Louis Zeheralis, age 12, of Gary, Indiana, for his question:
How do they know that dogs can't see colors?
Some time ago, Andy reported that color TV is wasted on the family dog. Lots of dog owners were sorry to learn this and several were miffed enough to challenge the fact. Wanting to share the good things of life with our pets is normal and natural, but this particular concern happens to be wasted sympathy.
Andy`s dog Hoganberry watches TV and may enjoy favorite programs, though he never discusses them. He may identify actors and their activities, especially those famished dogs and their commercial dinners. Or he may merely be interested in the flickering patterns on the screen. Andy's cat Rama watches TV, but the plots fail to influence his lordly character. His cat Pooka loves Gunsmoke, but it turns out that she is just waiting for somebody to holler, "Miss Kitty!" In any case, reliable researchers assure us that dogs see both color and black and white films in shades of gray.
These experts are psychologists trained to make precise tests in animal behavior. Data from another angle is gathered: by biologists who specialize in the structure of eye cells and the optics of vision. The work of both teams supports the conclusion that dogs cannot see colors as we do. You learn a lot about animal behavior as you train your dog to become a polite member of the family, and you know enough to test some of this research.
Your subject for the tests is a sensible, trainable fellow with that two sided quality of intelligence and affection. Most of his reactions spring from his natural doggie impulses. So choose a strong built in impulse such as eating, and treat your dog as a partner in the tests. His hungry tummy never fails to react to a dish of food as his regular dinner time. Assemble 16 dishes in unmatched foursomes of rounds and squares, ovals and oblongs in sets of red, and green, blue and yellow.
Set out a row of four differently shaped blue dishes and serve the dog's dinner in the round one. After a moment of mild surprise he will sniff out the right dish. After a few repeats he can pick the right one without using his sniffer, even when you switch its position. Vary the tests until your evidence proves that the dog can distinguish between dishes of different shapes. Then test him for colors.
Use four round dishes of different colors. He will use his nose to make his selection the first time and every other time also. Experiment with a variety of switches in shapes and colors and note the combinations that he repeatedly checks with his sniffer. Finally you will conclude that he can detect shapes but not colors. Biology researchers in the cells and nerves used in vision reach the same conclusion from another angle: A dog views the world in fine gradings and shadings of the gray range from black to white.
Our tests were much simpler than the complicated experiments done by a trained scientists. He must prove his conclusion beyond a shadow of doubt. His work is checked and redone by fellow scientists and if they fail to verify it, he hangs his head in shame. Tedious tests of vision are highly complex and the job of testing the whole animal kingdom has barely begun. We are sure dogs are color blind but a zillion other questions on animal vision await scientists of the future.