge loop.

Use this activity to explore moving afterimages. You will stare at the center of a cricle to create the afterimage. When done, look around. What happens to where you see the afterimage?

Instructions

Full Screen Mode

To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.

Illustration Tab

Settings

Below is a list of the ways that you can alter the illustration. The settings include the following:

Start: start the adaptation. Look at the cross in the middle of the screen. One circle will be presented during adaptation. The screen will return to complete white when adaptation is finished. You can also start adaptation by touching or clicking the stimulus area.
Circle Size: how big is the circle you will adapt to.
Duration (sec): how long will adaptation last, in seconds.
Color Wheel: use the color wheels to pick color to adapt to. The color wheels change the color of the circle in the same relative position.
Background Level: the intensity level of the background.

Reset

Pressing this button restores the settings to their default values.