The internet is losing its collective shit over the color of this dress. It is, as most internet rows, a solved problem.
Some people see a blue and black dress, others see a white and gold dress. The truth is that this is clearly a terrible photograph that contain none of the above colors and your brain is lying to you.
In case you do not believe me, for some absurd reason, I have also included the same image with the colors sampled as swatches. Note the distinct lack of black, gold or white. The image is shades of faded blue, violet and brown.
So why are people seeing different colors. The solution that seems most likely that it is a variant on the checker shadow illusion that most of us are familiar with. The trick of the shadow convinces our brain, in no uncertain terms, that A and B are different colors.
The major difference is that in the above illusion, we can see the shadow, and in the image we have to work backwards from what we can see to sort out the lighting.
Our brain autocorrects for lighting. Most painters out there learn this pretty quickly, especially when painting landscapes. Trees are not brown, snow is not white, grass is not green. Depending on the lighting they can be any number of hues. Our brains learn these rules really young and work out how to determine the “actual” color of something based on the lighting.
Problems arise when the lighting is ambiguous, though, as in that photo. Is that a dress the is overexposed and front lit? In which case it is blue and black, or a dress that is backlit, nearly in silhouette? Which would mean it is gold and white.
Let me try to exaggerate the effect
The actual dress was found on amazon and it is very clearly blue and black.
*This came up as a key result when I searched for “overexposed photo” I had to use it.
*Edit, XKCD did a better job than me with the image comparison, using