The range of modern writing on laughter is truly daunting. My own university library holds around 150 books with "laughter" somewhere in the title, all published in English in the first decade of the 21st century. Leaving aside assorted memoirs, novels, and collections of poetry that managed to squeeze the word into the subtitle (Love, Laughter and Tears in Paris at the World’s Most Famous Cooking School and the like), these books range from popular psychology and self-help manuals, through the philosophy of humor and the anatomy of the joke, to the history of the chuckle, the chortle, the snigger, and the giggle in almost any period or place you can imagine, right back to the origins of laughter in the caves of primitive humans.
Behind these books, both weighty and popular, is an even wider array of specialist articles and papers investigating yet more aspects of the subject, in ever finer detail: the use of laughter in health education films in Dutch colonial Java, the sound of laughter in the novels of James Joyce, that old chestnut of when, and how, babies first start to laugh or smile.
There is, in short, far too much written—and still being written—on the subject of laughter for any one person to master; nor, frankly, would it be worthwhile to try. Confronted with the product of centuries of analysis and investigation, one is tempting to suggest that it is not so much laughter that defines the human species, as Aristotle is supposed to have claimed, but rather the drive to debate and theorize laughter.
Partly in response to the profusion of views and speculation, theories of laughter are typically divided into three main strands. Few books on laughter fail to offer, somewhere near the beginning, a brief enumeration.
The so-called superiority theory argues that laughter is a form of derision or mockery: We laugh at the butt of our jokes or the object of our mirth, and in the process we assert our superiority over them. Aristotle is often supposed to be one main source of this view. Otherwise the most celebrated theorist of superiority is Thomas Hobbes. "The passion of Laughter," he wrote in The Elements of Law, Natural and Politic, "is nothyng else but a suddaine Glory arising from some suddaine Conception of some Eminency in our selves, by Comparison with the Infirmityes of others"—a much-quoted sentence, whose catchphrase "sudden glory" has often been reused, even as the title of a book on the history of laughter.
When someone is being tickled, it is common for observers, too, to laugh. Same laughter, or different?
But superiority theory is not only an aspect of the philosophy and ethics of laughing. Evolutionary biology chimes in, with some reconstruction of laughter’s origins among the earliest humans. One idea, for example, is that laughter derives directly from "the roar of triumph in an ancient jungle duel" or that the laugh (or the smile) originated in an aggressive baring of the teeth.
The second theory, known as the incongruity theory, sees laughter as a response to the illogical or the unexpected. A big team of philosophers and critics can be marshaled as supporters of this idea, if with a wide range of nuances and emphases. Kant argued that "laughter is an affection arising from a strained expectation being suddenly reduced to nothing," another of the better-known sayings in the study of laughter. Henri Bergson argued that laughter is provoked by living beings acting as if they were machines—mechanically, repetitively, stiffly. More recently the linguistic theories of Salvatore Attardo, of Texas A&M University, and Victor Raskin, of Purdue University, have set the resolution of incongruity at the heart of verbal jokes—as in "When is a door not a door? When it’s a jar."
Experimental science has a role here, too. One of the most celebrated experiments in the history of laboratory-based studies of laughter is the weight-discrepancy test. Subjects are asked to lift a series of weights, similar in size and appearance and varying only slightly in heaviness, and to rank them from heaviest to lightest. Then another weight is introduced, similar in appearance but substantially heavier or lighter than the rest. The subjects regularly laugh when they lift the new weight—because, it is argued, of the incongruity between it and the others. In fact, the heavier or lighter the new weight is, the more strongly they laugh: the greater the incongruity, in other words, the more intense the laughter. (I am always surprised that no one dares to suggest that the subjects are actually laughing at the experimenters.)
The last of the trio is the relief theory, best known from the work of Freud but not invented by him. In its simplest, pre-Freudian form, this theory sees laughter as the physical sign of the release of nervous energy or repressed emotion. Rather like the pressure of steam, pent-up anxiety about death, for example, is "let off" when we laugh at a joke about an undertaker.
Freud’s version of this idea is considerably more complicated. In his Jokes and Their Relation to the Unconscious, he argues that the energy released in laughter is not the energy of the repressed emotion itself (the safety-valve model) but the psychic energy that would have been used to repress the thoughts or feelings if the joke had not allowed them to enter our conscious minds. A joke about an undertaker allows our fear of death to be expressed, and the laughter is the "letting off" of the surplus psychic energy that would otherwise have been used to repress it. The more energy it would have taken to repress the fear, the bigger the laugh will be.
These three theories are a convenient shorthand. They bring order to the complicated history of speculation on laughter, and they highlight striking similarities in the way it has been understood across the centuries. Beyond that, however, they run into serious problems—both as individual theories of laughter themselves and as overarching schemes for classifying the field of study as a whole. The theoretical landscape of laughter is much messier than "the theory of the three theories" would suggest. You can see that from the simple fact that the same theorists turn up as representatives of different theories, Bergson sometimes being made to stand for "incongruity" and sometimes for "superiority."
What has made laughter such an intriguing and compelling object of investigation for more than 2,000 years is also what makes it such a tricky and sometimes intractable one. Among the most difficult questions is whether laughter is a unitary phenomenon. Should we even be looking for a single theory, one that can put under the same explanatory umbrella the laughter produced by a hearty tickling and by a good joke, let alone the often rather subdued laughter that regularly punctuates and reinforces human conversation? Scrupulous caution suggests that those are significantly different signals, with different causes and effects. Yet in all kinds of ways, laughter does feel very similar across its different manifestations. Besides, it is often impossible to draw clear boundaries among its various types. When someone is being tickled, it is common for observers, who are not themselves being tickled, to laugh. Same laughter, or different?
Even more crucial is the question of whether laughter is a natural or a cultural phenomenon—or, perhaps better, whether laughter directly challenges the simplicity of that binary division. As the anthropologist Mary Douglas summed it up, "Laughter is a unique bodily eruption which is always taken to be a communication." Unlike sneezing or farting, laughter is taken to mean something. Its ambiguity, between nature and culture, has a tremendous impact on our attempts to understand how laughter in general operates in human society and, more specifically, how far it is under our conscious control. "I couldn’t help laughing," we often say. Is that true?
Some laughter really does seem to be, and feels, uncontrollable—and not only that produced by tickling. As is the case with a television news anchor who cannot prevent herself from corpsing on air, sometimes laughter erupts (or nearly does) whether we want it to or not. Such incidents are presumably what Douglas had in mind. However unwilled the eruptions may be, observers or listeners will still ask themselves what the laugher is laughing at, and what message is being conveyed.
But the idea of laughter’s uncontrollability is more complicated than this story may suggest. Most laughter is relatively easy for the laugher to control. Even the effects of tickling are more subject to social conditions than we imagine: You cannot, for example, produce laughter by tickling yourself (try it!), and if tickling is carried out in a hostile rather than a playful environment, it does not cause laughter. Besides, even the most ticklish sites of the body are differently identified in different cultures and at different times. The underarm is more or less universal, but while we would emphasize the soles of the feet, one member of Aristotle’s school had quite another idea: We are, he claimed, most ticklish "on the lips," because, he went on to explain, the lips are near "the sense organ." Tickling does not, in other words, produce a wholly spontaneous, reflex response.
Laugher is a key marker of what we feel about other cultures, about our own past and the "progress of civilization."
In practice, most people, most of the time, manage to manipulate two strikingly incompatible views of laughter: the myth of its uncontrollability and the everyday experience of laughter as a learned, cultural response. Anyone who has ever brought up young children will remember the time and effort it took to teach them the standard rules of laughter. In simplest terms, what to laugh at and what not to laugh at: clowns, yes; people using wheelchairs, no; The Simpsons, yes; the fat lady on the bus, no.
Another aspect of learning to laugh is found in the cultural specificity of the objects, style, and rhetoric of laughter. Whatever the physiological universals that may be involved, people in different communities, or parts of the world, learn to laugh at different things, on different occasions, and in different contexts (as anyone who has tried to raise a laugh at a conference abroad will readily attest). There is also the matter of how people laugh. Indeed, part of our expectations and stereotypes of foreign cultures is that they laugh differently. Even the most sophisticated theorists can have strikingly rough-and-ready views about these differences. For Nietzsche, Hobbes’s opposition to laughter (giving it a "bad reputation," or bringing it "into disrepute," as another translation puts it) was just what you would expect from an Englishman.
The classic anthropological example of how people laugh differently comes from the Pygmies, of the Ituri Forest, in what is now the Democratic Republic of the Congo. As Mary Douglas described it, not only do the Pygmies "laugh easily" compared with other, more dour and solemn tribes, but they laugh in a distinctive way: "They lie on the ground and kick their legs in the air, panting and shaking in paroxysms of laughter." To us this might seem a flamboyant and contrived display, but the Pygmies have so internalized the conventions of their culture that it is for them "natural."
It is not, however, quite so simple. Pygmy laughter is a convenient example of cultural diversity in the ways that people laugh. But what is the evidence for it? So far as I can tell, the information is derived from just a single source—a best-selling book called The Forest People, by the popular anthropological writer Colin Turnbull. This account was driven by the author’s romantic view of the Pygmies as happy, open, gentle folk, living an idyllic existence, blissfully in harmony with their exotic rain-forest world. Exuberant laughter was just one of the signs of their cheerful life. As Turnbull described it, "When pygmies laugh it is hard not to be affected; they hold onto one another as if for support, slap their sides, snap their fingers, and go through all manner of physical contortions. If something strikes them as particularly funny they will even roll on the ground."
Turnbull was almost certainly an unreliable witness of Pygmy culture. Quite how unreliable we will probably never know. But in any case, the more interesting question is why his testimony on Pygmy laughter should have been so widely repeated, even by scholars such as Douglas, who in other respects would have little time for his brand of anthropology.
It is partly, no doubt, that even the most hardheaded among us are loath to discard this happy, colorful image of the little Pygmy kicking his legs in the air (despite the fact that Turnbull’s description actually stopped short of the kicking). But there are more discursive issues at work here, too. For the behavior of Pygmies, as it is so often told and retold, no longer has much direct relationship with what the real people of the Ituri Forest do, or once did—and still less with why they laughed in that way or with what consequences. Their behavior has become a literary cliché, a shorthand that, in our second-order reflections on laughter, usefully stands for the extreme case of a foreign people who laugh differently. In our own cultural calibration of laughter, the Pygmies have come to mark one end of the spectrum. Nietzsche’s view of Hobbes and the English is a hint of how culturally relative such calibration can be. One wonders how the Pygmies would have described Turnbull’s style of laughter.
The study of laughter—in the present as much as in the past—repeatedly faces the question of where the boundary between literal and metaphorical laughter lies and what the relationship is between them. Sometimes we find it relatively unproblematic to embrace metaphorical readings. If a Roman poet, for example, writes of glittering water or a houseful of flowers "laughing," that is usually taken as a metaphor for the gaiety of the scene rather than as a deep, etymological connection between laughter and "shimmering" or "blooming."
But metaphorical uses of "laughing" also lurk just beneath the surface of some of the most apparently scientific, experimental discussions of laughter. Nowhere is this more striking (or more often neglected) than in the old Aristotelian question of whether human beings are the only animals that laugh.
This has been the subject of much inconclusive scientific investigation, going back at least to Darwin, who was, for obvious reasons, keen to emphasize that chimpanzees appeared to laugh when they were tickled. More-recent scientific observers have identified a characteristic "open-mouth display" or "play face" in primates engaged in nonserious activities, and have occasionally claimed to detect some chimps and gorillas using jokes and puns in their rudimentary sign language. Some biologists, not to mention devoted dog owners, have concluded that there is also such a thing as canine laughter (a conclusion that prompted Douglas’s famous article "Do Dogs Laugh?"). A few researchers have even interpreted the high-pitched chirping that rats produce when they are tickled as a form of proto-laughter; the nape of the neck is said to be one of their most ticklish zones, although they chirp enthusiastically with a "full body" tickle, too.
Unsurprisingly, those interpretations have been contested from many angles. The "laughter" of primates, for example, is articulated differently from that of humans. The universal pattern in humans is for the characteristic "ha ha ha" to be produced in one single exhalation, followed by silence during inhalation. Not so among the primates. Their panting laughter is vocalized during both the in and the out breath. Is this, as some would have it, just a variant on the same spectrum of laughter? Or does it indicate, as others think, that we are dealing with a significantly different type of response—and that primates are not, in our terms, laughing at all? The chirping of rats (which is, incidentally, at such a high frequency that it is inaudible to the human ear) remains even more controversial, with many scientists resisting any connection to human laughter.
But even if we were to concede that similar neural pathways are involved in all of these phenomena, and that there are at least some evolutionary links between rats’ chirping and humans’ chortling, there is a much more pressing question that is almost always sidestepped: What does it mean to say that dogs or apes or rats "laugh"?
Most people would agree that dog owners, in detecting laughter in their pets, are driven by a desire to anthropomorphize and incorporate the animals into the world of human sociality, by projecting onto them that key human characteristic. As Roger Scruton observed, with slightly different emphasis, when we hear hyenas (for example) "laughing" at one another, it is an expression not of their amusement but of ours. Even in the apparently more rigorous discourse of experimental science, the boundary between laughter as a metonym of humanity and laughter as a physical or biological response is a tricky one. Once again we find an important blurring of the simple distinction between nature and culture. For the claim that a rat can "laugh" is liable to imply something more about that species in general, and our relationship with it, than just that the neurons in its brain operate in a particular way.
The pleasure and excitement of studying laughter, for a historian, is that it generates many more questions than answers. Theories of laughter have always been "theories of theories," a way of talking about laughter and "something else." Recent neurological advances in understanding which bits of the brain generate laughter (and how) are, of course, important, and not to be dismissed by decidedly nonexperimental historians.
But in historical terms, culture almost always trumps nature. Laughter has been a key marker of what we feel about other cultures, about our own past and our views of the "progress of civilization." Can you think of a culture that claims to laugh more lustily than its predecessors? Perhaps the French revolutionaries, who wished to transcend the stylized suppression of emotion that went with the monarchy, but what others? Basically, in discursive terms, the regimes and refinement of laughter turn out to be a key marker of human progress (whatever the lusty chortles in the bar). And that is why laughter is such a fertile, and hopefully funny, subject for the historian, simultaneously enriching and frustrating, eye-opening and opaque.
Rident omnes, as the Romans would have said.
Mary Beard is a professor of classics at the University of Cambridge. She is the author, most recently, of Laughter in Ancient Rome: On Joking, Tickling, and Cracking Up (University of California Press), from which this essay is adapted.