The Colour of Magic – Can we see new colours?

Researchers have revived an idea and a question that has been asked before, probably many times.

Can we see new colours?

For example Terry Pratchett’s first DiscWorld introduced an eighth rainbow colour octarine, a ‘fluorescent greenish-yellow-purple’.

It seems the answer is yes!

The question is not whether our eyes might somehow respond to ultra-violet, like a bee’s, or have more types of colour receptor, like some fishes do.

It’s concerned with a vivid subjective experience of a ‘new’ colour, what I think philosophers would call qualia.

Qualia are hard to explain just from the physical facts. Knowing the wavelength of light may show that it is red but does not explain its redness, the experience we have. Robots can recognise red but that does not seem the same as us seeing its red quality.

The new colours that people can be induced to experience are reddish-green and bluish-yellow.  Scientific American for January 2010 reported these experiments, which improve on ones done many years ago but not fully appreciated at the time.

At Indigo Thoughts you can see images that may let you see bluish-yellow and reddish-green. They work for me to an extent, although it’s hard to keep my eyes crossed, and as soon as I focus on the images the ‘new’ colour goes away.


About partialinsight

One evening I had a stroke. Half my sight vanished overnight. Adapting made me grasp how amazing the visual system and brain are. It also taught me to understand disability completely differently and I'm grateful for the lesson.
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5 Responses to The Colour of Magic – Can we see new colours?

  1. Lynne says:

    Interesting! A couple of comments:
    1. In practice: The Indigo Thoughts images don’t work for me at all. As they say, the process seems to be similar to magic eye pictures, & I’ve never been able to see these. (One eye is so weak that the brain simply ignores its garbled messages, so effectively I have monocular vision.)
    2. In theory: This idea seems to make a lot of sense. People with colour blindness perceive fewer colours than ‘normal’, so I can imagine a different kind of vision that perceives more. Your term ‘redness’ reminds me of how I explain the musical concept of timbre to my students, as, for example, ‘the violin-ness of a violin’.

    • I’ve always had a huge problem with magic eye pictures, with everyone else saying ‘but you must be able to see it’ and me saying irritably ‘well I can’t!’ I can manage to see these ‘new’ colours but only fleetingly. If I lose concentration they are gone.

      I agree about the timbre of instruments and I think the notion of qualia applies to other senses as well: smelling a rose for example, or touching something cold.

  2. Robert says:

    I have fun with colour vision as I’m red/green deficient.

    My understanding is the eye has three sensitivities to colour falling roughly into red green blue and these vary person to person in closeness to each other and level of sensitivity. So red/green problems can be either caused by closeness of the sensitivities or by “amplitude” issues.

    It’s difficult for me to know if my red/green problem is a problem in the red or the green or both or neither 🙂

    Either way we had curtains at home once rhat were to me all colours of the rainbow but to others all greens.

    My gain, others’ loss 🙂

    • Ah that’s very interesting. So colour blindness is not just seeing fewer colours than others, in some circumstances it can mean seeing more! I didn’t know that.

      • Robert says:

        More, I suspect, like AM radio…filter out the carrier wave to be left with some sort of message – perhaps not seeing green in the curtains left me perceiving what I could see elsewhere in the world.

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