This fascinating test helps you find out how many colours you can see
It's become apparent that the ability to see various colours varies widely from person to person. The reason for this stems from differences in the number of cone cells each of us has inside our eyes. These cells function as photoreceptors; the number you have affects how many colours of the visible light spectrum you can pick out.
The simple test published below was created by Professor Diana Derval. Answer the question and then check the answers, and you'll be able to find out how well you see the world around you - and how much your perception differs from other people.
Count the number of colours and shades you can see in the spectrum:
If you see...
Less than 20 colours: You're a dichromat. This means that you have only two types of cone cells. 'However, don't worry - you're in good company here, since dogs have exactly the same kind of vision', jokes Professor Derval. Perhaps you like to wear black, beige or dark blue coloured-clothing most of all. Twenty-five percent of the world's population are dichromats.
Between 20 and 33 colours: You have trichromatic vision. This means your eyes have three types of cone cells. You are able to perceive purple, dark blue, green and red colours well. This is great - 50% of the world's population have the same kind of vision as you.
Between 34 and 39 colours: Wow! You have tetrachromatic vision. Much like bees, you possess four different kinds of cone cells in your eyes and see the majority of colours in the visible light spectrum. The chances are you're not a fan of yellow and you have next to no yellow clothing in your wardrobe. Only 25% of people can see all the colours in the spectrum.
It's always interesting to compare your results with friends. Perhaps you've been close to a tetrachromatic person all your life and have never known just how special they are!