The question is, what do you mean by "correctly"? When we look at the Checker Shadow Illusion, our brains are automatically "parsing" that image into a 3D scen

The question is, what do you mean by "correctly"? When we look at the Checker Shadow Illusion, our brains are automatically "parsing" that image into a 3D scene and compensating for the lighting and shadowing. The reason you see square B as being lighter than A is because, if you could reach into the image and remove the cylinder so it's not casting a shadow anymore, square B would be lighter than A. Our brain doesn't think about color in terms of absolute hex values. Instead it tries to compensate for the lighting and positioning of elements, assuming that they're similar to what we would see in real life—a challenge which, by the way, computer vision systems have always struggled with. That sounds pretty "correct" to me.