Optical Illusions Revealed

http://brainden.com/color-illusions.htm

After our discussion with Prof. Bevil Conway in class about the various optical illusions like that of the famous dress and the Rubik’s cube, I was intrigued and wanted to experience some more optical illusions firsthand. I came across a very interesting phenomenon, that combines both light and motion. It is the phenomenon of the Lilac Chaser, more scientifically known as Troxler’s fading. In the link attached above, if you concentrate on the black cross at the center of the circle long enough, the moving lilac dots turns green.

The effect results from our visual neurons switching off their awareness of things that aren’t changing, and increasing their perception of things that are. The lilac dots stays still while the absence of the dots moves. Thus, after a brief figuring-out period, the visual system transitions to focusing on only the moving blank dots which it turns green because of a second illusion at play here and lets the immobile lilac dots fade. Further, these is another optical illusion in it as well. As for the other optical illusion, the blank dot turns minty green because your retina has been over saturated with the lilac colored dots. When the lilac is removed from the spots, you see its complementary color (minty green) instead, which is composed of white light minus the lilac.

It was intriguing how my understanding of these optical illusions had transformed as I was now better able to understand and explain the underlying scientific phenomenon for what I was observing.