My dad sent me this link. It’s pretty cool, and one of the few cases where he can relate part of his work (as a color scientist) to something I can understand.
The colored image that you stare at has the color chroma data reversed. When you bring the mouse into the field you will suddenly see a full color image appear, and then fade to B&W as your eyes adapt to black and white image. The color you see for a short instant is based upon the eye locally adapting to the previous negative color image.