According to recent studies at the Universities of California and Chicago, language affects half of what we see. The researches base on the well known Sapir-Whorf hypothesis which states, that there is a relationship between our language and our experiences and thoughts.

The Sapir-Whorf hypothesis can be tracked back to the late 19th century and started a long and lasting debate about language-and-thought. This new results provide an unexpected resolution to the debate.

The studies are primaraly based on the following experiment: A circle of 12 squares is shown to the participants. All but one square have the same color, some shade of green. The odd square was either painted in another shade of green or in some shade of blue.

Before we have a look at the results let me point out two important things: First of all language function is processed predominantly in the left hemisphere of the brain. And secondly visual impressions from the right side are mostly handled on the lefthand side of the brain and vice versa.

The results of the experiment were as follows: If the odd square was on the right half of the visual field the participants reacted faster if the color had a different name (blue) than if it had the same color name (green). But notice this happened only on the right part of the visual field. The scientists say the reason to this is because language is also processed on the left side. Whenever the odd square was on the left half of the visual field no such factor could be measured.

Due to those experiment they concluded, that language affects vision, but only if it is processed on the same side as language function. Vision is therefore at the same time filtered and not filtered through language.

And what happens if we get on top of that color blindness into the game? People suffering from color blindness share the same language but have a different visual impression. Would they perform worse, better or just the same as people with no color vision deficiency?

Of course, if you can’t see the different shades it is not worth making the test. But if you can view them but can’t exactly tell, which is a shade of blue and which a shade of green. It would be very interesting to now the answer. Unfortunately they don’t make any statements about color blindness.

What do you think? Does language affect color vision when suffering from color blindness in the same way?

Original proceeding by Aubrey L. Gilbert, Terry Regier, Paul Kay, and Richard B. Ivry at Whorf hypothesis is supported in the right visual field but not the left (subscription required).

Further readings:
Language affects half of what we see
How we see half the world through the prism of language
Sapir-Whorf hypothesis

I call this Damn Interesting.

Damn Interesting is a very nice blog about damn interesting stuff. They post every day a new story about stuff everybody is eager to know. I found this site just a few days ago and subscribed to it immediately. And what happened some hours ago?

Cynthia Wood writes a post about A Life More Colorful which guides as behind the curtain of color blindness and tetrachromacy. Simply put colorblind people are dichromats (having two different color receptors), people with normal vision are trichromats (three different receptors) and well tetrachromats have four different receptors. Hard to imagine but they can tell apart even more colors. I as a red-green colorblind guy would say – very very hard to imagine.

I would say the people behind Damn Interesting really care about their readers. But go on and learn more about tetrachromats at A Life More Colorful.

Red-green color blindness is in the majority of cases provoked through a defective X-chromosome. Human beings have 23 different pairs of chromosomes whereof one pair is the so called sex-chromosome. This pair consists of two X-chromosomes on women and one X- coupled with one Y-chromosome on men. Color vision in the red-green area is coded on the X-chromosome which is called a sex linked trait.

This concludes if a man is a carrier of a defective X-chromosome he will suffer from color blindness. On women the not defective chromosome is in charge and therefore she is not colorblind but a carrier for color blindness. Because a women needs two defective X-chromosome to be affected this symptome is called X-linked recessive. A very interesting conclusion of this: If you are male and your father suffers from a red-green color vision deficiency you can not inherit it from him. Only women can be carriers for color blindness who pass it on to their sons.

Let’s have a look at some illustrations. On the left you can see how the disorder is passed on from an affected father to his children. The sons are unaffected and do not have the mutation. The daughters are not affected but are both carriers of the disorder because they inherited the defective X-chromosome from their father. The illustration on the right side shows a mother which is a carrier and a father which is unaffected. Their son is at a rate of 50% affected i.e. red-green colorblind and their daughter is at the same rate either are carrier or unaffected.

In the last illustration we coupled an affected man with a women which is a carrier. As you can see their children are at a rate of 50% affected. This is the only case shown here, where a women can be affected i.e. suffering from a red-green color blindness. If the children are unaffected the daughter is anyway a carrier of the disorder. The not shown combinations where man and women are either both affected or both unaffected are left to the reader…

I hope this could give a better insight into the biology behind color blindness. It has to be noted that these remarks are only true for red-green color blindness. Blue-yellow color blindness (tritanopia) is linked to the chromosome pair 7 and therefore sex independent. Further readings on this topic and more details can be found under the following links:

• Genetics Home Reference
• The Center for Genetics Education
• Wikipedia

The above illustrations are provided by the U.S. National Library of Medicine, 7^th March 2006.

If you are colorblind and are looking for a new job choose either hunter or soldier. According to the article “In Combat, Stick with the Colorblind” in the latest issue of Discover Magazin you could belong to the top in one of those prefessions. English scientist discovered that colorblind people are much better in distinguish different khaki colors. And out of that they concluded, that colorblind people make good hunters or soldiers. I never hunted but I was in the army, it’s compulsory in Switzerland. We were wearing those funny clown costumes and sometimes we were even digging through the mud. Personally I never thought I could make out my counterparts and just because of my color blindness I was definitely not a better soldier. The scientists even hypothesize that we colorblind are a revolutionary relic because we can spot predators or hidden food. This makes me feel good – being a bit closer to our ancestors and not only being handicapped but even have an advantage over the not colorblind under us.

In the words of my doctor:

[…] suffering a total color blindness with a very strong protanopia […]

And what does this mean? Wikipedia discribes the different kinds of color blindenss in detail. If I read through this article I’m not sure if I suffer just under protanopia or under deuteranomaly and protanopia. Hmmm. I remember he showed me many many circles in a thick book which was split in two parts. In the first part I could see on the first four pages the numbers (you have to recognize numbers inside the circles; they are shown in a different color). Then nothing. He browsed through at least 20 more pages and stopped again in the middle of the book. I look at it. Yes, I see the number and on the next page – nothing. And so on. Maybe the first part was for protanopia and the second for deuteranopia? I don’t know. Anyway, this was over 10 years ago. If I look these days at some example pictures I often can’t recognize any difference for both characteristics. So I would say I’m quite handicapped :-)