In many ways a dog navigates the same world as we do with shared systems and processes across our senses, but in others their reality is dramatically different with a sense of smell so powerful they can count molecules in the air and see ghosts.
I can’t be the only dog lover who frequently looks at their faithful friend and wonders what they’re thinking. Thinking, of course, is a strong word to apply to a canine that isn’t really capable of reminiscing, fantasizing, or long term planning to say the least. Those puppy dog eyes, however, can certainly make it seem like they are more like us than their mental faculties allow, so much so that it can obscure how much they truly are like humans in many ways. For starters, dogs experience the world much the same way we do. The last common ancestor between our two animal families, technically “orders” in the animal classification system, dates back less than a hundred millions years, a short period considering the earliest life goes back about 4 billion. This means we share very similar underlying structures across vision, hearing, smell, touch, and how those senses are processed in the brain. There are differences, of course, but much of it is the same. Light passes through the lens of a dog’s eye to stimulate rods and cones lining the rear of the surface the same way it does in humans. Further, these signals are transmitted via the optic nerve to the brain where the final image is formed using the exact same chemical reactions, supported by many of the same genes. The only real difference is that humans produce chemicals that discriminate between three different colors of light, dogs merely two, suggesting that their vision is as precise and clear as ours, in some cases more so, only with less total colors. We may get the impression in our minds that our companions see the world a little fuzzier than we do given they lack the language to discriminate between objects, but the underlying picture in their own brains is crystal clear.
Likewise, our sense of smell works the same in principle, but in practice a dog has far more chemical receptors for different odors, some 300 million compared to 6 million, and more genes to make those chemicals, resulting in estimates that their sense of smell is up to a million times better than ours. So much so, a recent study suggested that dogs can tell time based on sampling the number of molecules in the air. The study sought to answer a question common to many dog owners. Like magic, the faithful animal somehow knows almost precisely when the kids are coming home from school, moving from whatever comfortable position they occupied during the day, to patiently or not so patiently waiting at the door or window for their approach. The authors proposed that dogs accomplish this with such precision using something like an hourglass, except the grains of time are the molecules from breakfast or the presence of family members who have left the house hours earlier slowly fading throughout the day. In the dog’s brain, the precise quantity of these molecules still drifting through the air later in the afternoon, is associated with when the children arrive home from school; the faded scent reaches a certain level and they know it is time for their people to return. The result is something hard for humans to imagine. Our sense of smell can be a powerful experience and is known to stimulate memories and other reactions in our bodies, but we are capable of nothing like this or even close. The smell of breakfast for us fades shortly after the dishes are done; the scent of a person leaving the room lingers for perhaps a moment or two. The underlying olfactory system in a dog works the same as ours in principle, but is so far superior in practice their sense of smell can’t really be considered anything so simple. It strikes me as far closer to having a second sense of sight, with all the richness of color, perspective, distance, light, and shadow that vision enjoys, perhaps even more peering into a world that we can never see.
The world the canine navigates, however, is roughly equivalent to our own, except without the benefit of language to label the objects in their environment. Here as well, we will find it very difficult to imagine how a dog discriminates between and remembers the various things they encounter. A canine cannot see a tree and say it’s a tree, but somehow there is a mechanism by which they know there are trees and that trees are a distinct category of object, different from themselves, humans, other animals, and even other plants. This mechanism is very hard to conceive given humans are not even able to remember a time where they didn’t have at least limited language skills to label things, but we do know that such a mechanism exists. Most dogs, for example, will eat grass when they are upset to their stomach, but they don’t start chewing on trees, eating the leaves off of bushes, etc. Somehow, they know that grass is grass and they can easily find it. This ability to differentiate and classify objects extends to animals. They knew other dogs are other dogs, people are people, and a difficult to quantify number of additional animals they encounter. We can clearly see this from their behavior toward each. A dog will kill a rabbit, but rarely if ever a puppy though both are the same size. A dog will be frightened off or attempt to scare off a bear, but is likely not to even acknowledge a deer, even 10-15 of them, once they get used to their presence. Birds, however, generally excite them, or at least they do our two dogs. Dogs, of course, are also aware of particular animals in those groups and whether they are known or not, even in some cases how well they are known. Our dogs do not know my name or my wife’s name, but certainly they know us, and can easily identify us by sight, smell, and hearing.
The coonhound, for example, when the weather is warm enough to have the bedroom window open, will hear us coming around the block returning from an afternoon walk, prop herself up on the sill, clamor up against the screen, and bark until we get there. Given consciousness is a unified phenomenon that synthesizes information into a single experience of the world, one can only imagine what the power of a dog’s sense of smell adds to their mental picture of us. They see us clearly, yes, but they also smell us, perhaps even more clearly. This is impossible to visualize, but perhaps we can think of it as the corona of a comet, where our physical form leaves vapor trails behind, drifting and glowing in the dog’s mind, and allowing them to know not only where we are, but where we were. If this is the case, and something like this must be, a dog’s world must be filled with with something very like ghosts, blending an awareness of the present with a lingering past unlike anything humans conceive, as if everything the dog experienced was a bright light that shines in your eyes for a few moments after, but likely for much longer. Imagine a dog beside their owner on the couch. The owner gets up and goes into the kitchen. The dog can still sense the owner beside them, perhaps like a warmth or some other glow that extends in a path straight through the air directly to the fridge. Upon opening the fridge, an explosion of other scents envelopes the owner, and drifts back to the dog. At that point, the dog has a decision to make. Do they remain on the couch basking in the afterglow of their beloved owner’s presence or do they march up to the fridge and hope that same beloved owner will give them a treat?
Dogs are not good planners, but they do make decisions, for better or worse, and those decisions are based on a multitude of factors, some of which will be very difficult for us to understand, again much the same as ours. Energy level and comfort, however, are key to their little worlds. Our coon hound will only sleep on the bed. Indeed, it is something of a life and death issue for her. If she’s denied a spot, she will circle the bed, crying and then barking, until she gets her way. Then she will dramatically ascend, as if to suggest we are lucky she’s there, and primp herself into a spot. The greyhound is more flexible. Sometimes she’s on the bed, and sometimes she prefers a comfy chair in the corner. We have no idea how she makes this decision on a nightly basis, but it’s clear that she is making an actual decision. She doesn’t circle around the room looking for a place to sleep and then stumble onto either the bed or the chair. She goes straight to one or the other. Sometimes, she will start on the bed and for whatever reason decide the chair is preferable, but again she doesn’t get up, stretch, yawn, and then look for another place. She gets up and goes straight from the bed to the chair. This implies that somehow in her little doggie brain she decides a relocation would be preferable for whatever reason, she envisions where she will relocate to, and then does exactly that. The order of this process is hard to discern. Does she decide the chair is preferable and then move? Or does she decide to move and then choose the chair?
Either way, the dog’s brain must encode a map of their home and surroundings, which would also be surprisingly similar to our own mental maps except without markers written in language. Like us, dogs understand on some level that the world around them isn’t static. They know the difference between doors that open and close, for example, and walls that are fixed; they might not know what these things are or what to call them, but they understand enough of their function and that though these objects may look the same, they work differently. They also know that only humans can help them navigate this space, standing, barking, or scratching before closed doors when they want to get through, something they frequently remind us of if your dogs are anything like mine. These maps are generally quite detailed, covering the house and the surrounding property including their favorite spots and some sense of what happens where. On top of this mental map, we can add something like a schedule, what happens at what point in the day. Dogs have more things to do than simply monitor the comings and goings of their humans. Our greyhound generally gets up at 7.30 in the morning, almost precisely so. Whether on the chair or the bed, her usual move is to come over to my side, stretch beside me, and demand a little attention before mommy gets up to take her out for the first walk. The coon hound is older and hence a little lazier. She will remain on the bed half asleep, but eventually discover that it’s time to go out and will follow a few minutes later. Both will promptly return to the bed for the daily breakfast ritual, when the coon hound, still on the bed, will bark the entire time my wife has a muffin, and the greyhound, now strategically positioned on the floor but with full attention on my wife, will wait, her turn to be more patient. There are similar walking and feeding rituals throughout the day, sometimes initiated by one or the other, frequently involving doors, leashes, and people, but generally both will ultimately follow suit.
A broader sense of time and change beyond the daily routine is difficult to determine. Dogs understand that their environment can change – for example, the walking routine can easily be broken by snow or heavy rain – but what they make of these changes except as obstacles to be overcome and whether they know anything about cyclical occurrences like the seasons is unclear. Our dogs generally do not enter the pool area except in the summer, where the coon hound enjoys lazing in the sun and the greyhound searches for rabbits under the bushes, but I’m not sure whether they change their behavior because they associate the area with warmer weather or because their people are in the new spot. If I had to guess, I’d say the people, but still it wouldn’t surprise me if their memory and awareness is complex enough to understand something about the time of the year. There is some evidence of this in that neither even approach the fence to the pool in the winter, and yet both at various times will go straight there in the summer, waiting to be let in, the same as any other door in the house, but that could still just be the change in the overall routine and, of course, it’s not like we can ask them their opinion on the matter. Our dog’s relationship with their favored companions is also something of a mystery, knowing it exists, but unsure precisely how it works except to say dogs do not act the same towards every member of the family and appear to have at least some measure of complexity in each relationship. Even between dogs, patterns of dominance vary widely. The coon hound is far more aggressive around food, prompting the greyhound to run around the house looking for a safe spot to have her treat, but try to move her or get near her favored spot, and the dominance runs the other way. A low growl is all it takes to back her sister off. This complexity extends to relationships with people, where some are favored and others not so much for whatever reason. Our own two dogs, for example, are never happy when my wife and I leave for more than a few hours, behaving rather differently until we return. When we do ultimately return, whether from an overnight or longer trip, the greyhound does a little dance of joy, but the coon hound tucks back her ears and barks, as if to vent her anger that we left in the first place. Clearly, they are aware of our absence in some way and are happy we are back, but how that actually translates in their brain is impossible to say.
Dogs have great memories, able to recognize people and places more than a decade removed, but this does not mean that they reminiscence or miss things in anything resembling a human fashion. Instead, they live in the present mixed with the lingering ghosts of the past and a small window into the future, effectively seeing one action they may take ahead. This implies a few things hard for us to imagine living in a sea of language where everything is labeled, especially when you consider the dog does not know itself, cannot recognize itself, and is unaware of what it looks like. First, we can imagine there is an immediacy to their experience often lacking in humans. For us, the world generally needs to be stripped away in a moment of pleasure or pain, exhilaration or fear, for us to experience it directly without the filter of words or the constancy of our internal monologue. The dog, however, has no filter, no veil they need to peer through or get past. The world, to them, is presented as it is in a much more raw form. Second, this world looks quite a bit like ours with less color, but we can imagine a door is a door, a rock, a rock, and a tree a tree and, if we could somehow view the output of a dog’s visual nervous system, we would be able to recognize these objects and more. What we cannot imagine, however, is what their sense of smell adds to this experience, neither the ghosts of the past lingering around them nor the extra detail we are completely unable to detect. We recognize and place most objects in the world around us based on sight. Sight is equally important to dogs, but they have an entirely different level of scent that is equal in importance if not more so. Somehow, the dog’s experience of the world fuses these two senses together, the same as ours in the way that we can see a steaming plate of food and recognize it as the source of the fine smell, but what that “looks” like in the dog’s mind is impossible to say, anymore than we can understand how they can discriminate between objects without the benefit of language. Lastly, the dog cannot break out of its consciousness anymore than we can. They are as trapped in their own heads as we are, as all things must be, but at least we have each other.