Colour Blindness
As many as twenty-five million North Americans may be walking around with a congenital, incurable, and occasionally life threatening condition. I’m talking about colour blindness. This problem may affect one in twelve men and one in two hundred women, and often we are unaware of it. I only realized I had a slight touch of it when my wife pointed out that my green socks were actually blue!
John Dalton, the famous chemist who developed atomic theory, was afflicted with the most common and dangerous form of colour blindness. He was unable to distinguish red from green.
Sufferers with this condition can only tell that the traffic light is red by the position of the light. When a red light has no such additional information to clarify its colour, colour blindness can be quite dangerous.
The retina at the back of the eye contains receptors called “cones,” which can distinguish different colours. In colour blind people, different colours produce the same signals from the cones. This information is then transmitted through nerve cells to the brain as similar colours.
There is the possibility that in the future, opticians may be able to offer colour blind people eye glasses with special sensors. These will be able to transform any light falling on them into colours, which the wearer’s retina can distinguish.
So next time you choose that special tie, check with a friend to make sure it matches.
As a child I was intrigued with the concept of colour. I would wonder if bulls really saw red capes, or if animals and birds saw in colour at all. I wondered if the blue colour I see is the same as what you call blue. Was the colour in the object or in the eye of the beholder?
Perception is an intriguing concept to consider. In part, it is enabled or limited by our physical structure. Those without retinal cones can’t see colour. The old black and white television operated without cone equivalents. The viewer could only adjust the brightness, not the colour. The tv couldn’t handle colour because it wasn’t wired for it. But part of our perception rests in what we select to pay attention to in our environment. We hear our child’s call in the night, but not the truck driving down the street outside our window. We see our street coming up at the next corner, but not the car stopping in front of us. We focus our attention on certain clues but not others. Furthermore, part of what we perceive is filtered through our past experience. We understand actions on the basis of our personal history. So was that stranger gazing at us or just staring off into space?
One aspect of parenting is to teach children how to interpret what they see. One purpose in education is to teach students what to look for. Perception and attribution go hand in hand. They are results of our experiencing a sensation, but distinct from it.
Perception is key when we consider spiritual questions. What one person ‘sees’ in the evidence is often not the same as the next person. Some don’t even see the evidence. Others might see it, but don’t acknowledge it. They don’t pay attention to it. It is peripheral, unimportant. Such information doesn’t get through their attention filter.
Still others see the evidence but attribute it to other causes - usually naturalistic ones. Perhaps indeed the evidence can be explained at one level by natural causes, but that doesn’t necessarily mean that that is all there is to say on the matter. Other attributions can be complementary without being contradictory.
Though perception and attribution are important, they are not the whole story. For something to be meaningful, it needs to be personalized. There needs to be some emotional tone infused into the mix before we will commit to something in our heart and engrave it on our memory.
David Humphreys and Debbie Hughes
© August 2004
