Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [69]
One winter we took a trip north, to a place of assertive winter and genuine cold, and were treated to a large snowstorm. We pulled out sleds, found a great big hill, and proceeded to plow an erratic track down it. Pump was suddenly overcome, and ferociously pursued us on each ride downhill, biting, grabbing, and growling at our faces. When it was my fast-moving, snow-covered face being attacked, I couldn't stop her for all my laughing. She was playing, but it was a play I have not seen before: tinged with real aggression. When I managed to rise and shake off the covering of snow I'd gathered on the way down, she calmed at once.
Does this clairvoyance mean that dogs can't be fooled? No. They are astute watchers, but they are not mind readers, nor are they immune from being misled. I was changed for Pump when I leapt on that sled: I was horizontal; I was enrobed in snow gear and snow; and most critically, I was moving entirely differently. I was suddenly a smoothly moving, high-speed prey animal, not an upright, ambling companion.
My dog may have a particular interest in sledders, but her behavior is similar to many other dogs' chasing behaviors. Dogs often chase bicyclists, skateboarders, RollerBladers, cars, or runners. The general-purpose answer given for why they do this is usually that they have an instinct to chase prey. This answer is not entirely wrong, but it is mightily incomplete. It is not quite that dogs think of these objects or persons as "prey," per se. Your motion reveals another dimension to you: you roll! quickly! It is an attribute that alters you in the dog's eyes, which are especially responsive to a certain kind of motion. Mounting and riding a bicycle, you have not turned to prey—as indicated by the fact that your dog greets you, not eats you, on dismount. Their responsive sensitivity probably evolved as a prey-detection tactic, but it will be applied variously. It lends to the dog's experience an additional way to interpret objects and animals in the environment. That way is by the quality of their motion.
There are shared components of sledding, bicycling, or running: a person is moving in a certain way—smoothly and quickly. Walkers are moving, but not quickly: they are not chased. Pump did not recognize me sledding because ordinarily, much as I would like to think otherwise, I am not particularly smooth nor quick in my motions. There is an excess of vertical movement in my walk; I weave to and fro; I gesture a lot—all frivolous in making forward progress.
To stop a dog pursuing a bicycle with a predatory glint in his eye, one can simply interrupt the illusion: stop the bike. The chasing impulse triggered by the visual cells that detected the motion will itself let up. (The hormones involved in the arousal of barking and chasing such a smooth and quick mover may still be coursing through his system, though, for a few minutes.)
Science has confirmed the importance of behavior in identity. Our identities, who we are, are defined partly by our actions, so we can examine how actions inform recognition of personal identity. In one experiment, dogs showed that they have no difficulty distinguishing friendly and unfriendly strangers: those demonstrating different identities. To do this, the experimenters divided participants into two groups and asked members of each group to behave in a prescribed manner. Friendly behavior included walking at a normal speed, talking to the dog in a cheerful voice, and gently petting the dog. Unfriendly behavior included actions that could be interpreted as threatening: an