Where Is Colour?

Giuliana Mazzonia

University of Hull, UK

At the moment, the therapy has only been fully tested on animals, but the results of initial clinical trials in humans suggest that it might be extended to pathological conditions in human colour vision in the relatively near future. Let's imagine what it would be like for a person suffering from colour blindness who undergoes this gene therapy and recovers colour vision.

1.1 A SUCCESSFUL STORY FROM THE FUTURE

"As I was walking to the train station this morning, I noticed the colours of the leaves on the deciduous trees around the house — gold, bright yellow, pale green, deep red. Beautiful. But, 'where is colour?' I was asking myself. The question comes from my own experience as someone who used to be colour blind. That's right, colour blindness can be corrected. In the beginning, my eyes did not work properly, but after a new rather revolutionary surgical intervention, I could see colours as they appear in the external world to other members of my species. What an experience!

My form of colour blindness is called achromatopsia and it is rather rare. You see, it turns out that most colour blind people do actually see some colour. What's more, there are various forms of colour blindness; some can see a couple of colours, although somewhat dull, others can see much less colour than most. Fancy names are associated with these various forms of pathology. For example, dichromats (mostly men) can see only two ranges of colour and, among those, deuteranopes present problems discriminating between red and green while others with protoanopia cannot see red and similar hues, those with tritanopia fail to discriminate blue hues. Other people can only see one colour, monochromats. Finally, there are people like me, who have complete color blindness, otherwise known as achromatopsia. People of my (original) disposition are completely colour blind, like the inhabitants of the remote island (the Micronesian atolls of Pingelap and Pohnpei) described by Oliver Sacks. Apparently, they also see the world the way I saw it, in shades of grey. I was the one in 40 000 born that year with achrmatopsia: 39 999 with good vision, and me. But all that has changed now, I can finally see colour.

Yet, a question occurred to me in my current state: Now that I see the colour of the leaves, does it mean that leaves really have colour? Which was the version of the world closest to the truth: is the world coloured? Or is colour just in the eye and the brain of the beholder? Before surgery, my world was mostly monochromatic. It is a rather strange experience to recover colour vision, especially at the beginning, when colour patches do not match the shape of the objects to which they are supposed to belong. I could see the shape of my car, but the red was floating somewhere near to it, and at first it did not 'stay' within the car shape. It was when I was recovering, and seeing those coloured patches outside of the objects they were supposed to belong to, that I wondered if colours do indeed exist in the external world, or whether they are only 'in the mind of the beholder'.

In some cases achromatopsia is determined by cerebral damage to areas in the occipital lobes, mostly an area called V4 (for visual) and specifically the lingual and fusiform gyri. Others, like mine are a special condition, in which little cells in the retina — called cones — were not working, while the brain was still intact. While most people think about the retina as simply a part of the eye, it is actually a part of the brain that was placed at the bottom of the eye. When all is going well, cones convert the electromagnetic waves of light sensory stimulus into electrical neural impulses.

Going back to my pathology, my cones were not working, because they were missing crucial proteins — opsins. These proteins react to specific light wave lengths and make colour visible. Without these opsins within the cones, there is no colour vision.

During surgery, genes that coded for the opsin proteins were artificially inserted into my cones giving my vision the range of colour that most people enjoy, more or less. The surgery was rather scary, but it had been successfully tested on our genetic cousins — other primates — before me, and had undergone some initial clinical trials on humans, so I was hopeful. It is a form of gene therapy and I am certain many more people in a similar condition as mine will volunteer to have it done. I will talk about the surgery later, but the core of my question remains, where is colour? Is it in the objects that we see, or is it in our eyes, or in the brain?

Living with colour blindness is not easy. A person who can see in colour cannot understand enough what colour brings. For example, there are emotional reactions innately connected to colour. Males seem to respond better to blue, females to red. Now, just to be clear, this doesn't explain why blue is sometimes associated with boys and why girls are associated with pink! That's a whole different ball game in sociological research. Nevertheless, even some forms of therapy are based on the realisation that different colours elicit different emotions in different people, even if some research suggests that specific emotions are elicited by specific colours in everybody (e.g. orange elicits friendliness, red excitement, green peace, etc). Also, people seem to respond to colour when making a purchase (does it mean advertisement and marketing strategies had no effect on me?) and colour responses can often play a big part in how our commercial world is seen. Curiously, the reason why Facebook's design is mostly blue is not because it was made by boys, but because its founder Mark Zuckerberg is red-green colourblind and can see blue best. Facebook apart, colour affects people's purchasing decisions, and marketing companies base brand colours on existing research in order to endear people to their products. Research made by companies has shown that specific colours are associated with specific attributions of product characteristics. For example, black is found to be associated with the idea of stability, credibility, strength, power, professionalism, accuracy; green with natural, organic, education, adventurous, calming; blue with cleanliness, medical, professional, judicial, business-like. Hence, to substantially simplify matters, black is good for solid corporations, green for ecological business and tourism, blue for medicine and science, etc. I looked at the website, https://blog.kissmetrics.com/color-psychology and indeed label colours convey — even to me — different impressions and emotions.

Typically, we also respond differently to pills of different colour. For...