Imagine you could magically make your body change colour. Would this not be seriously fun? And useful too! Picture this – you’re having a catch up with an office friend over a cup of tea, and then somebody that you both don’t like enters the room. All of a sudden you both change colour to blend in with the office kitchen! Did you cause the colour shift? Well, maybe on some level, because you both wanted to avoid Derek and his renowned two-hour sermons. But that’s by the by for now. The question I want to focus on is, do you suspect that you would even notice that you and your mate just changed colour? Yes, of course you would!
So why is it commonly assumed that octopuses can’t? Octopus people – or the people who study octopuses (teuthologists) – they’re really scratching their tentacles on this one (Dröscher 2016). Why? Because according to what we know about vision through the study of human eyes and neural anatomy, octopuses shouldn’t see colours. Experimental data hasn’t fully concluded either way, and the most confusing point is that our tactile friends are very colourful indeed. They seem to have a knack of blending in with their surroundings, with some sister cephalopods like cuttlefish being especially nifty. It just seems incomprehensible, especially to the scientists working on these fascinating creatures, that the very organisms who are lighting up the ocean are completely unable to perceive their own colourful beauty.
What’s going on?
Do you want my opinion? Ok, thanks for asking. Here it is. I think there are at least two issues at play. Firstly, we don’t know how octopuses are wired up, and what software they are running on their hardware body. Granted, they may contain similar-looking organs to humans, but here’s a strange-but-true fact for you; cephalopods have three hearts, multiple brains and their post-transcriptional RNA editing system makes our own look completely undeveloped (Liscovitch-Brauer et al. 2017). To put it simply, we’ve both got DNA etc, but octopuses use these ingredients in a completely unexpected way that makes no sense to us right now. They really are very alien!
The second point is this – we need to stop talking about light waves and the experience of colour as if they are the same thing. Experience of colour is qualia, and although the experience of colour may be correlated with light entering the eye and being transmuted into electrical data in the brain, we as scientists have absolutely no clue as to how electrical data is turned into a movie in the mind that I then experience as the world of colours, sounds, taste etc. This is an essential point to consider when talking about what octopuses, or any other organisms, see or experience. How can we know, aside from at best an educated guess?
This conundrum crescendos with something that I find remarkable. Some scientists are actually not excluding the possibility that octopuses may be seeing through their skin! Yes, you heard correctly. This is somehow seen as a viable possibility. My fascination lies in the strange position we find ourselves in as scientists trying to navigate this age of anti-anthropomorphism, because try as we may, it seems that we cannot help but expect other organisms to experience the world in a similar way that we do. Octopuses are a great frustration/mystery to many studying them precisely because they have eyes that seem adapted for seeing a world of black and white, and yet they are certainly not afraid of being colourful (at least in our eyes)!
Dröscher, A. 2016. “Pioneering Studies on Cephalopod’s Eye and Vision at the Stazione Zoologica Anton Dohrn (1883-1977).” Frontiers in Physiology 7 (618)
Liscovitch-Brauer, N. et al 2017. “Trade-off between Transcriptome Plasticity and Genome Evolution in Cephalopods.” Cell 169 (2):191–202