What Do We Really See?
By: Gabrielle Toutin,
Staff Writer
When I say “yellow”, you think of yellow and about things that are yellow. The sun, fall leaves, and such. But does your definition of yellow match mine? When I see what I call yellow, do you see what I call blue, but you call it yellow? Or do you see exactly what I see as yellow? The answer to these questions lies in the setup of the human visual system and the human brain.
Humans have three kinds of color sensing photoreceptors. One kind senses blue, one kind senses green, and one kind senses red. Photoreceptors translate colors into electrical signals the brain can understand.
Some humans can sense color better than others. Color-blind people usually are not very sensitive in their green photoreceptors. 1 out of 12 men and 1 out of 255 women are colorblind.
On the other hand, tetrachromats can see more colors than the average human. This happens because tetrachromats have four kinds of cones instead of three. They have blue-sensing cones, green-sensing cones, red-sensing cones, and a mutated cone that enhances color perception. Women are more likely to be tetrachromats because the gene that controls cone cell pigments lies on the X chromosome and women have two X chromosomes and men have one X chromosome and one Y chromosome. This is also why more men than women are colorblind.
There are tests to determine if a person is a tetrachromat. This test shows three circles. Normal-sighted people see from left to right: a red circle, a yellow circle, and a green circle. However, tetrachromats will be able to see images inside the circles. Please comment if you are able to see these images; tetrachromats are rare.
There are also tests to determine if a person is colorblind. This test shows a rectangle of dots. The dots are colored differently. People with normal vision will be able to see a picture of a form of transportation formed by the differently colored dots. Colorblind people will not see any picture.
Human vision is a tricky part of biology. However, advances in biology may give blind or colorblind people the ability to see properly or even above normal. Imagine a future where vision issues no longer existed. This may be where humankind is headed.
Bibliography
Greenwood, Veronique. "November 2014." Discover Magazine. N.p., n.d. Web. 24 Oct. 2014. <http://discovermagazine.com/2012/jul-aug/06-humans-with-super-human-vision>.
"Online Color Challenge." Color Test -. N.p., n.d. Web. 24 Oct. 2014. <http://www.xrite.com/online-color-test-challenge>.
Stafford, Tom. "Do we all see the same colours?." BBC Future. N.p., n.d. Web. 24 Oct. 2014. <http://www.bbc.com/future/story/20120209-do-we-all-see-the-same-colours>.
"Tetrachromacy in Humans: You May Have Super Color Vision." Color + Design Blog / by COLOURlovers. N.p., n.d. Web. 24 Oct. 2014. <http://www.colourlovers.com/blog/2010/03/18/tetrachromacy-in-humans-you-may-have-super-color-vision>.