A few days ago the internet went to war over the color of a blue dress. While the entire discussion might seem trivial, the dress is actually a good illustration of how your eyes work, how your mind works and how they sometimes fail to work quite right.

So while the world has mostly moved on from arguments over the dress color, scientists, color researchers and photo editors have all taken up the question of what exactly was going on with the photo that managed to fool so many people.

Like most optical illusions it takes advantage of the way your mind works and allows you to trick yourself. For example, film and work by taking a large number of still images and showing them too you so quickly that they blur together and give the appearance of movement. The Rubin face/vase illusion, which causes people to see either two faces looking at each other or a vase, is yet another famous example.

That example is actually somewhat relevant because it demonstrates the difference between vision and perception. In other words, it forces your brain to fill in information that your eyes don’t make clear.

“The observer’s “perceptual set” and individual interests can also bias the situation. Biasing the shapes or contours can make one interpretation stronger than the other one. As one can see in the three-dimensional model of the vase, which biases the vase,” says the website of the the Department of Psychology at the TU Dresden.

In the case of the dress there are a few different tricks being played. One of them, say the makers of ASAPScience, is that it forces the user to guess at context.

We all know that colors can appear differently depending on the lighting, the time of day and the amount of shadow. However in the picture of the dress, none of this information is provided. However the human mind, being the supercomputer that it is, will attempt to fill in all of this information anyway.

“What’s happening here is your visual system is looking at this thing, and you’re trying to discount the chromatic bias of the daylight axis. So people either discount the blue side, in which case they end up seeing white and gold, or discount the gold side, in which case they end up with blue and black,” Bevil Conway, a neuroscientist who studies color and vision at Wellesley College, told Wired.

That, however is only part of the trick. Conway also said that when he originally looked at the image he saw blue and orange and that reveals another part of the trick. The dress is definitely blue but it’s a very golden blue.

The Red-Green-Blue (RGB) values for the particular blue are R 93, G 76, B 50. With that much red, you would expect the color to be in the orange spectrum rather than the blue.

According to Conway “…you’re doing this very bad trick, which is projecting those patches on a white background. Show that same patch on a neutral black background and I bet it would appear orange.”

So your mind, given limited information and trying to fill in the blanks is given “orange” as a clue.

Neil Harris, senior photo editor at Wired, was initially fooled as well.

“I initially thought it was white and gold. When I attempted to white-balance the image based on that idea, though, it didn’t make any sense. It became clear that the appropriate point in the image to balance from is the black point,” said Harris.

The psychology department of the University of Massachusetts, Lowell has a nice gallery of optical illusions for those who would like to better understand how the mind works and sometimes fails to or for those who are looking for something new to argue about now that the dress is blue.