Did you think the "dress" was white and gold? You may not have the fourth cone in your eye. Professor Diana Derval, author of  "Designing Luxury Brands: The Science of Pleasing Customers’ Senses," created this test to see how people perceive color. How many colors do you see in the above bar? 

Derval explains the following in her last book, "The Right Sensory Mix:  Targeting Consumer Product Development Scientifically." 

If you see fewer than 20 color nuances, you only have two cones. Your vision is similar to a dog's, which means you are drawn to black, beige and blue. A quarter of the population is dichromat (a person having two cones).

If you see 20 to 32 color nuances, you are a trichromat with three cones and see well in the purple, blue, green and red areas. Trichromats make up half the population. 

But if you see between 33 and 39 colors, you are a tetrochromat with four cones, which means you see purple, blue, green, red and yellow areas well. Tetrochromats make up the remaining quarter of the population. 

 

Do you see more than 39 colors? That would make you a bluffer. There are only 39 different colors on the test, and Derval says on computer screens, it may appear to be only 35 colors. 

What does this all have to do with the dress? Derval says tetrochromats are unlikely to get fooled by the lighting of the photo, and know that the dress is black and blue. Interesting, 68 percent of readers said the dress was white and gold in a BuzzFeed poll - not too far off from the 75 percent of non-tetrochromats out there.