Colour and Vision: Some Thoughts

On Saturday, after much squeeing from me, my partner and I went to the Colour and Vision exhibition at the Natural History Museum. I had wanted to go for a while, mostly because I'm a sucker for colour and shiny. It was all that I expected - and a little more besides.

As you'd expect for an exhibition which is all about seeing colour, it's visually very attractive - which is why I came in the first place! The first thing you see as you walk in is an installation - Our Spectral Vision - by artist Liz West, who primarily works with colour. Despite basically being a room filled with prisms which change colour with angle, it's surprisingly serene and contrasts sharply with the hustle and bustle of the Natural History Museum on a Saturday during school holidays. As you walk through, be sure to look at the floor - it asks questions about colour and how we perceive it. Some of them stick.
Our Spectral Vision by artist Liz West - many-hued prisms
Our Spectral Vision (Liz West)
The first part of the exhibit is all but monochromatic, which might seem strange in an exhibition all about colour, but reflects the origins of eyes: photoreceptors which could tell light from dark...and that's about it. This part of the exhibit is also really fascinating for showing the origins of the eye and refuting the canard that the eye is irreducibly complex. It also gets points from me for showing Hallucigenia, my absolute favourite from the Cambrian explosion. (Seriously. I love physics, but I suck hard at biology. I'm so glad I went to this exhibit and learned a little more; the Natural History Museum is very good at pitching its exhibits to all ages.) They even have Darwin's preserved pet octopus!

If you dislike dissected body parts or have a fear of eyes looking straight towards you, you might do best to duck past the huge wall of eyes as you enter the second part of the exhibit.

preserved eye in jar
Yes, there is a huge wall of eyes. Yes, you read that correctly. Some are photographs, some are preserved and dissected. I can quite happily gaze at dissected body parts and skeletons all day. If you could too, the Grant Museum of Zoology is an entire free collection dedicated to that. I had great fun looking at the eyes and even tried to see if the tapetum lucidum in a cat's eye still worked, with mixed results.

Thankfully, you can duck past the wall of eyes and look at the six major phyla which do have some kind of eye. Some specimens are stuffed; some are preserved in alcohol. It's very interesting to think about how they all see differently; thinking about how a vertebrate would see is comparatively easy, but some other species (like the cock-eyed squid) have stranger setups, because they live in different environments. Some species even have eyes but no brain - they see, but they don't process the images and the information instead goes directly to the muscles.

abalone shell

iridescent shell
The next part of the exhibition is dedicated to colour and its uses, and is visually stunning. As you enter, a peacock sits on top of the first cabinet and introduces you to structural colour, a phenomenon where the colour is in fact built in to the material. This is responsible for phenomena like iridescence, and there's plenty on show here. This is contrasted with colour derived from pigments, which is more uniform and fades over time. (There are also surprisingly few types of pigment in the natural world.)
common blue

Colour is also used as camouflage, to mark danger, or to copy the coloration of dangerous organisms. There are plenty of exhibits to illustrate this and part of me thinks that this was an excuse to bring out some of the museum's collection! Though visitors complain about some of the exhibits being old and faded - and having the stuffed animals in the sunniest part of the museum is not the greatest idea - there are many more in the archives which simply aren't put on display, or which are only brought out for special events like the late-night openings.

Sometimes colour is a by-product of a wanted property; for example, nacre is iridescent and striking, but also strong. Humans value nacre for its beauty, but other organisms (like abalones) have shells with an inner layer of nacre because of their strength.

Sometimes we don't know why certain organisms have colour, and that's okay. Evolution proceeds by subtly different iterations, most of which are not hugely useful. This is why some mechanisms are surprisingly inelegant or even stupid. On the other hand, we're only just learning to do some things which evolved billions of years ago...

...The final part of the exhibit is the one which made me think the most, and it's about how we think about colour. In a short video, artist Neil Harbisson, who cannot see colour, talks about his experiences. In our society we are inclined to medicalise people who do not fit a certain specific image and to treat them with pity, as if they lack something. (Don't get me wrong. Disability can be horrible to live with. But condescension does not help.) Harbisson actually talks about how the way humans use colour can cause problems, but also how people who have a usual colour range will never experience things like a greyscale sunset. It makes me think about how small our worldview really is, how we grow up with one specific perception and can rarely look outside it. We can see from about 400-700 nanometres. That's the visible spectrum. Every colour we can see lives inside a 300-nanometre box. I would love to be able to see from the longest radio waves to the shortest gamma ray. This part of the exhibit also touches a little on synaesthesia, a phenomenon which about 4% of the UK population experience; essentially, sensations are "mixed up" in the head, so someone might be able to see letters or taste sounds. Harbisson had an antenna implanted into his head which allows him to hear colour as different frequencies. This sounds amazing and has definitely affected his perception, and I was left wondering how it feels to hear a world as visually noisy as ours. He actually exhibited his work on this, which I would love to see. Though synaesthesia is comparatively rare, I would pay to see an exhibit on how synaesthetes see the world and to challenge what is normal.

I learned a lot and have a lot to think about - and feasted on the shiny too. Not bad for a day out!