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After the highly controversial, relationship dividing #TheDress photo emerged last Thursday, lots have asked how two people can see the same thing in different ways. Neuro-marketing expert, Professor Diana Derval, posted an interesting tutorial on the basics of vision to LinkedIn.  The test explains the variations in colors that different people see.

Derval says the amount of colors you see depend on the number and distribution of cones or color receptors in your eyes.

Take the test.  Count the colors you see in this spectrum:

How many colors do you see? Click the image to zoom. (
How many colors do you see? Click the image to zoom. (
  • See fewer than 20 color nuances: Derval says you’re a dichromat. 25% of the population are dichromats. Also, dogs are dichromats. Dervals says dichromats likely wear black, beige and blue.
  • See between 20 and 32 color nuances: You’re a trichromat. That means you have 3 types of cones. Dervals says trichromats enjoy different colors and can appreciate them. About 50% of the population is a trichromat.
  • See between 32 and 39 colors nuances: You’re a tetrachromat. Dervals says these people have 4 types of cones. They also get irritated by yellow and will most likely never wear it. About 25% of the population is a tetrachromat.

If you see more than 39 colors nuances — you are making things up. Dervals says there are only 39 different colors in the test above and probably only 35 are properly translated by the computer screen.