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Mind in Motion

Page 7

by Barbara Tversky


  When I was a kid growing up in Far Rockaway, I had a friend named Bernie Walker. We both had “labs” at home, and we would do various “experiments.” One time, we were discussing something—we must have been eleven or twelve at the time—and I said, “But thinking is nothing but talking to yourself inside.”

  “Oh yeah?” Bernie said. “Do you know the crazy shape of the crankshaft in a car?”

  “Yeah, what of it?”

  “Good. Now, tell me: how did you describe it when you were talking to yourself?”

  So I learned from Bernie that thoughts can be visual as well as verbal.

  CHAPTER THREE

  Here and Now and There and Then: The Spaces Around Us

  In which we examine the ways that the space around the body and the space of navigation are represented in the mind and the brain, providing support for the premise of the entire book, that spatial thinking is the foundation for abstract thought.

  THE WORLD AROUND US

  Understanding the space around us seems easy. We only have to look at it. It’s right there in front of our eyes. But our heads keep moving, our eyes keep moving, and so do our bodies. That rich world around us keeps changing as our eyes move, as we move. Even when we can’t see it, we keep track of the world that was once in view and no longer is. What’s there and where it is. You probably know what’s behind you now without looking. Whenever you sit on a chair without looking backward, whenever you go up or down stairs without staring at your feet, whenever you return to the house to fetch the umbrella you left in the closet, you’re relying on a world in the mind, but not in view. If I’m walking in midtown Manhattan and somebody asks me how to get to Carnegie Hall—that really happens!—I resist saying, “Practice,” and tell them how to get there, even though Carnegie Hall is nowhere in sight. The world that is in the mind but not in sight is a skeletal world, not as precise or richly detailed as the one in sight. That sense of where things are in the world around us is carried in the mind in a mental spatial framework, a framework that gets updated as we move and enlarged as our experience is enlarged.

  The mind creates and carries several different kinds of spatial frameworks. Like real-life frameworks, bookshelves and cabinets and networks of trains and roads, the formats of mental spatial frameworks can be used and reused, and what’s arranged on them can be changed and rearranged. Mental spatial frameworks can be used to store and organize ideas, any kind of idea, not just places and landmarks. Corollary of Fifth Law of Cognition, Cognition mirrors perception: Spatial mental frameworks can organize ideas. Any ideas.

  Centered inside one basic type of spatial framework, a three-dimensional one, is you, or a stick figure of you. This is a body-centered framework, one that represents what is around the body relative to the body. Not to the encompassing world. The mind creates a mental spatial framework, an imaginary stick figure extending from the three axes of the body, front-back, head-feet, and left-right, and hangs what’s around the body on extensions of those axes. As the body moves and turns, the mental spatial framework is updated. It goes with you.

  Just because you’re at the center of your spatial framework and keeping track of everything around you relative to your own body doesn’t mean you can’t get out of your spatial framework and into someone else’s, doesn’t mean you can’t take someone else’s perspective. On the contrary, it’s exactly because we’re so good at keeping track of the things around us that we are also good at jumping into someone else’s framework, at taking a different spatial perspective, even when it flies in the face of our own. We just hang different things on the front-back head-feet left-right framework and enter a different world. This is why you can give directions from your office to your home when you’re sitting in neither.

  Spatial frameworks allow taking perspectives that are entirely in the imagination. This is how you create the movie that runs through your mind as you read a novel. Creating a movie in the mind from words is in fact how we found support for the strong statements I just made, and that rightfully have you wondering, What’s the evidence? Evidence meant going into the laboratory.

  We began with two questions whose answers converge. We wanted to understand the model of the world around the body in the mind and we wanted to understand the nature of mental imagery created only with words, that movie that runs through your mind when you read. Up till then, most work on mental imagery had begun with pictures, not words. Most work on mental imagery had focused on visual images of things, animals, objects, and the like, and less on spatial imagery. People blind from birth may have excellent spatial imagery without any visual imagery at all. Studying spatial mental models created by language confronts more challenges than studying mental images created by pictures. Our stories were not nearly as engrossing as those on the best-seller list, but they worked. We wrote narratives placing first “you” and later fictitious others in a variety of environments, in a museum, at the opera, at a construction site, and more. Each narrative put “you” in the center of a bubble, with objects located above, below, in front, in back, to your left, to your right.

  Here’s the beginning of one of our narratives. The critical objects are highlighted here, but they weren’t highlighted in what participants read.

  You are hobnobbing at the opera. You came tonight to meet and chat with interesting members of the upper class. At the moment, you are standing next to the railing of a wide, elegant balcony overlooking the first floor. Directly behind you, at your eye level, is an ornate lamp attached to the balcony wall. The base of the lamp, which is attached to the wall, is gilded in gold. Straight ahead of you, mounted on a nearby wall beyond the balcony, you see a large bronze plaque dedicated to the architect who designed the theatre. A simple likeness of the architect, as well as a few sentences about him, are raised slightly against the bronze background. Sitting on a shelf directly to your right is a beautiful bouquet of flowers…

  After people learned the environments, various versions of the narratives rotated them in place, rolled them on the floor, turned them upside down. This was imaginary, no acrobatics required. Remarkably, people had no problem learning these environments and even more complicated ones, and no trouble imagining themselves moving in them and keeping track of everything around them as they did. After each move, people were asked what was now in each direction from the body. What’s in front? What’s above your head? What’s on your right? The task was easy. People easily kept track of what was around them as they moved in their imaginations; they rarely erred. What interested us was how quickly they retrieved the objects in each direction. The narratives were agnostic with respect to locations, the locations of the objects had been chosen by coin toss, but we suspected that some directions from the body would be faster than others. We also asked people how they did it, but their reports were vague and in many cases contradicted their own data. In any case, as good scientists, we trusted their data to tell us what their minds were doing. And they did.

  Before data, some theory. If spatial thinking were like mathematical thinking, all directions would be equipotential, equally fast. But spatial thinking is not like mathematical thinking, and some directions turn out to be systematically faster than others. Which directions are faster depends on asymmetries of the body, of the world, and of the alignment of the body to the world. The body has three axes, and they differ considerably in both perception and action. Two of the body’s axes, front-back and head-feet, have salient asymmetries, both of perception and of action. Of those, the front-back axis seems more critical as it separates the world that can be readily perceived and easily manipulated from the world that cannot be seen or easily interacted with. Our eyes face forward, so do our ears and our noses. And our arms and legs. Unless we are highly adept magicians, our arms and hands are more facile at doing things in front of us than behind our backs. Walking backward is awkward. Our heads swivel, but not all the way, so turning backward requires the whole body. Thus, both input and output, both perception and act
ion, are asymmetric and oriented forward. After the front-back axis, the head-feet axis. More asymmetries, though not quite as strong. Our heads with much of our perceptual apparatus, eyes, ears, and nose, are at the tops of our bodies. Moving in space is controlled by our feet; most of us don’t spend too much time walking on our hands. Finally, left-right. For the most part, our bodies are symmetric left-right, two arms, two legs, a symmetric torso, a symmetric face. True, most of the world is right-handed and handedness is important no matter which hand is dominant. But heavy lifting requires both arms and hands, and walking, both legs and feet. All things equal, objects in the more salient and distinctive directions should be faster to access.

  But all is not equal. If it were only our bodies, then front-back would be fastest followed by head-feet, with right-left the slowest. But the body is in the world. The world, too, has three axes, but only one is asymmetric, the up-down axis conferred by gravity. Gravity, of course, exerts enormous constraints on our bodies, both our appearance and the appearance of everything in the world, and our actions, pulling us to the earth, making uphill harder than downhill. When we’re upright, rather than lying on the couch or tossing and turning in bed, head-feet, our second most salient axis, is aligned with gravity. And when it is, when we’re upright (remember, this is in imagination), we’re fastest at finding what’s above and below us followed by what’s front and back. Left-right is most confusing, and slowest. But when we’re lying down and rolling around, no axis of the body is aligned with gravity, and we respond fastest to objects in front or back followed by those at head or feet and slowest for objects left or right.

  TAKING OTHER PERSPECTIVES

  Now that this paradigm was working, we worked it hard. We wrote stories that put the objects around inanimate things like refrigerators rather than people; our participants had no trouble taking the perspective of refrigerators. We wrote stories that filled two bubbles with different objects around two separate characters and asked people to take each of their perspectives in semi-alternation. Participants didn’t confuse which objects were around which characters and could keep track of where the objects were as the characters’ orientations changed. We asked people to take the perspective of stick figures in diagrams and Homer Simpson dolls in front of their eyes. Those, too, were easy. The patterns of times differed somewhat for some of the versions but in predictable and predicted ways. The essential finding was that, in imagination, people could take many different perspectives, even that of a refrigerator, even that of a Homer Simpson doll in front of them, with ease.

  Yet, all the searching and finding was in imagination. We next asked what happens when people search real environments that actually surround them. The answer was different, depending on whether the environments were brand new or had been learned. When people first entered a new environment (simulated in a lab room), they needed to look to see what was where in order to answer each question of what’s in front, what’s above, what’s to the left. When they looked, they were fastest to find the objects that were closer to their viewpoint. When the environments were new, people were fastest to report what was directly in front of them, next to report the objects 90 degrees displaced, above their heads, below their feet, to right or left, and slowest to report what was behind them. But people quickly learned the environments and stopped looking; they knew where everything was. Then their answers were faster and fell into the same pattern as that of people who had learned the environments from language: fastest to head-feet because of asymmetry and gravity, next to front-back because of asymmetry, last to right-left.

  This is another example of the Fourth Law of Cognition: The mind can override perception. We don’t always look, even when the answer is right in front of our eyes. Memory overrides perception. It’s sometimes faster to find information in the mind than to find it in the world.

  That bubble surrounding the stick figure framework of objects is transportable. Rather than keeping us locked in our own here-and-now perspective, it enables going then and there. It allows taking any number of other perspectives, imaginary and real, as long as we can hang objects and landmarks on the appropriate appendages. It allows taking the perspective of someone right in front of us, even when that perspective conflicts with our own. Here’s the task that shows that. People were shown a photograph like the one in Figure 3.1 of a young man, let’s call him Patrick, seated a table that has a water bottle on his right and a book on his left. He is looking at the book.

  FIGURE 3.1. “In relation to the bottle, where does he place the book?”

  His left hand, palm pointing downward, hovers just over the book. Participants were asked, “In relation to the bottle, where does he place the book?” We were interested in whether people would say “left,” that is, answer from the Patrick’s point of view, or say “right,” answering from their own point of view. Many theorists and laypeople alike proclaim or assume that our own egocentric perspective is primary and that taking other perspectives is unnatural and effortful. This view is intuitively compelling. After all, we see the world from our own eyes, we experience it from our own bodies, from our own egocentric point of view. Virtual reality is giving us opportunities to see the world from other points of view, somebody else’s ego, but even then, the experience is from a single point of view. Theories, intuitions, and proclamations notwithstanding, more participants took Patrick’s perspective than their own egocentric perspective. More answered “left” than “right,” as if in Patrick’s place instead of their own. Spontaneously reversing right and left is all the more impressive because distinguishing right and left is hard—they are frequently confused. The key seems to be action. When the question didn’t imply action, that is, “In relation to the bottle, where is the book?” many, but fewer, people took Patrick’s perspective. When Patrick disappeared from the scene, the vast majority of participants took their own perspective. A couple of people out of sixty-four participants seemed to take the perspective of the opposing wall, but it’s more likely that they just mixed up left and right.

  Simply watching someone act induces us to take their (spatial) perspective. The research on the mirror system, reviewed in the first chapter, showed that viewing action resonates in the viewer’s body; that is, we are programmed to internalize the actions of other people. But perspective taking is more than that: it’s putting yourself in the place of the actor. Watching action can elicit perspective taking for two key reasons. I might take your perspective in order to understand your actions so that I can perform them myself. We learn so many diverse actions from watching, even imitating, others, from tennis serves to working a ticket machine. I might take your perspective to understand your actions so I can prepare my own. Are you tossing something to me? Then I reach out to catch. Are you throwing something at me? Then I’d better duck.

  FLATTENING THE FRAMEWORK: MAPS

  The body-centered framework, even if transportable, has limits, serious ones that evolution caught onto ages ago. The body-centered framework locates objects and landmarks relative to you, the stick figure in the middle, but not to each other. The body-centered framework is egocentric. To think about space more generally, we need to take the ego out of the space and form an allocentric representation. An egocentric body-centered framework is helpful for keeping track of what’s where as you move about, it’s helpful for taking the perspectives of others, and it’s helpful for imagining other perspectives and other places. But it’s not an efficient way to represent where objects and landmarks are relative to each other. And of course we can do that, as can rats and other creatures, by flattening the framework onto a plane and removing the stick figure. Like a map, flattening the framework to a plane not only swallows the stick figure in the middle but also swallows height, the vertical dimension. That flattened framework in the mind is more like a schematic network of places than the GPS map you have in your phone. But networks qua networks don’t capture distances and directions among places, and the mind captures some of that, wi
th, as shall be seen, some simplifications and distortions.

  One of the more remarkable feats of humankind is the creation of maps in the world, making a miniature representation of a large space, a space too large to be seen from one place, abstracting and shrinking that space, and putting that miniature into the world on a virtual page. Our primary experience of the world is from the bubble that encompasses us, updated as we move, our surroundings relative to us. Yet, millennia ago, people began making egoless maps, broad views of landmarks and paths (the flattened framework) relative to each other, views that brought in far more than could be seen from a single place. Creating a map means integrating many different experiences and flattening them to a plane. Some of those experiences come from the moving bubble, but others may be indirect, from other people’s reports or sketch maps.

 

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