It’s easy to forget that the world as it appears to a dog is very different from the world as it appears to you and me.
I mean that literally.
Because we all “know” that our dogs experience the world differently than we do (at least in the sense that we’ll all agree with that statement if we’re asked). We just do a poor job of keeping that thought in mind when interacting with our dogs. Even if we leave aside the vast but tough-to-classify cognitive differences between our species, the significant perceptual differences are all too easy to overlook.
Take the sense of smell for example. You know, of course, that a dog’s nose is thousands of times more powerful than your own. But it’s easy to forget about the experiential implications of that difference. In fact, it’s very difficult (if not impossible) to accurately imagine what it feels like to have a nose that’s as powerful as a dog’s. I, for one, don’t think that my best imagining work comes remotely close to replicating the richness, complexity, and vibrancy of the smells which populate a dog’s nostrils on any given moment.
Or, alternatively, consider the sense of vision. We all know that dogs are colorblind and can’t distinguish between reds and—
Hold on a second.
First of all, that’s not true. Moreover, this post isn’t designed to be a wandering philosophical rant about the subjective nature of experience. It’s a quick-strike assault on a common misconception, the oft-repeated but incorrect belief that dogs are “colorblind.”
The published, peer-reviewed, data-supported, scientific truth regarding dogs and color perception can be summarized in three points: (1) dogs do perceive colors, (2) the colors that dogs see are not as vibrant as those seen by humans, and (3) dogs can’t see as many colors as humans (they mainly see yellows, greys, and blues).
Now let’s go deeper.
Jay Neitz, a professor of ophthalmology at the University of Washington, is one of the world’s leading color vision researchers. Throughout the 1980s, he conducted experiments aimed at illuminating the capacity for and nature of color vision in the domestic dog. He documented his findings in his often-cited 1989 paper “Color Vision in the Dog.”
In this report, Dr. Neitz describes color matching experiments that he and his research team performed with greyhounds and toy poodles. Using multi-color light-illuminated panels and food rewards, the researchers trained the animals to identity uniquely illuminated panels (the panels were presented as three alternatives, two of the same color and one of a unique color, the researchers rewarded the dogs for identifying the “odd man out”) using their noses.
The researchers tinkered extensively with the wavelength and frequency of the light being used to color their panels, running thousands of trials of different combinations of color type and intensity. The dogs did their part too, nosing colored panels and collecting food rewards. In the end, the researchers obtained some strikingly consistent results, from which we can make some very confident assessments about the nature of canine color perception.
Specifically, Neitz and his colleagues concluded that, instead of seeing a rainbow as violet, blue, green, yellow, orange, and red, dogs see it as dark blue, light blue, grey, light yellow, dark yellow, and very dark grey. An image comparing the complete human color spectrum with the canine one is available here. As you can see, there’s color on the dog spectrum, but it’s limited and muted.
These results were consistent with what scientists already knew about the biology of the canine visual system, mainly that while the eyes of dogs do contain light-catching cone cells, they don’t contain as many of them as human eyes do. Moreover, dogs only possess two different types of cones, tuned to two different wavelength spectrums, while humans (and some other rainbow-seeing primates) have three different types of cones, from which arise our full range of color vision.
For more reading on Neitz and his color vision research, click here.
– Coach Dan