I never really understood the debate. In reality, if you were standing in front of the dress it is black and blue. Now, if you take a digital photo of the dress and post it on the internet as a terribly compressed jpg, with weird white balancing, and brightness/contrast turned up and down it is gold and white. The debate isn't really about the reality of the color of the dress but the reality of a badly edited photo.
I agree. But my wife was so firmly in the white/gold camp that I had to find this (and a better image of the actual dress, which is indeed blue and black) to help us understand one another’s perspective.
It's because we're also very used to seeing photographs of a subject in shade while the background is in full sunlight. If you take a picture of a white and gold dress in the shadow of a patio, with the background all fully lit by bright sunlight, the actual pixels representing white objects in the shade would be that bluish gray tint.
The problem here is that the dress isn't in the shade but those of us who see white and gold simply assume that it is in shade, while black/blue viewers (correctly) assume that it is under the same lighting conditions of the overexposed background.
This thread has been helpful for understanding how others could see it as white and gold; I never realized people were actually seeing it as in shadow even given the context of the rest of the picture.