(from Latin “liquid,” or “fluid”), in early Western physiological theory, one of the four fluids of the body that were thought to determine a person's temperament and features. In the ancient physiological theory still current in the European Middle Ages and later, the four cardinal humours were blood, phlegm, choler (yellow bile), and melancholy (black bile); the variant mixtures of these humours in different persons determined their “complexions,” or “temperaments,” their physical and mental qualities, and their dispositions. The ideal person had the ideally proportioned mixture of the four; a predominance of one produced a person who was sanguine (Latin sanguis, “blood”), phlegmatic, choleric, or melancholic. Each complexion had specific characteristics, and the words carried much weight that they have since lost: e.g., the choleric man was not only quick to anger but also yellow-faced, lean, hairy, proud, ambitious, revengeful, and shrewd. By extension, “humour” in the 16th century came to denote an unbalanced mental condition, a mood or unreasonable caprice, or a fixed folly or vice.

communication in which the stimulus produces amusement.

In all its many-splendoured varieties, humour can be simply defined as a type of stimulation that tends to elicit the laughter reflex. Spontaneous laughter is a motor reflex produced by the coordinated contraction of 15 facial muscles (muscle) in a stereotyped pattern and accompanied by altered breathing. Electrical stimulation of the main lifting muscle of the upper lip, the zygomatic major, with currents of varying intensity produces facial expressions ranging from the faint smile through the broad grin to the contortions typical of explosive laughter.

The laughter and smile of civilized man is, of course, often of a conventional kind, in which voluntary intent substitutes for, or interferes with, spontaneous reflex activity; this article is concerned, however, only with the latter. Once laughter is realized to be a humble reflex, several paradoxes must be faced. Motor reflexes, such as the contraction of the pupil of the eye in dazzling light, are simple responses to simple stimuli whose value to survival is obvious. But the involuntary contraction of 15 facial muscles, associated with certain irrepressible noises, strikes one as an activity without any utilitarian value, quite unrelated to the struggle for survival. Laughter is a reflex but unique in that it has no apparent biological purpose. One might call it a luxury reflex. Its only function seems to be to provide relief from tension.

The second related paradox is a striking discrepancy between the nature of the stimulus and that of the response in humorous transactions. When a blow beneath the kneecap causes an automatic upward kick, both “stimulus” and “response” function on the same primitive physiological level, without requiring the intervention of the higher mental functions. But that such a complex mental activity as reading a comic story should cause a specific reflex contraction of the facial muscles is a phenomenon that has puzzled philosophers since Plato. There is no clear-cut, predictable response that would tell a lecturer whether he has succeeded in convincing his listeners; but, when he is telling a joke, laughter serves as an experimental test. Humour is the only form of communication in which a stimulus on a high level of complexity produces a stereotyped, predictable response on the physiological reflex level. Thus the response can be used as an indicator for the presence of the elusive quality that is called humour—as the click of the Geiger counter is used to indicate the presence of radioactivity. Such a procedure is not possible in any other form of art; and, since the step from the sublime to the ridiculous is reversible, the study of humour provides clues for the study of creativity in general.

This article deals with the changing concepts and practice of humour from the time of Aristotle to the influence of the mass media in the contemporary world.

The range of laughter-provoking experiences is enormous, from physical tickling to mental titillations of the most varied kinds. There is unity in this variety, however, a common denominator of a specific and specifiable pattern that reflects the “logic” or “grammar” of humour, as it were. A few examples will help to unravel that pattern.

Is there a common pattern underlying these five stories? Starting with the last, a little reflection reveals that the marquis's behaviour is both unexpected and perfectly logical—but of a logic not usually applied to this type of situation. It is the logic of the division of labour, governed by rules as old as human civilization. But his reactions would have been expected to be governed by a different set of rules—the code of sexual morality. It is the sudden clash between these two mutually exclusive codes of rules—or associative contexts—that produces the comic effect. It compels the listener to perceive the situation in two self-consistent but incompatible frames of reference at the same time; his mind has to operate simultaneously on two different wavelengths. While this unusual condition lasts, the event is not only, as is normally the case, associated with a single frame of reference but “disociated” with two. The word disociation was coined by the present writer to make a distinction between the routines of disciplined thinking within a single universe of discourse—on a single plane, as it were—and the creative types of mental activity that always operate on more than one plane. In humour, both the creation of a subtle joke and the re-creative act of perceiving the joke involve the delightful mental jolt of a sudden leap from one plane or associative context to another.

Turning to the other examples, in the French film dialogue, the daughter's “hand” is perceived first in a metaphorical frame of reference, then suddenly in a literal, bodily context. The doctor thinks in terms of abstract, statistical probabilities, the rules of which are inapplicable to individual cases; and there is an added twist because, in contrast to what common sense suggests, the patient's odds of survival are unaffected by whatever happened before; they are still one against 10. This is one of the profound paradoxes of the theory of probability, and the joke in fact implies a riddle; it pinpoints an absurdity that tends to be taken for granted. As for the lady who looks upon death as “eternal bliss” and at the same time “an unpleasant subject,” she epitomizes the common human predicament of living in the divided house of faith and reason. Here again the simple joke carries unconscious overtones and undertones, audible to the inner ear alone.

The masochist who punishes himself by depriving himself of his daily punishment is governed by rules that are a reversal of those of normal logic. (A pattern can be constructed in which both frames of reference are reversed: “A sadist is a person who is kind to a masochist.”) But there is again an added twist. The joker does not really believe that the masochist takes his hot shower as a punishment; he only pretends to believe it. irony is the satirist's (satire) most effective weapon; it pretends to adopt the opponent's ways of reasoning in order to expose their implicit absurdity or viciousness.

The common pattern underlying these stories is the perceiving of a situation in two self-consistent but mutually incompatible frames of reference or associative contexts. This formula can be shown to have a general validity for all forms of humour and wit, some of which will be discussed below. But it covers only one aspect of humour—its intellectual structure. Another fundamental aspect must be examined—the emotional dynamics that breathe life into that structure and make a person laugh, giggle, or smirk.

When a comedian tells a story, he deliberately sets out to create a certain tension in his listeners, which mounts as the narrative progresses. But it never reaches its expected climax. The punch line, or point, acts as a verbal guillotine that cuts across the logical development of the story; it debunks the audience's dramatic expectations. The tension that was felt becomes suddenly redundant and is exploded in laughter. Replace aggression by sympathy and the same situation—a drunk falling on his face, for example—will be no longer comic but pathetic and will evoke not laughter but pity. It is the aggressive element, the detached malice of the comic impersonator, that turns pathos into bathos, tragedy into travesty. Malice may be combined with affection in friendly teasing; and the aggressive component in civilized humour may be sublimated or no longer conscious. But in jokes that appeal to children and primitive people, cruelty and boastful self-assertiveness are much in evidence. To put it differently, laughter disposes of emotive excitations that have become pointless and must somehow be worked off along physiological channels of least resistance; and the function of the “luxury reflex” is to provide these channels.

A glance at the caricatures of the 18th-century English artists William Hogarth (Hogarth, William) or Thomas Rowlandson (Rowlandson, Thomas), showing the brutal merriment of people in a tavern, makes one realize at once that they are working off their surplus of adrenalin by contracting their face muscles into grimaces, slapping their thighs, and breathing in puffs through the half-closed glottis. Their flushed faces reveal that the emotions disposed of through these safety valves are brutality, envy, sexual gloating. In cartoons (cartoon) by the 20th-century American James Thurber (Thurber, James), however, coarse laughter yields to an amused and rarefied smirk: the flow of adrenalin has been distilled and crystallized into a grain of Attic salt—a sophisticated joke. The word witticism is derived from “wit” in its original sense of intelligence and acumen (as is Witz in German). The domains of humour and of ingenuity are continuous, without a sharp boundary: the jester is brother to the sage. Across the spectrum of humour, from its coarse to its subtle forms, from practical joke to brainteaser, from jibe to irony, from anecdote to epigram, the emotional climate shows a gradual transformation. The emotion discharged in coarse laughter is aggression (aggressive behaviour) robbed of its purpose. The jokes small children enjoy are mostly scatological; adolescents of all ages gloat on vicarious sex. The sick joke trades on repressed sadism, satire on righteous indignation. There is a bewildering variety of moods involved in different forms of humour, including mixed or contradictory feelings; but whatever the mixture, it must contain a basic ingredient that is indispensable: an impulse, however faint, of aggression or apprehension. It may appear in the guise of malice, contempt, the veiled cruelty of condescension, or merely an absence of sympathy with the victim of the joke—a momentary anesthesia of the heart, as the French philosopher Henri Bergson (Bergson, Henri) put it.

In the subtler types of humour, the aggressive tendency may be so faint that only careful analysis will detect it, like the presence of salt in a well-prepared dish—which, however, would be tasteless without it. In 1961 a survey carried out among American children aged eight to 15 made the researchers conclude that the mortification, discomfort, or hoaxing of others readily caused laughter, but witty or funny remarks often passed unnoticed.

Similar considerations apply to the historically earlier forms and theories of the comic. In Aristotle's (Aristotle) view, laughter was intimately related to ugliness and debasement. Cicero (Cicero, Marcus Tullius) held that the province of the ridiculous lay in a certain baseness and deformity. Descartes (Descartes, René) believed that laughter was a manifestation of joy mixed with surprise or hatred or both. In Francis Bacon's (Bacon, Francis, Viscount Saint Alban (or Albans), Baron of Verulam) list of what causes laughter, the first place is again given to deformity. One of the most frequently quoted utterances on the subject is this definition in Thomas Hobbes's (Hobbes, Thomas) Leviathan (1651):

In the 19th century, Alexander Bain (Bain, Alexander), an early experimental psychologist, thought along the same lines:

In Bergson's view, laughter is the corrective punishment inflicted by society upon the unsocial individual: “In laughter we always find an unavowed intention to humiliate and consequently to correct our neighbour.” Sir Max Beerbohm (Beerbohm, Sir Max), the 20th-century English wit, found “two elements in the public's humour: delight in suffering, contempt for the unfamiliar.” The American psychologist William McDougall (McDougall, William) believed that “laughter has been evolved in the human race as an antidote to sympathy, a protective reaction shielding us from the depressive influence of the shortcomings of our fellow men.”

However much the opinions of the theorists differ, on this one point nearly all of them agree: that the emotions discharged in laughter always contain an element of aggressiveness. It must be borne in mind, however, that aggression and apprehension are twin phenomena, so much so that psychologists are used to talking of “aggressive–defensive (defense mechanism) impulses.” Accordingly, one of the typical situations in which laughter occurs is the moment of sudden cessation of fear caused by some imaginary danger. Rarely is the nature of laughter as an overflow of redundant tensions more strikingly manifested than in the sudden change of expression on a small child's face from anxious apprehension to the happy laughter of relief. This seems to be unrelated to humour; yet a closer look reveals in it the same logical structure as in the joke: the wildly barking little dog was first perceived by the child in a context of danger, then discovered to be a harmless pup; the tension has suddenly become redundant and is spilled.

Immanuel Kant (Kant, Immanuel) realized that what causes laughter is “the sudden transformation of a tense expectation into nothing.” Herbert Spencer (Spencer, Herbert), the 19th-century English philosopher, took up the idea and attempted to formulate it in physiological (physiology) terms: “Emotions and sensations tend to generate bodily movements. . . . When consciousness is unawares transferred from great things to small,” the “liberated nerve force” will expend itself along channels of least resistance—the bodily movements of laughter. Freud incorporated Spencer's theory of humour into his own, with special emphasis on the release of repressed emotions in laughing; he also attempted to explain why the excess energy should be worked off in that particular way:

In other words, the muscle contractions of the smirk, as the earliest expressions of relief from tension, would thereafter serve as channels of least resistance. Similarly, the explosive exhalations of laughter seem designed to “puff away” surplus tension in a kind of respiratory gymnastics, and agitated gestures obviously serve the same function.

It may be objected that such massive reactions often seem quite out of proportion to the slight stimulations that provoke them. But it must be borne in mind that laughter is a phenomenon of the trigger-releaser type, where a sudden turn of the tap may release vast amounts of stored emotions, derived from various, often unconscious, sources: repressed sadism, sexual tumescence, unavowed fear, even boredom. The explosive laughter of a class of schoolboys at some trivial incident is a measure of their pent-up resentment during a boring lecture. Another factor that may amplify the reaction out of all proportion to the comic stimulus is the social infectiousness that laughter shares with other emotive manifestations of group behaviour.

Laughter or smiling may also be caused by stimulations that are not in themselves comic but signs or symbols deputizing for well-established comic patterns—such as Charlie Chaplin's oversized shoes or Groucho Marx's cigar—or catchphrases, or allusions to family jokes. To discover why people laugh requires, on some occasions, tracing back a long, involved thread of associations to its source. This task is further complicated by the fact that the effect of such comic symbols—in a cartoon or on the stage—appears to be instantaneous, without allowing time for the accumulation and subsequent discharge of “expectations” and “emotive tensions.” But here memory comes into play, having already accumulated the required emotions in past experiences, acting as a storage battery whose charge can be sparked off at any time: the smirk that greets Falstaff's appearance on the scene is derived from a mixture of memories and expectations. Besides, even if a reaction to a cartoon appears to be instantaneous, there is always a process in time until the reader “sees the joke”; the cartoon has to tell a story even if it is telescoped into a few seconds. All of this shows that to analyze humour is a task as delicate as analyzing the composition of a perfume with its multiple ingredients, some of which are never consciously perceived while others, when sniffed in isolation, would make one wince.

In this article there has been a discussion first of the logical structure of humour and then of its emotional dynamics. Putting the two together, the result may be summarized as follows: the “disociation” of a situation or idea with two mutually incompatible contexts in a person's mind and the resulting abrupt transfer of his train of thought from one context to another put a sudden end to his “tense expectations”; the accumulated emotion, deprived of its object, is left hanging in the air and is discharged in laughter. Upon hearing that the marquis in the story told earlier walks to the window and starts blessing the people in the street, the intellect turns a somersault and enters with gusto into the new game. The malicious and erotic feelings aroused by the start of the story, however, cannot be fitted into the new context; deserted by the nimble intellect, these feelings gush out in laughter like air from a punctured tire.

To put it differently: people laugh because their emotions have a greater inertia and persistence than their thoughts. Affects are incapable of keeping step with reasoning (reason); unlike reasoning, they cannot “change direction” at a moment's notice. To the physiologist, this is self-evident since emotions operate through the genetically old, massive sympathetic nervous system and its allied hormones, acting on the whole body, while the processes of conceptual thinking are confined to the neocortex at the roof of the brain. Common experience provides daily confirmation of this dichotomy. People are literally “poisoned” by their adrenal humours; it takes time to talk a person out of a mood; fear and anger show physical aftereffects long after their causes have been removed. If man were able to change his moods as quickly as his thoughts, he would be an acrobat of emotion; but since he is not, his thoughts and emotions frequently become dissociated. It is emotion deserted by thought that is discharged in laughter. For emotion, owing to its greater mass momentum, is, as has been shown, unable to follow the sudden switch of ideas to a different type of logic; it tends to persist in a straight line. Aldous Huxley (Huxley, Aldous) once wrote:

A third alternative is to laugh at people. There are other outlets for tame aggression, such as competitive sports or literary criticism; but they are acquired skills, whereas laughter is a gift of nature, included in man's native equipment. The glands that control his emotions reflect conditions at a stage of evolution (human evolution) when the struggle for existence was more deadly than at present—and when the reaction to any strange sight or sound consisted in jumping, bristling, fighting, or running. As security and comfort increased in the species, new outlets were needed for emotions that could no longer be worked off through their original channels, and laughter is obviously one of them. But it must be borne in mind that laughter is a phenomenon of the trigger-releaser type, where a sudden turn of the tap may release vast amounts of stored emotions, derived from various, often unconscious, sources: repressed sadism, sexual tumescence, unavowed fear, even boredom. The explosive laughter of a class of schoolboys at some trivial incident is a measure of their pent-up resentment during a boring lecture. Not before thinking became gradually detached from feeling could man perceive his own emotion as redundant and make the smiling admission, “I have been fooled.”

The foregoing discussion was intended to provide the tools for dissecting and analyzing any specimen of humour. The procedure is to determine the nature of the two (or more) frames of reference whose collision gives rise to the comic effect—to discover the type of logic or “rules of the game” that govern each. In the more sophisticated type of joke, the logic is implied and hidden, and the moment it is stated in explicit form, the joke is dead. Unavoidably, the section that follows will be strewn with cadavers.

Max Eastman (Eastman, Max), in Enjoyment of Laughter (1936), remarked of a laboured pun by Ogden Nash: “It is not a pun but a punitive expedition.” That applies to most puns, including Milton's (Milton, John) famous lines about the Prophet Elijah's ravens, which were “though ravenous taught to abstain from what they brought,” or the character mentioned by Freud, who calls the Christmas season the “alcoholidays.” Most puns strike one as atrocious, perhaps because they represent the most primitive form of humour; two disparate strings of thought tied together by an acoustic knot. But the very primitiveness of such association based on pure sound (“hol”) may account for the pun's immense popularity with children and its prevalence in certain types of mental disorder (“punning mania”).

From the play on sounds—puns and Spoonerisms—an ascending series leads to the play on words and so to the play on ideas. When Groucho Marx says of a safari in Africa, “We shot two bucks, but that was all the money we had,” the joke hinges on the two meanings of the word buck. It would be less funny without the reference to Groucho, which evokes a visual image instantly arousing high expectations. The story about the marquis above may be considered of a superior type of humour because it plays not on mere words but on ideas.

It would be quite easy—and equally boring—to draw up a list in which jokes and witticisms are classified according to the nature of the frames of reference whose collision creates the comic effect. A few have already been mentioned: metaphorical versus literal meaning (the daughter's “hand”); professional versus common sense logic (the doctor); incompatible codes of behaviour (the marquis); confrontations of the trivial and the exalted (“eternal bliss”); trains of reasoning travelling, happily joined together, in opposite directions (the sadist who is kind to the masochist). The list could be extended indefinitely; in fact any two frames of reference can be made to yield a comic effect of sorts by hooking them together and infusing a drop of malice into the concoction. The frames may even be defined by such abstract concepts as “time” and “weather”: the absent-minded professor who tries to read the temperature from his watch or to tell the time from the thermometer is comic in the same way as a game of table tennis played with a soccer ball or a game of rugby played with a table tennis ball. The variations are infinite, the formula remains the same.

Jokes and anecdotes have a single point of culmination. The literary forms of sustained humour, such as the picaresque novel, do not rely on a single effect but on a series of minor climaxes. The narrative moves along the line of intersection of contrasted planes, such as the fantasy world of Don Quixote and the cunning horse sense of Sancho Panza, or is made to oscillate between them. As a result, tension is continuously generated and discharged in mild amusement.

Comic verse thrives on the melodious union of incongruities, such as the “cabbages and kings” in Lewis Carroll's (Carroll, Lewis) “The Walrus and the Carpenter,” and particularly on the contrast between lofty form and flat-footed content. Certain metric (metre) forms associated with heroic poetry, such as the hexameter or Alexandrine, arouse expectations of pathos, of the exalted; to pour into these epic molds some homely, trivial content—“beautiful soup, so rich and green/ waiting in a hot tureen”—is an almost infallible comic device. The rolling rhythms of the first lines of a limerick that carry, instead of a mythical hero such as Hector or Achilles, a young lady from Ohio for a ride make her ridiculous even before the expected calamities befall her. Instead of a heroic mold, a soft lyrical one may also pay off:

Another type of incongruity between form and content yields the bogus proverb: “The rule is: jam tomorrow and jam yesterday—but never jam today.” Two contradictory statements have been telescoped into a line whose homely, admonitory sound conveys the impression of a popular adage. In a similar way, nonsense verse achieves its effect by pretending to make sense, by forcing the reader to project meaning into the phonetic pattern of the jabberwocky, as one interprets the ink blots in a Rorschach test.

The satire is a verbal caricature that shows a deliberately distorted image of a person, institution, or society. The traditional method of the caricaturist is to exaggerate those features he considers to be characteristic of his victim's personality and to simplify by leaving out everything that is not relevant for his purpose. The satirist uses the same technique, and the features of society he selects for magnification are, of course, those of which he disapproves. The result is a juxtaposition, in the reader's mind, of his habitual image of the world in which he moves and its absurd reflection in the satirist's distorting mirror. He is made to recognize familiar features in the absurd and absurdity in the familiar. Without this double vision the satire would be humourless. If the human Yahoos were really such evil-smelling monsters as Gulliver's Houyhnhnm hosts claim, then Jonathan Swift's (Swift, Jonathan) Gulliver's Travels (1726) would not be a satire but the statement of a deplorable truth. Straight invective is not satire; satire must deliberately overshoot its mark.

A similar effect is achieved if, instead of exaggerating the objectionable features, the satirist projects them by means of the allegory onto a different background, such as an animal society. A succession of writers, from the ancient Greek dramatist Aristophanes through Swift to such 20th-century satirists as Anatole France (France, Anatole) and George Orwell (Orwell, George), have used this technique to focus attention on deformities of society that, blunted by habit, are taken for granted.

The coarsest type of humour is the practical joke: pulling away the chair from under the dignitary's lowered bottom. The victim is perceived first as a person of consequence, then suddenly as an inert body subject to the laws of physics: authority is debunked by gravity, mind by matter; man is degraded to a mechanism. Goose-stepping soldiers acting like automatons, the pedant behaving like a mechanical robot, the Sergeant Major attacked by diarrhea, or Hamlet getting the hiccups—all show man's lofty aspirations deflated by his all-too-solid flesh. A similar effect is produced by artifacts that masquerade as humans: Punch and Judy, jack-in-the-box, gadgets playing tricks on their masters as if with calculated malice.

In Henri Bergson's theory of laughter, this dualism of subtle mind and inert matter—he calls it “the mechanical encrusted on the living”—is made to serve as an explanation of all varieties of the comic. In the light of what has been said, however, it would seem to apply only to one type of comic situation among many others.

From the “disociation” of man and machine, there is only a step to the man–animal hybrid. Walt Disney's (Disney, Walt) creations behave as if they were human without losing their animal appearance. The caricaturist follows the reverse procedure by discovering horsey, mousy, or piggish features in the human face.

This leads to the comic devices of imitation, impersonation, and disguise. The impersonator is perceived as himself and somebody else at the same time. If the result is slightly degrading—but only in that case—the spectator will laugh. The comedian impersonating a public personality, two pairs of trousers serving as the legs of the pantomime horse, men disguised as women and women as men—in each case the paired patterns reduce each other to absurdity.

The most aggressive form of impersonation is the parody, designed to deflate hollow pretense, to destroy illusion, and to undermine pathos by harping on the weaknesses of the victim. Wigs falling off, speakers forgetting their lines, gestures remaining suspended in the air: the parodist's favourite points of attack are again situated on the line of intersection between the sublime and the trivial.

Playful behaviour in young animals and children is amusing because it is an unintentional parody of adult behaviour, which it imitates or anticipates. Young puppies are droll because their helplessness, affection, and puzzled expression make them appear more “human” than full-grown dogs; because their growls strike one as impersonations of adult behaviour—like a child in a bowler hat; because the puppy's waddling, uncertain gait makes it a choice victim of nature's practical jokes; because its bodily disproportions—the huge padded paws, Falstaffian belly, and wrinkled brow—give it the appearance of a caricature; and lastly because the observer feels so superior to a puppy. A fleeting smirk can contain many logical ingredients and emotional spices.

Both Cicero (Cicero, Marcus Tullius) and Francis Bacon regarded deformity as the most frequent cause of laughter. Renaissance princes collected dwarfs and hunchbacks for their merriment. It obviously requires a certain amount of imagination and empathy to recognize in a midget a fellow human, who, though different in appearance, thinks and feels much as oneself does. In children, this projective faculty is still rudimentary: they tend to mock people with a stammer or a limp and laugh at the foreigner with an odd pronunciation. Similar attitudes are shown by tribal or parochial societies to any form of appearance or behaviour that deviates from their strict norms: the stranger is not really human; he only pretends to be “like us.” The Greeks used the same word, barbarous, for the foreigner and the stutterer: the uncouth barking sounds the stranger uttered were considered a parody of human speech. Vestiges of this primitive attitude are still found in the curious fact that civilized people accept a foreign accent with tolerance, whereas imitation of a foreign accent strikes them as comic. The imitator's mispronunciations are recognized as mere pretense; this knowledge makes sympathy unnecessary and enables the audience to be childishly cruel with a clean conscience.

Other sources of innocent laughter are situations in which the part and the whole change roles, and attention becomes focussed on a detail torn out of the functional context on which its meaning depended. When the phonograph needle gets stuck, the soprano's voice keeps repeating the same word on the same quaver, which suddenly assumes a grotesquely independent life. The same happens when faulty orthography displaces attention from meaning to spelling, or whenever consciousness is directed at functions that otherwise are performed automatically. The latter situation is well illustrated by the story of the centipede who, when asked in which order he moved his hundred legs, became paralyzed and could walk no more. The self-conscious, awkward youth, who does not know what to do with his hands, is a victim of the paradox of the centipede.

Comedies (comedy) have been classified according to their reliance on situations, manners, or characters. The logic of the last two needs no further discussion; in the first, comic effects are contrived by making a situation participate simultaneously in two independent chains of events with different associative contexts, which intersect through coincidence, mistaken identity, or confusions of time and occasion.

Why tickling should produce laughter remained an enigma in all earlier theories of the comic. As Darwin (Darwin, Charles) was the first to point out, the innate response to tickling is squirming and straining to withdraw the tickled part—a defense reaction designed to escape attacks on vulnerable areas such as the soles of the feet, armpits, belly, and flank. If a fly settles on the belly of a horse, it causes a ripple of muscle contractions across the skin—the equivalent of squirming in the tickled child. But the horse does not laugh when tickled, and the child not always. The child will laugh only—and this is the crux of the matter—when it perceives tickling as a mock attack, a caress in mildly aggressive (aggressive behaviour) disguise. For the same reason, people laugh only when tickled by others, not when they tickle themselves.

Experiments at Yale University on babies under one year revealed the not very surprising fact that they laughed 15 times more often when tickled by their mothers than by strangers; and when tickled by strangers, they mostly cried. For the mock attack must be recognized as being only pretense, and with strangers one cannot be sure. Even with its own mother, there is an ever-so-slight feeling of uncertainty and apprehension, the expression of which will alternate with laughter in the baby's behaviour (child psychology). It is precisely this element of tension between the tickles that is relieved in the laughter accompanying the squirm. The rule of the game is “let me be just a little frightened so that I can enjoy the relief.”

Thus the tickler is impersonating an aggressor but is simultaneously known not to be one. This is probably the first situation in life that makes the infant live on two planes at once, a delectable foretaste of being tickled by the horror comic.

Humour in the visual arts (art) reflects the same logical structures as discussed before. Its most primitive form is the distorting mirror at the fun fair, which reflects the human frame elongated into a column or compressed into the shape of a toad. It plays a practical joke on the victim, who sees the image in the mirror both as his familiar self and as a lump of plasticine that can be stretched and squeezed into any absurd form. The mirror distorts mechanically while the caricaturist does so selectively, employing the same method as the satirist—exaggerating characteristic features and simplifying the rest. Like the satirist, the caricaturist reveals the absurd in the familiar; and, like the satirist, he must overshoot his mark. His malice is rendered harmless by the knowledge that the monstrous potbellies and bowlegs he draws are not real; real deformities are not comic but arouse pity.

The artist, painting a stylized portrait, also uses the technique of selection, exaggeration, and simplification; but his attitude toward the model is usually dominated by positive empathy instead of negative malice, and the features he selects for emphasis differ accordingly. In some character studies by Leonardo da Vinci, Hogarth, or Honoré Daumier (Daumier, Honoré), the passions reflected are so violent, the grimaces so ferocious, that it is impossible to tell whether the works were meant as portraits or caricatures. If one feels that such distortions of the human face are not really possible, that Daumier merely pretended that they exist, then one is absolved from horror and pity and can laugh at his grotesques. But if one feels that this is indeed what Daumier saw in those dehumanized faces, then they are not comic but tragic.

Humour in music is a subject to be approached with diffidence because the language of music ultimately eludes translation into verbal concepts. All one can do is to point out some analogies: a “rude” noise, such as the blast of a trumpet inserted into a passage where it does not belong, has the effect of a practical joke; a singer or an instrument out of tune produces a similar reaction; the imitation of animal sounds, vocally or instrumentally, exploits the technique of impersonation; a nocturne by Chopin transposed into hot jazz or a simple street song performed with Wagnerian pathos is a marriage of incompatibles. These are primitive devices corresponding to the lowest levels of humour; more sophisticated are the techniques employed by Maurice Ravel in La Valse, a parody of the sentimental Viennese waltz, or by Zoltán Kodály in the mock-heroics of his Hungarian folk opera, Háry János. But in comic operas (comic opera) it is almost impossible to sort out how much of the comic effect is derived from the book and how much from the music; and the highest forms of musical humour, the unexpected delights of a lighthearted scherzo by Mozart, defy verbal analysis, unless it is so specialized and technical as to defeat its purpose. Although a “witty” musical passage that springs a surprise on the audience and cheats it of its expectations certainly has the emotion-relieving effect that tends to produce laughter, a concert audience may occasionally smirk but will hardly ever laugh: the emotions evoked by musical humour are of a subtler kind than those of the verbal and visual variety.

The criteria that determine whether a humorous offering will be judged good, bad, or indifferent are partly a matter of period taste and personal preference and partly dependent on the style and technique of the humorist. It would seem that these criteria can be summed up under three main headings: originality, emphasis, and economy.

The merits of originality are self-evident; it provides the essential element of surprise, which cuts across our expectations. But true originality is not very often met either in humour or in other forms of art. One common substitute for it is to increase the tension of the audience by various techniques of suggestive emphasis. The clown's (clown) domain is the rich, coarse type of humour: he piles it on; he appeals to sadistic, sexual, scatological impulses. One of his favourite tricks is repetition of the same situation, the same key phrase. This diminishes the effect of surprise, but it has a tension-accumulating effect: emotion is easily drawn into the familiar channel—more and more liquid is being pumped into the punctured pipeline.

Emphasis on local colour and ethnic peculiararities, such as Scottish or Cockney stories, for example, is a further means to channel emotion into familiar tracks. The Scotsman or Cockney stories must, of course, be a caricature if the comic purpose is to be achieved. In other words, exaggeration and simplification once more appear as indispensible tools to provide emphasis.

In the higher forms of humour, however, emphasis tends to yield to the opposite kind of virtue—economy. Economy, in humour and art, does not mean mechanical brevity but implicit hints instead of explicit statements—the oblique allusion in lieu of the frontal attack. Old-fashioned cartoons (cartoon), such as those featuring the British lion and the Russian bear, hammered their message in; the modern cartoon usually poses a riddle that the reader must solve by an imaginative effort in order to see the joke.

In humour, as in other forms of art, emphasis and economy are complementary techniques. The first forces the offering down the consumer's throat; the second tantalizes to whet his appetite.

Earlier theories of humour, including even those of Bergson (Bergson, Henri) and Freud (Freud, Sigmund), treated it as an isolated phenomenon, without attempting to throw light on the intimate connections between the comic and the tragic, between laughter and crying, between artistic inspiration, comic inventiveness, and scientific discovery. Yet these three domains of creative activity form a continuum with no sharp boundaries between wit and ingenuity, nor between discovery and art.

It has been said that scientific discovery consists in seeing an analogy where nobody has seen one before. When, in the Song of Bernadette, Bernadette compared the Shulamite's neck to a tower of ivory, he saw an analogy that nobody had seen before; when William Harvey compared the heart of a fish to a mechanical pump, he did the same; and when the caricaturist draws a nose like a cucumber, he again does just that. In fact, all the logical patterns discussed above, which constitute a “grammar” of humour, can also enter the service of art or discovery, as the case may be. The pun has structural equivalents in the rhyme and in word games, which range from crossword puzzles to the deciphering of the Rosetta Stone, the key to Egyptian hieroglyphic. The confrontation between diverse codes of behaviour may yield comedy, tragedy, or new psychological insights. The dualism of mind and inert matter is exploited by the practical joker but also provides one of the eternal themes of literature: man as a marionette on strings, manipulated by gods or chromosomes. The man–beast dichotomy is reflected by Walt Disney's cartoon character Donald Duck but also in Franz Kafka's macabre tale The Metamorphosis (1915) and in the psychologist's experiments with rats. The caricature corresponds not only to the artist's character portrait but also to the scientist's diagrams and charts, which emphasize the relevant features and leave out the rest.

Contemporary psychology regards the conscious and unconscious processes underlying creativity in all domains as an essentially combinative activity—the bringing together of previously separate areas of knowledge and experience. The scientist's purpose is to achieve synthesis; the artist aims at a juxtapositionof the familiar and the eternal; the humorist's game is to contrive a collision. And as their motivations differ, so do the emotional responses evoked by each type of creativity: discovery satisfies the exploratory drive; art induces emotional catharsis; humour arouses malice and provides a harmless outlet for it. Laughter has been described as the “Haha reaction”; the discoverer's Eureka cry as the “Aha! reaction”; and the delight of the aesthetic experience as the “Ah . . . reaction.” But the transitions from one to the other are continuous: witticism blends into epigram, caricature into portrait; and whether one considers architecture, medicine, chess, or cookery, there is no clear frontier where the realm of science ends and that of art begins: the creative person is a citizen of both. Comedy and tragedy, laughter and weeping, mark the extremes of a continuous spectrum, and a comparison of the physiology of laughter and weeping yields further clues to this challenging problem. Such considerations, however, lie beyond the terms of reference of the present article.

The San (Bushmen) of the Kalahari desert of South West Africa/Namibia are among the oldest and most primitive inhabitants of the Earth. An anthropologist who made an exhaustive study of them provided a rare glimpse of prehistoric humour:

But the San remained “in good spirits, pleased with the amusement the springbok had given them.” (From Elizabeth Marshall Thomas, The Harmless People; Alfred A. Knopf, New York, 1959.)

Obviously the San, like most primitive people, do not regard animals as sentient beings; the springbok's kicking in his agony appears to them funny because in their view the animal pretends to suffer pain like a human being, though it is incapable of such feelings. The ancient Greeks' attitude toward the stammering barbarian was similarly inspired by the conviction that he is not really human but only pretends to be. The ancient Hebrews' sense of humour seems to have been no less harsh: it has been pointed out that in the Old Testament there are 29 references to laughter, out of which 13 instances are linked with scorn, derision, mocking, and contempt and only two are born of joy.

As laughter emerged from antiquity, it was so aggressive that it has been likened to a dagger. It was in ancient Greece (ancient Greek civilization) that the dagger was transformed into a quill, dripping with poison at first, then diluted and infused with delightfully lyrical and fanciful ingredients. The 5th century BC saw the first rise of humour into art, starting with parodies of Olympian heroics and soon reaching a peak, in some respects unsurpassed to this day, in the comedies of Aristophanes. From here onward, the evolution of humour in the Western world merges with the history of literature and art.

If the overall trend was toward the humanization of humour from primitive to sophisticated forms, there also have been ups and downs reflecting changes in political and cultural climate. George Orwell's satire of the 20th century, for example, is much more savage than that of Jonathan Swift in 18th-century England or of Voltaire in 18th-century France. If the Dark Ages produced works of humorous art, little of it has survived. And under the tyrannies of Hitler in Germany and of Stalin in the Soviet Union, humour was driven underground. Dictators fear laughter more than bombs.

About non-Western varieties of humour, the Westerner is tempted to repeat the middle-aged British matron's remark on watching Cleopatra rave and die on the stage: “How different, how very different from the home life of our dear Queen.” Humour thrives only in its native climate, embedded in its native logic; when one does not know what to expect, one cannot be cheated of one's expectations. Hindu (Hinduism) humour, for instance, as exemplified by the savage pranks played on humans by the monkey-god Hanuman, strikes the Westerner as particularly cruel, perhaps because the Hindu's approach to mythology is fundamentally alien to the Western mind. The humour of the Japanese (Japan), on the other hand, is, from the Western point of view, astonishingly mild and poetical, like weak, mint-flavoured tea:

The following dates from about a century later:

The combination of maudlin tears and brazen selfishness, and the crazy logic of equating the wife's coiffure with a liquid measure of saké, show the familiar Western pattern of the clash of incompatibles, even though transplanted into another culture.

Humour today seems to be dominated by two main factors: the influence of the mass media and the crisis of values affecting a culture in rapid and violent transition. The former tends toward the commercialized manufacture of laughter by popular comedians and gags produced by conveyor-belt methods; the latter toward a sophisticated form of black humour larded with sick jokes, sadism, and sex.

Fashions, however, always run their course; perhaps the next one will delight in variations on the theme of the monkey boss who, having gained possession of the moon, does not know what to do with it. The only certainty regarding the humour of the future is contained in Dr. Samuel Johnson's dictum: “Sir, men have been wise in many different modes, but they have always laughed in the same way.”