ag (fig. 3) on the last page of this report. When you stare at the black stars, your black-sensitive cells start to grow tired and lose their sensitivity. So, when you shift your gaze suddenly to a plain white background, you see white minus black where the black-sensitive cells have become fatigued. White light minus black light is white light. That's why the after image you see is white stars. The same thing happens when you stare at the turquoise and yellow because the complimentary color of turquoise is red, and the complimentary color of yellow is blue.After-imaging is also explained in Eric Haseltine’s article about mental fatigue on page 128 in the December 1999 issue of Discover Magazine. He states that while you were staring at the black, cyan, and yellow flag a battle was raging between the neurons in your brain that sense yellow and blue and the ones that sense turquoise and red. On the blank sheet, you should see an afterimage of the colors of the American flag. The suppressed blue and red activity, which was kept at a minimum as you looked at the flag, now dominates, and those are the colors you see on the blank sheet (Haseltine 1999). The interval that is required for the illusion to vanish corresponds roughly to the rallying time of the neurons used to see yellow and turquoise (Haseltine 1999).Throughout the years, many researchers have learned about the way in which we perceive the world through countless experiments with the systematic way in which we misperceive the world (Kassin 1998). We are surrounded by perceptual illusions (Wade, 1990; Rodgers, 1998). I hope that the examples that have been illustrated in this report will help you to better understand the world of perceptual illusions. Seeing should not always be believing....
