WHAT’S HAPPENING & WHY

In peripheral drift illusions, factors of luminance and contrast combine to create the appearance of motion where there is none. In this one, the light and dark shades next to each other make the colors slide in your vision, so the circles tend to “rotate” from dark to light. Some circles seem to rotate to the left and others to the right, based on the sequence of colors.^*

* Kitaoka A, Ashida H. Phenomenal characteristics of the peripheral drift illusion. Vision. 2003;15(4):261-262.

* http://www.ritsumei.ac.jp/~akitaoka/index-e.html