Illusory Neon Heart

Notice that the yellow fields inside of the heart appear paler than the fields forming the contour of the heart, which appear to be a darker shade of yellow/orange. Right? Wrong. Actually, all of the yellow fields in the figure are identical. Any differences that you see are all in your mind. This effect is called “neon color spreading,” because it resembles the effect of the light spreading from a neon lamp. The neuralunderpinnings of this effect are not yet understood.