Well it’s a pleasure to continue this discussion about color, and a bit of a superb organization allows me to naturally flow from what I think was said before. Now I feel that some of the effects that I wish to talk about may appear somewhat more subtle, perhaps less dramatic, than the wonderful things we’ve seen up until now. And I do want to talk about the ways in which our experience might affect the way we see similarities in color. But in order to do that, perhaps I’d like to try to put some sort of perspective on a memory structure that will allow these operations to take place. I’m going to start with what’s up on the top, which is called a “pictorial register,” which is our sort of internal moving theatre that we all have now. Partly because I had imagined that the more early level stages of vision have been talked about already, and I’m sure if they’re not now, they will be later on, and those affects which, those aspects of our mental processing that come in and construct from the input moving, colored shapes which we’ll call the Pictorial Register, and I’ve a slide to illustrate the world coming in and onto the pictorial register. Where the pictorial register is in the brain is in a way, and by the way I’m not sure if we’ve ever been certain we knew that, somewhere perhaps in the temporal lobes, or earlier in the system in the visual cortex. There exists there known cells that have properties that are more specific to certain aspects of the world—color, motion, etc. can— that have dramatic effects on what we see at our internal pictorial register, and we’ve had some wonderful illustrations of how dramatic those changes can be. If you input something different, as you do if you have an after image, then you’ll see something different. And those effects can be truly dramatic. And what I want to try and say is that there might be other ways in which we might get back to our pictorial register from our memory and have effects which are also, perhaps interesting to comment on.
Now, when we take things from the world, we have to store them somewhere in memory, and it’s a decision, not perhaps right to put it that way, but nevertheless, decisions are made about what we store, and the first thing we like to do is store things in terms of shapes because shapes have relations to meaning and objects. On the left of this diagram, we have an illustration of how we might take from the world shapes in order to store memories of the objects of the world, table, piano, etc. that surround us. Now it is controversial about how this is done, and second there is no scientific agreement about how these representations conform or how they look it up. But I’m going to just pass that by. But that’s the most important thing that we do. Now the very object descriptions are linked up to all our experience of the world, of which I’ve called object knowledge, and for these purposes, one of the things about object knowledge, is that certain objects are colored, and here’s an illustration of something that is wrong, as we saw also in the talk earlier. And there may be very important aspects of that that can feed back into our perception and understanding of the world. Now, that’s nothing about color. Now, because these colors are colors of objects, we know quite a few things about horses, well some of us only know a few things about horses, but one of the things that I know about horses is that they’re generally not blue. That’s something we know about the colors of objects. It’s nothing about color per se. And so it’s a very big decision whether we decide to use our memory store in order to take things from the pictorial register and make a memory bank of shapes or a memory bank of color. Now, a memory bank of shapes or colors is not in the world, they are things we’ve constructed from the world. So the dramatic, if you like, conclusion from this is that there are no natural shapes in our storage of our memory, if we have ideas about triangles, squares, circles, these are things that we’ve constructed. Similarly, and more importantly now, for colors, the claim then is that the color in space is also constructed from the input we have into our pictorial register. And a lot of people in a lot of places in the world don’t bother to do very much about constructing a similarity space in color for them to use. Why should they bother to do it? And the fact that people don’t bother to do it can be seen very clearly from the limited color terms in the many languages of the world. And as the people of the Polynesian islands said to anthropologist when they asked questions about this last century, well, we don’t talk much about colors here, we don’t have any need to. I mean, I need to know that that fruit is the right color to eat, and I can see that color like you can see it, but we don’t need to talk about similarity between colors. And I’d just like to show you how that sort of color space is a possibility that we have constructed. I won’t bother not to talk about how it will link up to names and such, but it will do.
This is a group of people in Namibia who were asked to do some color matching and similarity judgments for us. It’s a remote part of the world, but not quite so remote that somebody hasn’t got the t-shirt, but it’s pretty remote. That’s the sort of environment they live in, and these are the youngsters that I’m going to show you some particular data on. They are completely monolingual in their own language, which has a tremendous richness in certain types of terms, in cattle terms (I can’t talk about that now), but has a dramatic lack in color terms. They’ve only got five color terms. So all of the particular colors of the world, and this is an illustration which can go from white to black at the top, red to yellow, green, blue, purple, back to red again, if this was shown in terms of the whole colors of the spectrum, but they only have five terms. So they see the world as, perhaps differently than us, perhaps slightly plainer. So we looked at these young children, and we showed them a navy blue color at the top and we asked them to point to the same color again from another group of colors. And those colors included the correct color, but of course sometimes the children made mistakes. What I want to show was that the English children and the Himba children, these people are the Himba of Northwest Namibia, start out from the same place, they have this undefined color space in which, at the beginning of the testing, T1, they make errors in choosing the navy blue, sometimes they’ll choose the blue, sometimes they’ll choose the black, sometimes they’ll choose the purple. Now the purple one, actually if you did a spectral analysis, the blue and the purple, the one on the right, are the closest. And as you can see, as the children got older, the most common error, both for English children and the Himba children, is the increase (that’s going up on the graph) of the purple mistakes. But, their language, the Himba language, has the same word for blue as for black. We, of course, have the same word for the navy blue as the blue on the left, only as the children get older, three or four, the English children only ever confuse the navy blue to the blue on the left, whereas the Himba children confuse the navy blue with the black. So, what’s happening? Someone asked yesterday whether the Sapir-Worf Hypothesis had any currency. Well, if it has a little bit of currency, it has it certainly here, in that what is happening, because the names of colors mean different things in the different cultures, because blue and black are the same in the Himba language, the actual similarity does seem to have been altered in the pictorial register. So, the blues that we call blue, and the claim is that there is no natural category called blue, they were just sensations we want to group together, those natural categories don’t exist. But because we have constructed these categories, blues look more similar to us in the pictorial register, whereas to these people in Northwest Namibia, the blues and the blacks look more similar. So, in brief, I’d like to further add more evidence or more claim that we are constructing the world of colors and in some way at least our memory structures do alter, to a modest extent at least, what we’re seeing.