Everything Is Obvious

by Duncan J. Watts

  What people appreciated less, however, is that following the instructions of authority figures is, as a general rule, indispensible to the proper functioning of society. Imagine if students argued with their teachers, workers challenged their bosses, and drivers ignored traffic cops anytime they asked them to do something they didn’t like. The world would descend into chaos in about five minutes. Clearly there are moments when it’s appropriate to resist authority, and most people would agree that the situation Milgram created in the lab would qualify as such a moment. But what the experiment also illustrated was that the social order that we take for granted in everyday life is maintained in part by hidden rules that we don’t even realize exist until we try to break them.

  Based on this experience, and having subsequently moved to New York, Milgram had begun to wonder if there was a similar “rule” about asking people for seats on the subway. Like the rule about obeying authority figures, this rule is never really articulated, nor would a typical rider be likely to mention it if asked to describe the rules of subway riding. And yet it exists, as Milgram’s students quickly discovered when they went about their little field experiment. Although more than half of the riders asked eventually surrendered their seats, many of them reacted angrily or demanded some explanation for the request. Everyone reacted with surprise, even amazement, and onlookers often made disparaging remarks. But more interesting than the response of the riders was that of the experimenters themselves, who found it extremely difficult to perform the experiment in the first place. Their reluctance was so great, in fact, that they had to go out in pairs, with one of them acting as moral support for the other. When the students reported their discomfort to Milgram, he scoffed at them. But when he tried to do the experiment himself, the simple act of walking up to a complete stranger and asking for his or her seat left him feeling physically nauseated. As trivial as it seemed, in other words, this rule was no more easily violated than the obedience-to-authority “rule” that Milgram had exposed years earlier.2

  As it turns out, a big city like New York is full of these sorts of rules. On a crowded train, for example, it’s no big deal if you’re squeezed in against other people. But if someone stands right next to you when the train is empty, it’s actually kind of repellant. Whether it’s acknowledged or not, there’s clearly some rule that encourages us to spread out as much as we can in the available space, and violations of the rule can generate extreme discomfort. In the same way, imagine how uncomfortable you’d feel if someone got on your elevator and stood facing you instead of turning around to face the door. People face each other all the time in enclosed spaces, including on subway trains, and nobody thinks twice about it. But on an elevator it would feel completely weird, just as if the other person had violated some rule—even though it might not have occurred to you until that moment that any such rule existed. Or how about all the rules we follow for passing one another on the sidewalk, holding open doors, getting in line at the deli, acknowledging someone else’s right to a cab, making just the right amount of eye contact with drivers as you cross the street at a busy intersection, and generally being considerate of our fellow human beings while still asserting our own right to take up a certain amount of space and time?

  No matter where we live, our lives are guided and shaped by unwritten rules—so many of them, in fact, that we couldn’t write them all down if we tried. Nevertheless, we expect reasonable people to know them all. Complicating matters, we also expect reasonable people to know which of the many rules that have been written down are OK to ignore. When I graduated from high school, for example, I joined the Navy and spent the next four years completing my officer training at the Australian Defence Force Academy. The academy back then was an intense place, replete with barking drill instructors, predawn push-ups, running around in the pouring rain with rifles, and of course lots and lots of rules. At first this new life seemed bizarrely complicated and confusing. However, we quickly learned that although some of the rules were important, to be ignored at your peril, many were enforced with something like a wink and a nod. Not that the punishments couldn’t be severe. You could easily get sentenced to seven days of marching around a parade ground for some minor infraction like being late to a meeting or having a wrinkled bedcover. But what you were supposed to understand (although of course you weren’t supposed to admit that you understood it) was that life at the academy was more like a game than real life. Sometimes you won, and sometimes you lost, and that was when you ended up on the drill square; but whatever happened, you weren’t supposed to take it personally. And sure enough, after about six months of acclimation, situations that would have terrified us on our arrival seemed entirely natural—it was now the rest of the world that seemed odd.

  We’ve all had experiences like this. Maybe not quite as extreme as a military academy—which, twenty years later, sometimes strikes me as having happened in another life. But whether it’s learning to fit in at a new school, or learning the ropes in a new job, or learning to live in a foreign country, we’ve all had to learn to negotiate new environments that at first seem strange and intimidating and filled with rules that we don’t understand but eventually become familiar. Very often the formal rules—the ones that are written down—are less important than the informal rules, which just like the rule about subway seats may not even be articulated until we break them. Conversely, rules that we do know about may not be enforced, or may be enforced only sometimes depending on some other rule that we don’t know about. When you think about how complex these games of life can be, it seems kind of amazing that we’re capable of playing them at all. Yet in the way that young children learn a new language seemingly by osmosis, we learn to navigate even the most novel social environments more or less without even knowing that we’re doing it.

  COMMON SENSE

  The miraculous piece of human intelligence that enables us to solve these problems is what we call common sense. Common sense is so ordinary that we tend to notice it only when it’s missing, but it is absolutely essential to functioning in everyday life. Common sense is how we know what to wear when we go to work in the morning, how to behave on the street or the subway, and how to maintain harmonious relationships with our friends and coworkers. It tells us when to obey the rules, when to quietly ignore them, and when to stand up and challenge the rules themselves. It is the essence of social intelligence, and is also deeply embedded in our legal system, in political philosophy, and in professional training.

  For something we refer to so often, however, common sense is surprisingly hard to pin down.3 Roughly speaking, it is the loosely organized set of facts, observations, experiences, insights, and pieces of received wisdom that each of us accumulates over a lifetime, in the course of encountering, dealing with, and learning from, everyday situations. Beyond that, however, it tends to resist easy classification. Some commonsense knowledge is very general in nature—what the American anthropologist Clifford Geertz called an “ancient tangle of received practices, accepted beliefs, habitual judgments, and untaught emotions.”4 But common sense can also refer to more specialized knowledge, as with the everyday working knowledge of a professional, such as a doctor, a lawyer, or an engineer, that develops over years of training and experience. In his address to the annual meeting of the American Sociological Society in Chicago in 1946, Carl Taylor, then president of the association, put it as well as anyone:

  By common sense I mean the knowledge possessed by those who live in the midst and are a part of the social situations and processes which sociologists seek to understand. The term thus used may be synonymous with folk knowledge, or it may be the knowledge possessed by engineers, by the practical politicians, by those who gather and publish news, or by others who handle or work with and must interpret and predict the behavior or persons and groups.5

  Taylor’s definition highlights two defining features of common sense that seem to differentiate it from other kinds of human knowledge, like science or mathematics. The
first of these features is that unlike formal systems of knowledge, which are fundamentally theoretical, common sense is overwhelmingly practical, meaning that it is more concerned with providing answers to questions than in worrying about how it came by the answers. From the perspective of common sense, it is good enough to know that something is true, or that it is the way of things. One does not need to know why in order to benefit from the knowledge, and arguably one is better off not worrying about it too much. In contrast with theoretical knowledge, in other words, common sense does not reflect on the world, but instead attempts to deal with it simply “as it is.”6

  The second feature that differentiates common sense from formal knowledge is that while the power of formal systems resides in their ability to organize their specific findings into logical categories described by general principles, the power of common sense lies in its ability to deal with every concrete situation on its own terms. For example, it is a matter of common sense that what we wear or do or say in front of our boss will be different from how we behave in front of our friends, our parents, our parents’ friends, or our friends’ parents. But whereas a formal system of knowledge would try to derive the appropriate behavior in all these situations from a single, more general “law,” common sense just “knows” what the appropriate thing to do is in any particular situation, without knowing how it knows it.7 It is largely for this reason, in fact, that commonsense knowledge has proven so hard to replicate in computers—because, in contrast with theoretical knowledge, it requires a relatively large number of rules to deal with even a small number of special cases. Let’s say, for example, that you wanted to program a robot to navigate the subway. It seems like a relatively simple task. But as you would quickly discover, even a single component of this task such as the “rule” against asking for another person’s subway seat turns out to depend on a complex variety of other rules—about seating arrangements on subways in particular, about polite behavior in public in general, about life in crowded cities, and about general-purpose norms of courteousness, sharing, fairness, and ownership—that at first glance seem to have little to do with the rule in question.

  Attempts to formalize commonsense knowledge have all encountered versions of this problem—that in order to teach a robot to imitate even a limited range of human behavior, you would have to, in a sense, teach it everything about the world. Short of that, the endless subtle distinctions between the things that matter, the things that are supposed to matter but don’t, and the things that may or may not matter depending on other things, would always eventually trip up even the most sophisticated robot. As soon as it encountered a situation that was slightly different from those you had programmed it to handle, it would have no idea how to behave. It would stick out like a sore thumb. It would always be screwing up.8

  People who lack common sense are a bit like the hapless robot in that they never seem to understand what it is that they should be paying attention to, and they never seem to understand what it is that they don’t understand. And for exactly the same reason that programming robots is hard, it’s surprisingly hard to explain to someone lacking in common sense what it is that they’re doing wrong. You can take them back through various examples of when they said or did the wrong thing, and perhaps they’ll be able to avoid making exactly those errors again. But as soon as anything is different, they’re effectively back to square one. We had a few cadets like that at the academy: otherwise perfectly intelligent, competent people who just couldn’t seem to figure out how to play the game. Everyone knew who they were, and everyone could see that they just didn’t get it. But because it wasn’t exactly clear what it was that they didn’t get, we were unable to help them. Bewildered and overwhelmed, most of them eventually left.

  NOT COMMON AT ALL

  As remarkable as it is, common sense exhibits some mysterious quirks, one of the most striking of which is how much it varies over time, and across cultures. Several years ago, for example, an enterprising group of economists and anthropologists set out to test how different cultures play a particular kind of game, called an ultimatum game. The game goes something like this: First, pick two people and give one of them $100. That person then has to propose a split of the money between himself and the other player, ranging from offering them the whole amount to nothing at all. The other player then gets to accept the deal or reject it. If the second player accepts the deal, they get what they were offered and both players go on their merry way. But if they reject the offer, neither player gets anything; hence the “ultimatum.”

  In hundreds of these experiments conducted in industrialized societies, researchers had already demonstrated that most players propose a fifty-fifty split, and offers of less than $30 are typically rejected. Economists find this behavior surprising because it conflicts with their standard notion of economic rationality. Even a single dollar, the reasoning goes, is better than nothing at all, so from a strictly rational perspective, recipients ought to accept any offer above zero. And knowing this, rational “proposers” ought to offer the least they can get away with—namely, one dollar. Of course, a moment’s thought quickly suggests why people play the way they do—namely that it doesn’t seem fair to exploit a situation just because you can. Recipients being offered less than a third therefore feel taken advantage of and so opt to walk away from even a substantial sum of money in order to teach miserly proposers a lesson. And anticipating this response, proposers tend to offer what they assume the recipient will consider a fair split.

  If your reaction to this breakthrough insight is that economists need to get out a little more, then you’re not alone. If anything seems like common sense, it’s that people care about fairness as well as money—sometimes even more so. But when the experimenters replicated the game in fifteen small-scale preindustrial societies across five continents, they found that people in different societies have very different ideas about what counts as fair. At one extreme, the Machiguenga tribe of Peru tended to offer only about a quarter of the total amount, and virtually no offers were refused. At the other extreme, the Au and Gnau tribes of Papua New Guinea tended to make offers that were even better than fifty-fifty, but surprisingly these “hyperfair” offers tended to get rejected just as frequently as unfair offers.9

  What explains these differences? As it turns out, the Au and Gnau tribes had long-established customs of gift exchange, according to which receiving a gift obligates the receiver to reciprocate at some point in the future. Because there was no equivalent of the ultimatum game in the Au or Gnau societies, they simply “mapped” the unfamiliar interaction onto the most similar social exchange they could think of—which happened to be gift exchange—and responded accordingly. Thus what might have seemed like free money to a Western participant looked to an Au or Gnau participant very much like an unwanted obligation. The Machiguenga, by contrast, live in a society in which the only relationship bonds that carry any expectation of loyalty are with immediate family members. When playing the ultimatum game with a stranger, therefore, Machiguenga participants—again mapping the unfamiliar onto the familiar—saw little obligation to make fair offers, and experienced very little of the resentment that would well up in a Western player upon being presented with a split that was patently unequal. To them, even low offers were seen as a good deal.

  Once you understand these features of Au, Gnau, and Machiguenga cultures, their puzzling behavior starts to seem entirely reasonable—commonsense even. And that’s exactly what it was. Just as we reflexively regard fairness and reciprocity as commonsense principles in our world that should be respected in general, and should be defended when violated without good reason, so the people of the fifteen preindustrial societies have their own implicit set of understandings about how the world is supposed to work. Those understandings might be different from ours. But once they have been accepted, their commonsense logic works in exactly the same way as ours does. It is simply what any reasonable person would do if they had grown up in that cu
lture.

  What these results reveal is that common sense is “common” only to the extent that two people share sufficiently similar social and cultural experiences. Common sense, in other words, depends on what the sociologist Harry Collins calls collective tacit knowledge, meaning that it is encoded in the social norms, customs, and practices of the world.10 According to Collins, the acquisition of this type of knowledge can be learned only by participating in society itself—and that’s why it is so hard to teach to machines. But it also means that even among humans, what seems reasonable to one might seem curious, bizarre, or even repugnant to another. For example, as Clifford Geertz, the anthropologist, has described, the treatment of hermaphroditic children has varied dramatically across different times and cultures. The Romans abhorred and killed them; the Greeks tolerated them; the Navajo revered them; and the east African Pokot tribe regarded them simply as “mistakes,” to be kept around or discarded in the same way they might keep or throw out a flawed pot.11 Likewise, practices including human slavery, sacrifice, cannibalism, foot binding, and female genital mutilation that are reviled in most contemporary cultures have all been (and in some cases, still are) considered entirely legitimate in different times and places.

  Another important consequence of the socially embedded nature of common sense is that disagreements over matters of common sense can be surprisingly difficult to resolve. For example, it may seem remarkable to people who have grown up with the impression that New York is a crime-ridden cesspool, or at the very least a cold, hard-edged city full of people you can’t trust, that, according to a recent news story, there is a small cadre of Manhattan residents who don’t lock their doors. As the article makes clear, most people in the city think that the “no lock people” are crazy. As one woman said, “I live in a high-rise with a doorman, I’ve been there fifteen years, and I’ve never heard of a burglary in the building. But that has absolutely nothing to do with it—it’s common sense [to lock your door].” Yet the only thing that seems shocking to the people who don’t lock their doors is that anyone else would be shocked by it.12