Dress Color
Dress Color
[Two images of a woman in a dress on each side of an image of a close up of a real dress with the same colors. On the left, she is colored blue on a dark blue background, while on the right, she is brown against a white background. Her dress is the same color in each panel - the same as the real one in between.]

This comic shows two drawings of a woman wearing the same dress, but with different background (and body) colors. The two drawings are split with a narrow vertical portion of an image from the web.
The comic strip refers to a dress whose image went viral on Tumblr only hours before the strip was posted and soon showed up also on Reddit , Twitter , Wired and on The New York Times .
Due to the dress's particular color scheme and the exposure of the photo, it forms an optical illusion causing viewers to disagree on what color the dress actually seems to be. The xkcd strip sandwiches a cropped segment of the photographed dress between two drawings which use the colors from the image against different backgrounds, leading the eye to interpret the white balance differently, demonstrating how the dress can appear different colors depending on context and the viewer's previous experiences.
Both dresses have exactly the same colors actually:
Below is an illustration demonstrating that the "colors" of the dresses are the same by connecting them with two lines with the above-mentioned colors (all the way!) and another which has one side flipped and merged into the other:

Similar types of illusions can be seen at Wikipedia's optical illusion page and for instance here at echalk (the latter page requires Flash®player).
This image has sparked surprisingly heated debate in many internet communities. A select few individuals may have prior experience with optical illusions of this ilk, but because this particular image went viral - it got heavy exposure over such a short amount of time - it reached millions of people who aren't so familiar with these sorts of mind tricks. To the uninitiated, the color of the dress seems immediately obvious; when others cannot see it their way, it can be a surreal (even uncomfortable) experience.
As an aside, the retailer Roman Originals would later confirm the dress was blue with black lace , and that a white dress with gold lace was not offered among the clothing line.
The title text refers to the game show Let's Make a Deal , hosted by Monty Hall, which was famous for having contestants pick among several doors which either had a real prize (for example, a car) or a joke prize (for example, a goat). Randall states that people find the dress color issue just as baffling as if upon opening the chosen door no one can agree if the item behind the door is a car or a goat. This is a reference to what has become known as the " Monty Hall problem :" if there are two goats and a prize behind three doors, the contestant has chosen a door, and one of the unchosen doors is opened to reveal a goat, should the contestant change his/her choice? Statistically, the answer is yes, but many people find this counterintuitive; discussion of this problem in Parade magazine touched off public outrage similar to the viral dress image.
Randall is presumably pointing out how ridiculous it is for people who don't understand the underlying science to become so adamant in defending their beliefs. A spoof of the "Monty Hall problem" previously appeared in 1282: Monty Hall , where Beret Guy decides to take the goat.
[Two images of a woman in a dress on each side of an image of a close up of a real dress with the same colors. On the left, she is colored blue on a dark blue background, while on the right, she is brown against a white background. Her dress is the same color in each panel - the same as the real one in between.]
