More than 100 "theories" of humor have been identified (Schmidt & Williams, 1971). These notions include general theories about humor or laughter, statements of the circumstances in which humor may occur, and characterizations or descriptions. Several important reviews have been provided (Berlyne, 1969; Derks, 1996; Haig, 1988; Piddington, 1933; Sully, 1902) and these are heartily recommended to the reader new to this topic.

One very influential review is that of Patricia Keith-Spiegel (1972), who created a typology of eight categories. The first category consisted of biological theories (e.g., Darwin, 1872), which suggest that humor is an adaptive disposition. The second category consisted of superiority theories (e.g., Hobbes, 1968), which suggest that people laugh at others to whom they feel superior. The third category consisted of incongruity theories (e.g., Kant, 1951), which suggest that humor consists of incongruous events and situations. The fourth category consisted of surprise theories (e.g., Descartes, 1649), which suggest that humor requires suddenness and therefore weakens with repeated exposure. The fifth category consisted of ambivalence theories (e.g., Joubert, 1980) which suggest that humor is the result of opposing emotions or ideas within an appreciator. The sixth category consisted of release theories (e.g., Spencer, 1860), which suggest that humor is experienced when people are relieved from strain or stress. The seventh category consisted of configuration theories (e.g., Maier, 1932), which suggest that humor depends directly on the resolution of incongruities. The eighth category consisted of psychoanalytic theories (e.g., Freud, 1928), which suggest that humor results from economies of psychic energy that has been built up by and for repression.

It is proposed here that these myriad theories can be sorted further into just three groups. The first group (biological, psychoanalytic or relief, and ambivalence theories) consider the function of humor. They try to explain why we laugh and what survival value humor has. The second group (incongruity, surprise, and configuration theories) consider the stimuli for humor. They try to explain what makes funny things funny. The final group (superiority, and the newer cognitive theories) consider our response. They try to explain how and why we find things funny. This grouping will be adopted for the discussion of the theories that follows.

The Function of Humor

In this category of humor theories about the function of the phenomenon, release and relief theories such as Freud's prevail. However, there are also lesser known biological and evolutionary theories, and these will be discussed first. Many of these theories were developed before the distinctive use of the word humor evolved, so they tend to equate humor and laughter.

Has laughter evolved? Evolutionists from Charles Darwin (1872) to Glenn Weisfield (1993) have claimed that laughter is an adaptive behavior. As evidence, they point out that laughter is pervasive in humans, has a fairly early onset (16 weeks), and can be compared with similar behaviors found in related species. The most conclusive evidence for their claim would be the discovery of a specific neural structure or pathway for laughter. Recent work at UCLA Medical School (Fried, Wilson, MacDonald, & Behnke, 1998; Reese, 1998) may be instructive. Specific brain stimulations generated laughter in a patient. She subsequently attributed this laughter to various nearby items, which she insisted were funny. This sort of evidence about laughter makes us wonder if even humor isn't more programmed than we usually image.

However, laughter does not seem to appear in any other species. Laughter (like language) is only possible for those species that learn to walk on two legs (Provine, 1996). This is due to the difficulty of laughing, or speaking, while thumping around on "all fours," something readers are encouraged to try for themselves.

Is humor just a special case of playing? It is generally thought (e.g., Aldis, 1975) that play allows young humans and other animals to rehearse and develop the physical and social skills they will need as adults. Paul McGhee (1979) has argued that humor may have evolved to allow rehearsal and development of the abstract skills that only humans seem to use. Others have argued that laughter allows release of the inevitable tension of living in civilization (e.g., Grumet, 1989) or that humor allows the fantasy and play that lead to new innovations and ways of coping (Christie, 1994). These explanations help us understand why laughter might have evolved uniquely in humans.

The interesting question for these theories is why laughter (or crying for that matter) should be adaptive. Laughter does not resolve problems or situations but instead seems to constitute an alternative to dealing with them. Generally, there are two theories about why laughter can be considered as adaptive.

Some writers have suggested that humor is adaptive because it operates like a circuit breaker, intentionally disabling people and preventing them from continuing misguided behavior patterns (Chafe, 1987). George Milner (1972) said that laughter "breaks us up" when we are being too extreme or taking ourselves too seriously. In a similar way, Marvin Minsky (1984) pointed out that laughter disrupts processing to reveal the absurdity of infinite regressions or other logical errors. Researchers at Leiden University Medical Center in The Netherlands found that laughter reduced the H-reflex (Ben-Ari, 1999). That reduction explained the "weak in the knees" feeling that often accompanies laughter. Gopalaswami (1926) assigned humor a place alongside other natural mechanisms to deal with unsurmountable attacks such as the urge to flee, the cry of appeal or submission, and consciousness-reduction (going into shock) or consciousness-abolition (fainting).

Others, in arguing for the adaptive nature of humor, have focused on the release and purging of emotions that occurs as a result of taking a humorous perspective. Laughter may have developed in humans as a biological mechanism for protecting them against "excessive sympathy" for the problems and misfortunes of others. William McDougall (1922) argued that the psychological burden of empathy would become unbearable without this outlet. The idea that humor prevents us from being overcome with (and disabledd by) emotions has strong intuitive appeal for this author, but has not received much testing or support in the literature to date.

The idea that there is an evolutionary basis for humor is supported by any evidence that humor is beneficial. Here are several beneficial effects of humor, based on a classification scheme developed by Don Nilsen (1993).


One benefit of humor is that it encourages laughter, which seems to have certain physiological benefits. One popular claim, that laughter releases endorphins (e.g.., Bond, 1998; Braverman, 1993; Brooks, 1999; Hulse, 1994; Lea, 1998; Nyhout, 1998; Rapaport & Gibson, 1993), enjoys no scientific support whatever. However, laughter does seem to provide health benefits of the sort that one would expect from jogging. It provides general benefits such as improved respiration (e.g., McGhee, 1998) and specific ones such as improved natural killer cell cytotosicity (Bennett, 1997) and increased levels of secretory immunoglobulin "A" (Perera, Sabin, Nelson, & Lowe, 1998). In fact, it has been found that laughter increases immunity better than relaxation (Burns, 1996).

Norman Cousins (1979) wrote the most-often-misunderstood testimonial to the health benefits of laughter. Even professionals occasionally claim that he was cured of cancer by laughter therapy. This claim is, of course, nonsense. The collagen disorder he suffered was indeed serious, and offered only a one in five hundred chance of remission. Cousins checked out of his hospital and stayed in a more cheery hotel room. He attributed his eventual remission to massive doses of vitamin C (five grams a day) and a liberal application of "Candid Camera" episodes and "Laurel and Hardy" movies.

Although he specifically denied that humor cured anything (Cousins, 1985), and repeatedly reminded his readers that he took every medicine prescribed by his doctors, Cousins did acknowledge that humor provided him with pain-free sleep and even reduced his sedimentation levels (an infection measure) almost as much as the Vitamin C.

Similar claims for the healing power of laughter are found in the writings of physicians and philosophers from the 13th to the 19th century (Goldstein & McGhee, 1972b). Modern research is focusing on documenting the effects of laughter on secretory levels (Kamei, Kumano, & Masumura, 1997; Lambert & Lambert, 1995; Martin & Dobbin, 1988; McClelland & Cheriff, 1997), although it is not yet clear to this author that there is anything about this effect that is unique to humor as against any other engaging emotion.

A second benefit of humor is noted by psychologists. The personality trait called a sense of humor seems to counteract stress (Newman & Stone, 1996) or at least moderate its harmful effects (Kuiper & Martin, 1998; Lefcourt & Thomas, 1998). It has been shown to be associated with positive personality characteristics such as optimism and self-esteem (Thorson, Powell, Sarmany-Schuller, & Hampes, 1997).

Laughter and humor have been found to benefit depressed patients (Thorson & Powell, 1994), people who are grieving (Keltner & Bonanno, 1997), and other clients of both psychotherapists (Chapman & Chapman-Santana, 1995) and psychologists (McGuire, 1999). The use of humor is being cautiously considered by psychoanalysts (Giovacchini, 1999) and has been associated with the capacity for regression in service of the ego (Sands, 1979). Some innovative forms of psycho- therapy such as "Natural High Therapy" (O'Connell, 1981) use and encourage the sense of humor in the treatment. A similar approach was prescribed by Alfred Adler as early as 1929 (Gomez, Gomez, & O'Connell, 1994). The perspective taken by a humorist is one of the detached observer, and it allows clients to consider responses to problems without being overwhelmed by them (Yonkovitz & Matthews, 1998). The use of humor also aids the therapist in challenging the perspectives of clients in cognitive behavioral therapy (Epstein, 1997).

A third benefit of humor is noted by sociologists and anthropologists. The sharing of laughter reflects tolerance, acceptance, and sympathy toward others (Mindess, 1971). Many authors speculate that laughter was originally a vocal sign to other members of the group that they could relax in safety after a perceived threat was vanquished or turned out to be non-threatening (e.g. Hayworth, 1928; Ramachandran, 1998). The ability of humor to build a sense of community (e.g., Hampes, 1992), and especially a diverse community in the workplace (Meyer, 1997), have been demonstrated. Understanding humor presupposes a shared context and this shared context is reinforced within many groups by the use of humor (Zilberg, 1995). Humor also acts as a social lubricant, as when humor is used to gently correct someone's manners while saving face for everyone involved.

Another benefit of humor is of the intellectual sort. The creation and appreciation of humor has long been associated with high intelligence (Galloway, 1994), problem solving (Belanger, Kirkpatrick, & Derks, 1998), creativity (Murdock & Ganim, 1993), generativity (Hampes, 1993), and high verbal ability (Suls, 1972). Humor involves the suspension of the "normal rules" of logic, as does innovation (Humke & Schaefer, 1996) and has been shown to enhance "mental rotation" (Belanger et al., 1998). It is also claimed that humor supports education by reducing anger (Forbes, 1997) and engaging student attention (Prosser Jr., 1997).


Neural research may offer some insight into the functions of humor (e.g., McCrone, 2000). Prathiba Shammi recently demonstrated that people with right frontal lobe damage fail to recognize irony, while still enjoying slapstick humor (Shammi & Stuss, 1999). Of course, this effect may be related more to second-order language comprehension than humor (Winner, Brownell, Happe, Blum, & Pincus, 1998) and it seems to almost duplicate an earlier study (Brownell, Michel, Powelson, & Gardner, 1983). But it is an identification of a brain area that is involved in the decoding of humor.

Positive and negative emotions have traditionally been seen as bipolar, involving the same mechanisms (e.g., Simonov & Mikhailova, 1971). However, they may operate quite differently in the case of humor. Positive responses to incongruity and resolved-incongruity humor operate by arousing neural networks while enjoyment of "tendentious" humor (involving sex or aggression) seems to operate by lowering the threshold of stimulation instead (Katz, 1993). It is not clear whether this sort of explanation challenges other theories or merely demonstrates how they operate, but this is another frontier for scientific research into humor.

Besides the above-noted evolutionary views of humor's purpose and benefits, there are psychoanalytic and ambivalence theories about the function of humor.

Sigmund Freud, following on Herbert Spencer (1860), hypothesized that laughter sprung up from the excess energy created by sexual and aggressive repression (Freud, 1960). He saw humor as a relatively clandestine way of expressing these socially proscribed urges. He divided the topic into three subsections: (a) jokes, which were used to express tendentious material such as sex and aggression, (b) wit, which was used to exercise and celebrate the intellect through word play primarily, and (c) humor, which was used for the good natured sharing of mirth and enjoyment.

Freud understood jokes as a temporary rebellion against the "psychic censors" that monitor sexual and aggressive content, but could not explain the appeal of nonsense humor. Much later, Marvin Minsky (1984) was able to explain nonsense humor as a rebellion against the "logic police." Empirical research tends to confirm Freud's contentions (Redlich, Levine, & Sohler, 1951) and suggest that simple cognitive explanations of the humor process may miss important subconscious aspects (Deleanu, 1983).

Related to Freudian "safety valve" theories of the function of humor are ambivalence theories. They assert that humor acts as a circuit breaker when someone is forced to entertain two strong and opposing emotions at the same time (Hazlitt, 1890). Arthur Koestler (1964) claims that humor occurs when two conflicting perspectives are briefly entertained at the same instant. Marvin Minsky (1984) agrees that two representational frames cannot successfully be entertained at once.

Different authors identify different dichotomies as being at the root of the humor. James Beattie (1778) attributes humor to ambivalence between the suitable and the unsuitable. John Greig (1969) specifies ambivalence between love and fear, expressed in adults as the opposition of sexuality and repression. George Milner (1972) cites the ambivalence between nature and culture. However, while strong emotional ambiguities have been shown to enhance the ferocity of laughter, they do not seem to be essential to the existence of humor. Ambiguity itself does not inevitably lead to humor, as opposed to confusion or anxiety.

The above theories attempt to account for the existence of humor by arguing that humor is adaptive, and could be expected to have been "selected in" over the generations.

Stimulus Theories

In this second category of humor theories, which try to explain what is funny about funny things, it is the various incongruity theories that prevail. However, there are also surprise theories, which suggest that an event must be sudden in order to be humorous.

While surprise is a ubiquitous quality of humor (especially in the punch lines of jokes), it does not seem essential (van Thriel & Ruch, 1993). People often laugh at the same ludicrous thing (such as a favorite comedy routine) long after the surprise has gone (Nilsen, 1990). Not only is surprise not always present in humor, but some have even questioned whether any sort of "shift" is necessary for humor (Roberts, 1987). It seems that surprise is not essential to the experience of humor.

Incongruity, however, looks like a better candidate for an essential ingredient of humor (e.g., Wicker, Thorelli, Baron III, & Ponder, 1981). There are many incongruity theories, all of which state in various ways that humor consists of the juxtaposition of the incongruous.

Some research, undertaken originally to examine surprise theories, seemed to show that incongruity alone (at an appropriate level) was sufficient for humor. (Deckers & Winters, 1986; Nerhardt, 1996). Participants lifted several weights, each about as heavy as the last. Then a weight much heavier (or much lighter) was introduced. Lifting these incongruous weights generated bursts of laughter. Using the FACS or Facial Action Coding System (Ekman & Friesen, 1978) , a direct relationship between the size of the discrepancy and the amount/intensity of smiling/ laughter was recorded (Koehler, 1993). Although such experiments tend to equate humor with laughter and/or smiling, they also seem to suggest that the effect can be generated by incongruity alone (Deckers, 1993; Wicker et al., 1981).

However, many incongruity theorists disagree that incongruity alone is sufficient for laughter, especially amongst adults. Tom Shultz (1972) found that children under seven would laugh at a simple incongruity but that older children required a surprising resolution of that incongruity before finding something funny. Although his findings were confounded by humor that required relatively sophisticated language skills, the same point can be illustrated with a simple joke.

W. C. Fields was supposedly asked if he approved of social clubs for children. If he had answered, "Why, yes I do," that would not have been incongruous and therefore would not have been funny. If he had answered, "Elephants are people, too," that would have been incongruous, but would not likely strike anyone over the age of seven as very funny. If he had answered, "Only when kindness fails," that would seem at first incongruous. However it would soon be resolved by remembering that Fields disliked children, and by seeing that he (pretended to) mistake the word club as referring to a long wooden stick. Clearly it is the resolution of the incongruity that is funny in this example.

Advocates of the incongruity-resolution view feel that they can explain Decker's results with weight disparity in this way. Although the sudden unexpected heaviness (or lightness) of a new weight at first seemed incongruous, the incongruity was soon resolved by the subjects. They realized either that it was all just a joke, or that their original expectations had never really been justified. This view is favored by the Gestalt psychologists such as Norman Maier (1932), Gregory Bateson (1953), and Bateson's students, including the seminal modern humor scholar Bill Fry, Jr. (1963). Their claim is that incongruity is necessary but not sufficient for humor.

In general, scholars believe that humor is a necessary condition for humor stimuli. But some writers, such as Tomas Kulka (1990) and Robert Latta (1998), reject incongruity theories altogether. They argue that incongruity theories point to a ubiquitous quality of humor stimuli, but cannot account for either the aesthetic enjoyment of incongruity or the pleasurable affective response that it seems to generate. To respond to these criticisms, it is necessary to look at theories that go beyond the humor stimulus.

Response Theories

In the final category of humor theories, about when an appreciator will be amused, it is the superiority theories that prevail. These will be discussed first, then the contribution of newer cognitive theories will be assessed.

Superiority theories are the oldest theories of humor. Partly because of this, and given that our use of the term humor is only about four hundred years old, most of these theories equivocate between laughter (the behavior) and humor (the phenomenon).

Plato considered laughter to be a form of malice, usually aimed at self-delusion in relatively powerless people (Plato, 1906). He worried that it caused people to lose rational control of themselves. He thought that any reference to gods laughing should be censored from mythology so as not to portray the gods as being out of control.

Aristotle later agreed that a joke was a tool to ridicule others who were ignorant, vain or hypocritical, but advocated moderation instead of censorship (Aristotle, 1955). Henri Bergson (1911) also agreed that laughter was meant to humiliate and consequently correct our neighbors, although he attributed all humor to the encrustation of machine-like qualities and living beings. Thomas Hobbes (1968) wrote the following oft-quoted passage:
Men laugh at the mischances and indecencies, wherein there lies not wit or jest at all . . . Also men laugh at the infirmities of others . . . I may therefore conclude that the passion of laughter is nothing else but sudden glory arising from some sudden conception of some eminence in ourselves, by comparison with the infirmity of others, or with our own formerly.
Humor scholars and practitioners, who have devoted their lives to humor, are understandably reluctant to characterize it in such a negative way. Many of them downplay the necessity to consider superiority as an essential element of humor. In fact, Abraham Maslow argued that this theory only applied to those at lower levels of development. He predicted that self- actualizers would have a more refined sense of humor, and specifically a distaste for sexual jokes. However, Robert Priest found that everyone, including the self-actualizers, preferred sexual humor as long as it was targeted at the opposite gender (Priest & Wilhelm, 1974).

Lawrence La Fave has repeatedly found that people prefer humor that is at the expense of an out- group (e.g., La Fave, Haddad, & Marshall, 1974). Dolf Zillmann and Jennings Bryant (1980) found that hot tea spilled on an experimenter seemed funny when the experimenter had been rude. Howard Pollio found that two-thirds of all humorous remarks in groups were directed at some specific person or situation, and that the majority of these remarks were disparaging (Scogin & Pollio, 1980). Charles Gruner claims to be able to explain any joke or form of humor from a superiority perspective (Gruner, 1997).

Some argue that, for children at least, laughter may be a "roar of triumph" on solving a puzzle or mastering the cognitive challenge of a joke (Harter, 1971; McGhee, 1974; Zigler, Levine, & Gould, 1967). At least it is clear that people do not usually laugh (except in a nervous way) at situations or people that frighten them. In this sense they laugh only at things over which they feel a certain superiority.

Perhaps superiority theory explains the beneficial effects of humor on health, both physical and psychological. Laughing at a problem, according to superiority theory, signifies an ability to rise above it. Anything we can laugh at is not overwhelming to us. Thus, when we laugh at our problems, they seem somehow smaller and less threatening. Then we can get on with our healing, without the fear and panic normally associated with "disease."

Cognitive theories represent a different approach to explaining when people will be amused and generate amused laughter. These theories look at the humor from the "response side" of how we react to humor stimuli, rather than analyzing the humor stimuli themselves. According to Daniel Berlyne (1969) laughter is the result of either high arousal beyond our normal tolerance, or a brief arousal followed by a sudden "jag" when the arousal turns out to have been unnecessary. These theories map well onto incongruity and incongruity-resolution theories respectively, seeming to describe our response to those stimuli.

Robert Latta goes further to say that incongruity is irrelevant to the humor process (Latta, 1998). He feels that it is our response (regardless of the stimulus) that defines humor. He claims that nothing we can resolve was really incongruous anyway, and asserts that laughter merely serves to actively "re-set" the body to its former relaxed state after a state of "unrelaxation." This state of unrelaxation sounds a lot like Berlyne's arousal, but is defined so broadly that one wonders if we are ever relaxed under that definition. Cognitive theories are speculative at the moment, but are well suited to the sort of fMRI testing that is now becoming prevalent in brain research (e.g., Gallagher et al., 2000; McCrone, 2000; Ozawa et al., 2000). Of course, it is not clear whether these investigations will challenge other accounts of humor or simply serve to explain how they operate.

Integrating the Theories

Although the advocates of various theories debate one another with considerable acrimony, it seems to this author at least that the existing theories of humor can be integrated in the following way" (a) incongruity of some sort is required to get the attention of receivers (perk up their ears). Congruous events are commonplace. This aspect of the integration acknowledges the contribution of incongruity theories; (b) if that incongruity is not seen as threatening or frightening, it can be characterized as amusing. This aspect of the integration acknowledges the contribution of superiority theories; (c) depending on the degree to which this incongruity taps into normally-repressed areas such as sex or aggression, it will be more or less funny (up to the point of offense). This aspect of the integration acknowledges the contribution of relief theories. The integration is illustrated in Figure 5.


To review this discussion, humor means the enjoyment of incongruity (Morreall, 1989). The phenomenon of humor requires the participation of at least two parties: an object (probably incongruous) and an appreciator (probably feeling superior). It also usually involves an initiator and often some sort of onlookers. The context within which humor occurs is complex and interacts with the humor itself. There are many "theories" of humor. Some are theories about the function of humor (predominantly to vent or conserve psychic energy), some are stimulus theories (predominantly incongruity theories, with or without resolution), and some are response theories (experiencing a pleasant cognitive shift and/or a feeling of mastery).

Jim Lyttle, Ph.D.
© 2003