Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [101]
… It either fits in the mouth or it's too big for the mouth …
Of the innumerable objects we see around us, only a very few are salient to the dog. The array of furniture, books, tchotchkes, and miscellany in your home is reduced to a more simple classificatory scheme. The dog defines the world by the ways that he can act on the world. In this scheme, things are grouped by how they are manipulated (chewed, eaten, moved, sat upon, rolled in). A ball, a pen, a teddy bear, and a shoe are equivalent: all are objects that one can get one's mouth around. Likewise, some things—brushes, towels, other dogs—act on them.
The affordances—the typical use, the functional tone—that we see in objects are superseded by dog affordances. A dog is less threatened by a gun than interested in seeing if it fits in his mouth. The range of gestures you make toward your dog is reduced to those that are fearsome, playful, instructive—and those that are meaningless. To a dog, a man raising his hand to hail a cab says the same thing as a man reaching to high-five or one waving goodbye. Rooms have a parallel life in the dog's world, with areas that quietly collect smells (invisible detritus in the crook of the wall and floor), fertile areas from which objects and odors come (closets, windows), and sitting areas where you or your identifying perfume might be found. Outside, they do not so much notice buildings: too big; not able to be acted on; not meaningful. But the building's corner, as well as lampposts and fireplugs, wears a new identity each encounter, with news of other dog passersby.
For humans it is the form or shape of an item that is usually its most salient feature, leading to our recognition of it. Dogs, by contrast, are generally ambivalent about the shape in which, say, their dog biscuits come (it is we who think they should be bone-shaped). Instead, motion, so readily detected by the retinae of dogs, is an intrinsic part of the identity of objects. A running squirrel and an idle squirrel may as well be different squirrels; a skateboarding child and a child holding a skateboard are different children. Moving things are more interesting than still ones—as befits an animal at one time designed to chase moving prey. (Dogs will stalk motionless squirrels and birds, of course, once they have learned that they often spontaneously become squirrels running and birds on the wing.) Rolling quickly on a skateboard, a child is exciting, worth barking at; stop the skateboard, and the motion, and the dog calms.
Given their definition of objects by motion, smell, and mouthability, the most straightforward items—your own hand—may not be straightforward to your dog. A hand patting his head is experienced differently than one pressing continuously on it. Similarly, a glance, even many stolen glances, is different than a stare. A single stimulus—a hand, an eye—can become two things when experienced at different speeds or intensities. Even for humans, a series of still images shuffled fast enough becomes a continuous image: as though changing identity. To the common snail, wary of the world, a slowly tapping stick is risky to walk over; but if the stick is oscillated four times a second, the snail will move into it. Some dogs will endure a pat on the head but not a hand resting there; for others, the reverse is true.
These ways of defining the world can all be seen by watching a dog interact with the world. Dogs entranced by a blank spot on the sidewalk, those whose ears perk at "nothing," those transfixed by an invisibility in the bushes—you are watching them experience their sensory parallel universe. With age the dog will "see" more objects familiar to us, will realize that more things can be mouthed, licked, rubbed against, or rolled in. They also grow to understand that different-seeming objects—the man at the deli, and the deli man on the street—are one and the same. But whatever we think we see, whatever we think just happened in a moment, we are pretty much assured that dogs see and