Re: how can a dog be trained to respond to color?

This sounds like a really interesting experiment, and you're right, you have to control for the dog's response to the card itself versus the dog's response to the color of the card. You want to show that you have trained the dog to sit when she sees a red card, but you think that just seeing the card will cause her to sit, which won't indicate anything about her knowledge of color. One way you could do this would be to use several cards of different colors. The cards should be identical to each other in all other ways (size, shape, even the way you hold them when you show them to the dog) to make certain that the dog isn't learning some other cue (for example, she sits when you hold up the large card, or the rectangular card, which just happens to be the red card). Then you can train her to sit when you present her with the red card, lie down when you present the blue card and roll over when you present the yellow card. (By the way, if she learns the differences between these cards, it is still possible that she is not seeing color per se; she could be responding to what she sees as different shades of gray.) You could even use a "control" card, which is a different color from the others, and to which she is not supposed to respond in any way.

You will have to be very careful to not give her any other kinds of cues, such as voice cues, hand motions or even something as subtle as a wiggle of the eyebrow. (Do you know the story of Clever Hans? He was a horse who, for a long time, was believed to be incredibly intelligent. He would provide answers to addition, subtraction and multiplication problems by stomping his hoof the correct number of times. After a lot of careful observation, someone figured out that Hans was responding to very subtle - even unintentional - signals from the person asking the questions. If the answer was 8, the person might lift his eyebrow just slightly as Hans tapped his hoof for the 8th time, and Hans would know to stop. The moral is, you have to be extremely careful about how you test an animal, because they can pick up on amazingly small cues!) One way to be absolutely certain you are not giving the dog any cues you don't want to is if _you_ don't know what color card you're holding up. This would mean the cards would have to be colored only on one side, but that wouldn't be too hard. Then you could present the card, watch what the dog does, look at the card yourself, and reward the dog if she did the right thing.

I guess I answered a lot more than the simple question you asked, but that should give you some help in designing your experiment to test whether the dog responds to color. I hope you have fun with it, and I hope your dog learns quickly!