Expanding the Umwelt: Seeing A New Color in the Rainbow
Arthur Schopenhauer once said, “The World is my Idea,” but for those of us lacking the ego to leap directly to solipsism, the natural question to ask is “where did this idea come from?” Regardless of one’s stance on the identity or non-identity of the mind with the brain, it is reasonable to suppose that this idea comes from a combination of the collected and crystallized experiences of our ancestors embodied as the species-specific architecture of our brains; and the ever-changing, dynamic, adaptive plasticity of our neural tissue as it learns, remembers, experiences, and takes its unique shape that identifies it as a particular person in response to the prods and pokes of the random vicissitudes that sum together to make a life.
If we accept this premise, we may ask what conditions allow our brains to learn and change and have these experiences. How do we come to know about the World? Modern neuroscience tells us that this information is acquired by specialized sensory neurons, each adapted to detect specific sorts of energy from the world. Hair cells in the ear detect pressure waves in the air through the mechanical pulling of tip links, the action of which pulls open ion channels to depolarize the cell, thereby sending action potentials up through the network to the brain where we register this information as a perception. Touch receptors in the skin act in a similar fashion. Smell receptors in the nose and taste receptors on the tongue become activated when detecting the unique shapes of volatile molecules; perceptions in these modalities arise from combinatorial patterns of different activated receptors. Possibly the most interesting receptors of them all are the light-sensitive cells of the retina that allow the perception of color. Of three types in primates: red, yellow, and blue — or long, medium and short. They respond most strongly to their preferred wavelength, though they will be activated by a range of wavelengths that overlap. That is, in normal color vision, long wavelengths (reds) would strongly activate L-opsin cells while weakly activating M-opsin cells and not activate S-opsin cells at all. Medium wavelengths would likewise strongly activate M-opsins.
The color percepts are constructed, in a fairly complicated way, from the activation of various ganglion cells in the retina that measure the differential activation of the different kinds of receptors.
In the early 20th century Jacob von Uexküll generalized the concept of the World as Idea by introducing the idea of the Umwelt. As he explained it, Umwelt is the subjective bubble that surrounds each different organism. It depends on their sensory apparatuses, what they must do with their sensations (find their specific kinds of food, find mates of the same species, avoid their unique predators, etc.). Uexküll writes eloquently, even in translation, about how to conceive the Umwelt, for example, here his description of the world of the tick, written in 1934: “The eyeless tick is directed to this watchtower [a blade of grass or twig] by a general photosensitivity of her skin. The approaching prey is revealed to the blind and deaf highway woman by her sense of smell. The odor of butyric acid that emanates from the skin glands of all mammals acts on the tick as a signal to leave her watchtower and hurl herself downwards. If, in so doing, she lands on something warm — a fine sense of temperature betrays this to her — she has reached her prey, the warm-blooded creature. It only remains for her to find a hairless spot. There she burrows deep into the skin of her prey, and slowly pumps herself full of warm blood.”
Thus, the Umwelt of the tick consists of the presence and concentration of the odor of butyric acid, the temperature, and the feeling or lack thereof of hairy patch of mammal. Humans can experience any of these features of the tick’s Umwelt because we have sensory apparatuses that can be activated by the same features of the environment, though their meaning is totally different to us. With other animals, such as the star-nosed mole or the bat, it is much more difficult for us to imagine their Umwelt because their senses and neural structures are so different from ours. Imagine trying to catch a swift moving insect in three dimensions using only hearing. The bat is particularly interesting, so much so that Cambridge philosopher Timothy Sprigge began, through the instrument of Thomas Nagel, an entire approach to the philosophy of mind with the publication of the essay “What is it Like to Be a Bat?” a philosophical Rorschach that lets physicalists, idealists, materialists, empiricists, or whomever see whatever they want.
We humans have been indirectly expanding our Umwelts since before recorded history. The act of extending our reach with a stick, or using lens to magnify our vision, effectively grows the information we can access. Modern advances in science have lead to enormous indirect expansions of the Umwelt. RADAR, for instance, bounces long-wavelength electromagnetic waves off solid objects and the reflections are picked up by an antenna and converted into a spot on a screen or a beep from a speaker to indicate some distant object not directly sensed but now actionable within our Umwelts. Though a spot on a screen is not the same thing as sensing radio waves directly, neither is a sonar microphone substitute for our inability to hunt fly insects using our ears.
Since the World is our Idea and that Idea depends on what information we have direct access to, we may now ask, can we expand our Umwelts directly? The answer is… probably. I will now suggest a realistic method to do so with vision.
In 2009, Katherine Mancuso, working in the laboratory of Jay Neitz at the University of Washington, published a paper in Nature. She reported that she and her team were able to cure an adult squirrel monkey of colorblindness. From birth, this monkey called Dalton was unable to distinguish reds and greens. This is normal in male squirrel monkeys — only the female typically has full trichromatic color vision.
The researchers took a commercially available gene therapy vector, a recombinant adeno associated virus (rAAV) and modified it to carry a clone of human L-opsin cDNA. The virus, which is harmless and designed not to provoke a large immune reaction, inserts the opsin cDNA into the retinal nerve cells. The genetic payload was further endowed with the L/M-opsin enhancer and promoter regions that were appended upstream from the opsin gene itself. These signals drive expression when in a certain type of cell — M-cone cells in this case. The cells see these signals and transcribe and translate them into proteins as if they were their own. The whole construct was purified, concentrated, and injected into Dalton’s retinas.
Based on previous studies targeting GFP to M-cones using the same promoters and adjusting for the greater titers (viral concentration) they used with the L-opsin cDNA rAAVs, the authors estimated that up to 36% of the M-cones would express the L-opsin. At about 20 weeks, testing revealed the treated monkeys were able to perform discriminations similar to the fully trichromatic female monkeys. The authors conclude that, indeed, the animals gained full color vision, or more aptly, the naturally colorblind males were enhanced — granted a new dimension of sensory experience. The authors recognize the tantalizing possibilities, writing: “Future technologies will allow many opportunities for functions to be added or restored in the eye.”
They refrained from speculation beyond that, so let us take up the challenge.
Here we can be bold and use our imaginations. If they can take a naturally colorblind monkey, an animal that normally expresses only two photopigments and give it three — then we should be able to take a normal human with three photopigments and give them four. I propose taking an ultraviolet sensitive photopigment from birds, and using this technique, we should give this ability to humans.
The common pigeon harbors a well-known photopigment sensitive to ultraviolet wavelengths. The SWS1 opsin has a peak sensitivity of 393 nanometers and extending down to about 320nm. This is far enough away from the normal human S-type photopigment (with a peak sensitivity of around 430nm) to provide differing information to the ganglion cells, but not so far into the UV that the lens will filter out too much of the incoming light. The genetic sequence of the gene is known. Its size is comparable to that of the other opsins in humans. There are no technical or theoretical challenges left to overcome in order to place it into a rAAV (recombinant adeno-associated virus) vector just as Mancuso was able to do with the human L-pigment — specifically, we could be simple medical procedure to install this fourth pigment
A treatment of this kind would leave the patient with the ability to perceive four primary colors. According to Dr. Neitz, this would increase the number of total colors we can perceive to about 100 million, we can see about 10 million colors now with our three receptors. There actually exists evidence that some women already have four receptors, though not one in the ultraviolet range. They are thought to have two versions of the red receptor, as the red receptor resides on the X chromosome, of which women have two. Were such women given our treatment, they would be able to perceive five primary colors. But what would this experience of a new color be like?
Just like the colorblind man cannot fathom the third primary color we all take for granted, we cannot now imagine what this new color will look like until we experience it for ourselves. First, imagine the experience of the man with red-green colorblindness (i.e. Daltonism). Men with this condition are unable to resolve red and green. If you show them two apples and tell them to choose the green one, they will not do better than chance. A colorblind person may use a spectrophotometer on the apples and receive a reading of 660nm for one and 520nm for the other, consult a table and call one green and the other red. Without this technology, he would wonder what features of those apples that are invisible to him would allow others to always choose the sweet apple and never accidently bite into the sour one. He sees the world with one fewer primary colors than we do. For him, it is impossible to imagine this third color that we know so well and that mixes so beautifully with its chromatic brothers to give the full spectrum of the rainbow.
So the question is: should we open up the fourth primary color to human beings? Is there something improper about enhancing vision this way? Certainly, a market for this sort of enhancement exists and most of our H+ Magazine readers would readily agree that it is improper for anyone to say what a person can and cannot do with their own bodies. This sort of sensory augmentation can definitely be considered under the umbrella of cognitive enhancement discussed at length by Nick Bostrom and other transhumanists. For ethicists, careful examination shows that this may not even be an interesting problem. Logically, it is no different than other common techniques used to augment sensation. Many similar procedures are common today. Glasses and contact lenses constitute sensory augmentation of the most uncontroversial type. For a medical procedure that is comparable to retinal gene therapy that leads to new dimensions of color vision, one need look no further than laser surgery for visual acuity. This is the most similar comparison, because both are — or would be — expensive and therefore available only to those who can afford it. On the other hand, the materials necessary for the primary color augmentation are much cheaper and easier to manufacture than the complex machines of radial keratotomy or laser-assisted in situ keratomileusis, so arguments about unequal availability should be mitigated.
Modern neuroscience has reached the level where substrate level augmentations are now possible. Gene therapy is seen as a great hope to cure a variety of diseases. It has been worked on with great passion and the genius of thousands of committed scientists, since its beginnings as potential cure for cystic fibrosis. Unfortunately for sufferers of CF, it has proved enormously difficult to treat with gene therapy because it’s a somatic affliction and affects an enormous range of epithelial cells throughout the body. Targeting gene therapy vectors to these far flung cells and variety of cellular species is a technical challenge and one that will be overcome. The eye provides a unique location, a natural corral in which the concentration of gene therapy vectors can be controlled, aided by the small variety of cell types in the retina (they are nearly all nerve cells). In fact, in 2008, researchers from the Scheie Eye Institute at the University of Pennsylvania (among many other places, including Italy, Pittsburgh, Maryland and Oklahoma), published a paper in the New England Journal of Medicine on the safety and efficacy of treating a congenital form of blindness called Leber’s congenital amaurosis (LCA). Sufferers of one form of LCA have a defect in a gene coding for a protein that unfolds used photopigments back to their receptive state. Using a rAAV similar to Mancuso’s and carrying the proper form of the gene, these researchers were able to replace the faulty gene with the correct one. All three patients receiving the retinal injections showed improvements in vision and none had any adverse immune reactions to the virus. Six months after the study the vision gains remained.
All this speaks not only to our ability to successfully undertake the color enhancement procedure, but also to its ultimate safety for future augmentees. The cost/benefit calculation between an enhancement and a therapy can’t be ignored. But imagine the potential benefit to the advancement of gene enhancement therapy that a treatment for human baldness would bring. It would undoubtedly be perceived as a net good.
If, as Schopenhauer said, the World is indeed our Idea, do we not have an obligation to reach as much of it as possible? How, if at all, will our Idea change with the added information of a fourth primary color? Why stop at four? There’s no need to. Our Umwelts depend on what information we can collect from the World. Shouldn’t we try to expand ours? Is a richer experience of the world not a dream of every person? What can an artist do painting with four primary colors instead of three? How many computer monitors can technology companies sell when needing to add an extra pixel color? What might scientists learn using smaller wavelength UV light in their microscopes to see smaller objects with their own eyes? Who knows what we may learn.
Eyeborgian Filmmaker Rob Spence