Mind in Motion Page 4
Thinking more broadly, interactions are important in and of themselves, but they are also opportunities for learning actions and behaviors. Being primed to mimic others’ actions can surely help us to learn. We observe others’ actions to coordinate with our own actions, to plan our own actions, but also to learn new actions. Remember that last time you were in an unfamiliar situation, an airport or government office or museum or foreign country. Even at a crosswalk. You probably watched what others were doing. Watching what others do might be the most efficient way to figure out what you need to do. Small children study their older siblings, imitating even incidental irrelevant actions.
AFTERTHOUGHT: MINDS IN OTHER MINDS, BODIES IN OTHER BODIES
We began this chapter, indeed the book, with us, perhaps naturally, with our bodies swathed in skin, separating us from everything else in the world. Yet from the beginning of life we move and act in space, interacting with our surroundings, with space itself, and with the things we encounter in space. Those actions yield sensations, both from within the body and from outside the body. The actions and sensations of our bodies form our conceptions of our bodies.
The world is never static. We are constantly acting in that world and adapting to it. The parts of our bodies that are most important for our interactions in the world are, not accidentally, the ones most salient in our brains and in our minds. How we interact with the things in the world alters the ways we perceive the world. The bodies of others are undoubtedly the most important things we encounter and interact with throughout our lives. We understand others’ bodies and their actions through our own bodies, beginning with the mirror system: viewing actions of others’ resonates in the areas of our brains that create our own actions. Coordinating our actions with others depends on understanding others’ actions but also on shared understanding of what we are engaged in, on rhythm, on joint attention, on the task at hand, and on what surrounds us in the world. The mirror system mediates and reflects just about every kind of action: of our hands, our legs, our posture, our faces. The mimicking is internal, but it can leak out into actual behavior. We imitate each other’s body movements and facial expressions. Mirroring means that the bodies of others get internalized in our minds and our bodies get internalized in theirs.
That spiritual metaphor that we are each parts of others’ minds and they of ours has become a reality. Fascinating new research has refuted what we all learned in elementary biology, that the DNA in every cell in our bodies is identical. Geneticists have found evidence for patchy microchimerism, that is, colonies of different DNA in different places in our bodies. If we carry different DNA, who are we? The research is just beginning, but it is already known that the DNA of babies can colonize in the mothers who carried them, that DNA from transplanted organs can colonize in other parts of the body, that many of us had a fraternal twin who disappeared in utero and that we may be carrying the twin’s DNA. Others aren’t just in our minds. We really are parts of others and they of us, even within our own skin.
CHAPTER TWO
The Bubble Around the Body: People, Places, and Things
In which we learn how people recognize, categorize, and understand the people, places, and things around us. We note that many everyday categories such as chairs and dogs are bins of common features that differentiate them from the feature bins of even nearby categories, such as carpets and snakes. But not always, and then we need to think harder, about dimensions and the features shared across categories.
We live not only in a world of thoughts, but also in a world of things.
—VLADIMIR NABOKOV
SURROUNDING OUR BODIES ARE THE PEOPLE, PLACES, AND THINGS in reach of eye or hand. These are the immediate influences on our perception, on our behavior, and on our thought. In a fraction of a second, before we can find the words to say it, we know where we are, at home, in the supermarket, at the park. We know what’s around us, chairs and tables or shopping carts and packages of food or trees and swing sets. We know who’s around us, what they are doing, making dinner, shopping, swinging. We know what kind of people they are, we can sense their feelings and their health from their faces and bodies, we can judge their social and economic status from their clothing and behavior, we can make good guesses as to their ages, gender, even political leanings. We people wear so much of our insides on our outsides. We take in our surroundings automatically and instantly. Unless we are blindfolded and our ears are covered, we can’t not pick it up. This isn’t to say that we are always correct, but it is remarkable how often we are.
We didn’t enter the world with this impressive ability. Newborns need to learn to see the very elements of objects, edges and corners, and to connect them to form the shapes that are used to recognize people and things. They need to learn to discern and recognize faces and objects and scenes. Babies learn that wordlessly in the first few months of life, simply by looking. It happens so fast that parents miss it unless they know what to look for. Much of that learning happens while the brain is maturing. People who were born blind and gain sight as adults can’t make heads or tails out of what they see, a surprising and often wrenchingly disappointing outcome. Fortunately, blindness from birth has become far less frequent, and with training and experience, some visual competence can be acquired if sight is restored later in life.
Who, what, and where are so fundamental that the brain has specialized regions for recognizing them, in fact, usually multiple regions for each: faces, bodies, objects, scenes. The retina captures information as it is arrayed in the world, if upside down. The upside-down part is the easy part for the brain. Making sense of what’s on the retina is far harder. That information is essentially an array of raw pixels, devoid of meaning. It has to be segmented into figures and background. That entails finding edges and connecting them. Both figures and ground need to be interpreted, given meaning. That happens by routing information from the retina, and for that matter, from all the senses, to different parts of the brain. The different locations perform different computations on the information from the senses, computations specialized for creating the different meanings relevant to our lives, computations specialized for faces, places, and things of all sorts.
When and why are far harder. They can’t be easily computed from sensory input the ways that color and shape and even faces and objects and scenes can be. Except for a handful of hyperorganized individuals who remember the exact dates and details of many events of their lives, the brain doesn’t put a date stamp on events. And even in those perhaps enviable individuals, memory is constructed, the time stamp is added symbolically, in words and numbers from the conventional Gregorian calendar. No brain area codes that. Why is even more complicated, so many events have so many possible explanations, providing endless work for scientists, political analysts, and advice columnists. And disagreements between couples and countries. Because the mechanisms we use to construct when and especially why are imperfect and biased, so are our judgments and explanations.
THINGS
Of all those crucial entities in the world, and components of knowledge, things are the simplest. Yet, there are so many things, how to make sense of them? One way to make sense of things is to group them into categories, but which categories? First, consider this set of categories from the literary philosopher Jorge Borges:
The following is a taxonomy of the animal kingdom. It has been attributed to an ancient Chinese encyclopedia entitled the Celestial Emporium of Benevolent Knowledge: On those remote pages it is written that animals are divided into (a) those that belong to the Emperor, (b) embalmed ones, (c) those that are trained, (d) suckling pigs, (e) mermaids, (f) fabulous ones, (g) stray dogs, (h) those that are included in this classification, (i) those that tremble as if they were mad, (j) innumerable ones, (k) those drawn with a very fine camel’s hair brush, (l) others, (m) those that have just broken a flower vase, (n) those that resemble flies from a distance.
Poetic categories they are, but useful they are not. Good categor
ies sort most things into separate bins, not partially overlapping ones. Good categories should be easy to identify. Good categories should be informative, they should tell us what they’re good for. Good categories should reduce the enormous numbers of different things to a manageable number. The key to recognizing and categorizing things, objects, is shape: objects have shapes and the visual system is biased toward finding them. It homes in on edges and connects the dots when objects occlude other objects.
Around the first year of life, parents and babies begin to play a naming game, pointing, showing, labeling everything that catches the baby’s attention. Babies and children acquire words at an amazing speed. One estimate is that seventeen-year-olds know eighty thousand words. For convenience, let’s say babies begin learning words around their first birthday (of course they begin much earlier, before they can talk). That would mean five thousand words a year, or fourteen a day, and undoubtedly many more of them earlier in life than later. This pace is much faster than the naming game; kids are picking up words for things without being taught. This astounding pace of acquisition is just for the labels of things. To add to the wonder, we have labels for only a fraction of what we, babies, children, learn and know, people, places, things, emotions, and more.
HIERARCHICAL ORGANIZATION
Basic level
Toddlers learn to call the things around them apples and bananas, cars and buses, shirts and shoes. They don’t begin with labels like Gala apple or fruit, Prius or vehicle, knit shirt or clothing. Even adults prefer those simple labels. Calling ordinary things with more abstract or more specific labels sounds odd in ordinary situations. If I offer you a ride because I’ve brought my Tesla X, I’m showing off. If I tell you I’ve brought my vehicle, I’m being silly. If I ask you to put the animal out instead of the dog, I’m implying the dog is wild and beastly rather than docile and friendly. Languages have those more abstract and more specific labels for good reasons, but for everyday use, the middle level, the level of apple, car, and shirt, is preferred. Interestingly, these labels are typically shorter and more frequent than more general or more specific labels (Zipf’s law again: more frequent words are shorter). The default and neutral way of referring to things, the level first used by children, the level of apple and car, has been called the basic level. The more general level, the level of vehicle, fruit, and animal, has been called the superordinate level, and the more specific level, Tesla, Gala apple, and cocker spaniel, has been called the subordinate level.
The basic level is special for many reasons. Objects at the basic level like apples and tables and hammers and belts generally have the same shapes, so it is easy to identify them. So do their subcategories, Gala and Delicious apples, leather and cloth belts, dining tables and coffee tables. Features other than shape, like color or material or size, distinguish one subordinate category member from another. Unless there’s good reason, there’s no need to make people attend to the fine discriminations and plethora of names that labeling at the subordinate level entails. Jumping up a level, to superordinate categories, we see that different kinds of fruit, furniture, tools, and clothing do not share shapes. On the contrary, they come in a variety of shapes. Bananas have different shapes from apples and watermelons, airplanes from cars and trucks, shirts from pants and belts. A composite shape of a couple of apples or hammers is identifiable, but a composite of fruit or vehicles creates a blob. The basic level is privileged for behavior as well as perception. We behave the same way toward apples and bicycles and sweaters, but we behave differently to melons than to apples, to cars than to bicycles, to hats than to sweaters. What fruit and vehicles and tools share are not specific shape or action but something more general, function or use. Fruit are for eating, vehicles, for transporting, tools, for building or repairing. Those properties aren’t visible like peels and pulp, wheels and doors, handles and heads. As a consequence, learning those more general categories based on common function takes longer. True understanding of superordinate categories like tool and vehicle usually doesn’t come in reliably until the early school years.
Basic-level categories like table and apple and shirt are Goldilocks categories, not too abstract, not too concrete. They’re in the middle, right between more general categories that are organized around function, such as furniture, tool, and fruit, and specific ones organized by a variety of features, such as kitchen table, Phillips head screwdriver, and Jonathan apple. Of course, sometimes those general ways of referring are enough: I need furniture for my apartment or fruit for my salad or tools for my garage; sometimes the more specific terms are necessary: only a Phillips head screwdriver works for that screw, only a dress shirt for the reception, only Pippin apples for the pie. Basic-level labels are multipurpose names.
Basic-level categories are not just easy to identify but also provide a wealth of information. What something looks like. What it’s composed of. How it functions in our lives. How we behave toward it. That’s an apple: it’s fruit, it’s round, red or green, grows on a tree, has a peel, pulp, and seeds, is edible, sweet, hard, and juicy. It doesn’t matter if it’s a Gala apple or a Fuji. That’s a shirt: it’s clothing, it covers the upper body, it has holes for the head and the arms and the torso. Same parts and function irrespective of the color or material or cost. The essential features of basic-level objects are typically evident from their shapes, that is, their parts: the seat, back, and legs of a chair; the sleeves, neck, and body of a sweater; the legs, body, and head of a dog. Those parts of objects are the fundamental features that characterize basic-level objects. The parts are clues both to perception, to recognizing the object, and to function, to what they do or what we do with them, to our interactions with them. Parts form a bridge between perception and action. Chairs have seats and legs and backs. Seats and legs and backs look different from each other and serve us in different ways. The seat of a chair is the right size and height for sitting, the legs support the seat, and the back of the chair supports the back of the person. Chairs afford sitting. The sleeves, neck, and body of a sweater look different from each other and are meant to be used by different parts of our bodies. Same for the dog: its distinctive parts, legs, body, and head, serve it in distinct ways. As do our own.
There are so many more things than names for things. The basic level is about naming things in the world, though referring to things that way undoubtedly helps learning to discriminate them in the world. We can distinguish far more things than we can name or describe. Those names are usually sufficient for ordinary conversation, but it is clear that the eye takes in much more. The eye can tell how ripe the banana is and if the fabric of the sweater is soft or harsh and whether the seat of the chair is the right height and if the table is well constructed. The eye can tell if the screwdriver will fit the screw or the shirt fit the baby. The eye recognizes thousands of properties of countless numbers of objects, properties that have significance but that can’t easily be named, and even if they can, the knowing comes before the names.
PEOPLE
Like objects, people have shapes, and the shapes have parts, including faces and bodies. It is hard to overestimate the importance of faces and bodies in our lives. Who is that? Friend or foe? Old or young? Sick or healthy? Native or foreign? Drunk or sober? Rich or poor? What are they feeling? What are they thinking? What are they doing? What are they going to do? So much of that vital information and more is right there on the surface, on the face or in the body. Insides make their way to outsides. We turn to some of that information now. We need to absorb it quickly because it guides our own behavior. And we do absorb it quickly. Quick appraisal doesn’t guarantee accuracy. Remember the First Law of Cognition: No benefits without costs.
Here the benefit is speed, necessary in the savannah or on a dark street or even on a well-lit one—you must flee danger and greet a friend, but not a stranger, who might interpret your smile as an invitation. Identical twins create this problem; I was once miffed when a friend didn’t greet me only to realize that
it was his twin, who quite understandably had no idea who I was. Speed and accuracy trade off in just about everything we do; the trick, as with all trade-offs, is to find the sweet spot. That depends on the costs of both errors, falsely greeting a twin stranger warmly or failing to greet a friend. Mistaking a coyote for a dog can be costly, but mistaking a dog for a coyote less so.
Who: Faces
Try this. Describe a person you know to someone who was at a party with that person but who isn’t sure whom he or she is. Not easy. Easy only in those rare cases when someone has a distinctive feature, neon hair or unusual glasses. In general, everyone has eyes, noses, mouths, and ears. We have good words for those, but they don’t distinguish one person’s face from another’s. We don’t have good words for the features that do distinguish one face from another, the subtle differences among eyes, noses, mouths, and ears, or the subtle differences in their configurations and expressions. Like their parents, each of my three children has “blue” eyes. Five pairs of eyes, five shades of blue, and I’d never confuse them. Despite the near impossibility of describing individual faces, most of us can recognize thousands of them. That disparity says loudly that face recognition can’t be based in language. We don’t normally bother describing faces to distinguish one from another. Rather, we give each face an arbitrary name, a name that has something to do with the person’s family but nothing to do with the person’s appearance. And that disconnect between the vivid appearance and the disconnected name is part of why so many complain that they never forget a face but can’t remember names.