One of the top social media items today regards the color of the above dress. Is it blue and black? Or white and gold? The internet is in a disarray and a great debate has ensued. Even Taylor Swift has chimed in (her vote is blue and black). I see white with a gold fringe.

Actually both answers can be correct. The phenomenon for why the dress can be both blue with black fringe and white with gold fringe can be easily settled using concepts from visual science and psychology. Building off of Carolyn’s post on how we see color, we have receptors in the back of our eye called the retina that are sensitive to specific wavelengths of light. This information then goes down the visual stream to the visual processing centers in the brain. This is where things get interesting. The “color” of the light that initially illuminates the object will be discounted in our brains such that we only perceive the reflected color of the object. A white shirt will look different at whether you are standing directly beneath the sun or under the shade, but we will still perceive it as white. That is, context is another factor that influences the colors we perceive. Similarly, items will have a yellow tint when viewed under incandescent light bulbs and a slight blue tint under florescent light bulbs but our visual system will subtract the information about the source of illumination. This phenomenon is known as “color constancy”–the perceived color of an object remains constant under different lighting conditions.

There are many color constancy illusions demonstrating that color is a subjective experience and not a reflection of objective reality. A classic example of color constancy is the same color illusion created by MIT vision scientist Edward Adelson.

A looks darker than B, but they are actually the same color (click here for the proof and explanation). Several cues create the perception that A is darker than B. 1. Source of illumination. It’s coming from the right corner and blocked by the green cylinder. The shadow would make B appear lighter. 2. Context. B is surrounded by dark squares and if there is a general pattern of alternating light and dark colored squares then B appears lighter than A.

Since we do not know the light source that was used to take the picture of the dress, our brains are uncertain about what hues to discount when perceiving the image and thus the debate! A tangible way to play with that is to change the brightness setting of your monitor and you can see how lighting can influence your color perception.

Lucky for us the internet is a wonderful source of information and people who actually saw the dress in person have confirmed that the dress is blue with black lace.