Eyesight is a remarkable thing, but it's also imperfect, which is exactly what optical illusions seek to take advantage of. In this one, you'll be able to trick your eyes into seeing a black and white image in full color.
Cone cells are one of the types of photoreceptor cells in the retina, of which most people have three subtypes that are each sensitive to either red, blue, or green light. They function well in stronger light and are responsible for our color vision, which is why discerning color becomes more difficult in low light, as rod cells (which only come in one variety) take over. It turns out that these cones can be "exhausted" in a sense; namely, if they are exposed to a certain color too intensely, they temporarily lose sensitivity, and vision skews toward the complementary color. To use this in an optical illusion, a researcher has a participant stare at an image with intense false color for a few seconds while the brain adapts. Then, the image suddenly flips back to black and white, but to the participant, it appears as a true color image before slowly adjusting back to normal. It's a neat trick that you can try for yourself in the above video!
[via IFLScience!]
I watched it a second time, covering the central dot throughout. Even so, I saw it in full color, albeit for a much shorter period. Very cool. Or disturbing, depending on your point of view. :-)
I'd be curious to know what role the dot plays.
It just keeps your view fixed so that the "exhaustion" of the cones is doesn't change.
So your eyes will expose the inverted colors evenly.
I noticed that I can keep the "full color" for quite a few seconds if I don't shift my view, but if I shift focus to another part of the image it instantly goes to black and white even if it's just half a second after the images are swapped.
That's exactly what happened to me! It's very neat.
I think the dot just serves as a focal point so your eyes don't move around, keeping the 'color' image around, longer.
That was fun ;-)
This isnt new information to the art field. As an art major, we were taught these optical illusions in color theory.