Saturday, March 24, 2007
Johns Hopkins scientists have improved the colour vision of mice. How did they know they had done it? With the aid, it seems, of ingenious tests that rewarded mice for showing higher than average colour discernment. The mice became trichromatic - possessing three colour receptor cells - like us, rather than dichromatic like most mammals. But there are also tetrachromats, creatures which possess four colour receptors. There are thought to be some human tetrachromats, always women for genetic reasons. But it is hard to be sure; even though we might detect four receptors, we would have to rely on subjective reporting to establish that they really were seeing colours differently. Visualising what these people would see is impossible, like visualising four spatial dimensions. No picture of what they see is possible since the rest of us would only see it trichromatically. Promising human subjects have been researched. One of their symptoms is their insistence that they are wearing matching clothes when everybody else think they clash. This gives me vertigo. I know our exact inner experiences are inaccessible to each other, but this seems an alienation too far. Tetrachromats, for me at least, would imply a world and even a rationality that is not our own. I'm no longer even sure if that car I was driving yesterday really was blue.
Posted by Bryan Appleyard at 7:22 am