Theory of Humor as an IFF
The evolution of humor, its origins and biological function. Theory of humor as an IFF. (An IFF is an Identification, Friend or Foe system, a system used during group combat situations to probe group allegiance and ascertain which individuals should be treated as friend or as foe.)
It is suggested that human humor can most characteristically be treated as an IFF and the properties of military IFFs are compared with those of humor. As a test of the IFF theory of humor, it is used to interpret anthropological data about joking relationships in patrilineal societies. It is also argued that, in humans, humor and laughter together, have become a means of synchronizing group learning and forming social groups. They are, therefore, products of group selection.
Theory of Humor as an IFF - Humor, its Biological Origin, and Function
Summary of Argument for Theory of Humor
1 Introduction and General Comments
2 Bioepistemic Evolution of Humor
3 Incongruity and Relevance
4 From Sensory to Social Knowledge
5 Smiling and Laughter
6 Adaptation and Evolution of Humor
7 Aerial Combat and the Role of an IFF
8 Function of Humor in Humans
9 Biological IFFs and the Evolution of Humor
10 Properties of Humor and the IFF Theory of Humor
11 Humor, Aggression and Social Status
12 Testing the IFF Theory of Humor with Joking Relationships
13 Summary of IFF Theory of Humor and Conclusions
References
Summary
of the Argument to be Presented
Salient points in the development are :-
1. That "incongruities" in an input sensory data flow can be used to identify
parts in that data flow that are "relevant" to to the individual animal
that is the receiver for that data flow.
2. The ability to detect relevance is a fitness enhancing skill and most animals have developed the ability to detect input data that is incongruous with their existing understanding. This ability is manifested by such phenomena as the visual movement detectors found in almost all species. The necessary features of an incongruity detector are discussed and summarized as the I/R (Interpretation/Representation) model of learning and humor.
3. That advanced animals, especially while young, have come to enjoy incongruities. This enjoyment of incongruity will cause the young animal to focus on aspects of its surroundings that it does not presently understand and so help it to learn about its environment. Hence, young mammals enjoy play.
4. In humans cognitive incongruity detection has become linked to laughter so that children laugh while playing. Such laughter is a submissive gesture which aids in social learning by ensuring transmission of knowledge down a social hierarchy and helps to synchronize group learning.
5. The coding properties of the joke/laughter interchange are found to be analogous to those of the IFF systems used on aircraft (IFF = Identification Friend or Foe). Hence humor appears to be an IFF system for humans in which a joke corresponds with the interrogation role of the aircraft IFF while laughter corresponds to its transducer response.
6. In bioepistemic evolution, all evolving systems are bounded - that is, all evolving creatures or cultural groups are, in some way, separated from competing evolving systems. This IFF interpretation sees humor functioning as a social boundary forming mechanism; humor is preceived as interrogating the membership of social groups and, in so doing, setting boundaries around them.
7. Further evidence for the IFF role of humor in real human societies is presented from the distribution of joking relationships formed by adolescent males in patrilineal societies.
8. The IFF interpretation of humor is an essentially group selective interpretation and supports the argument that humans have evolved as a group selected species. This viewpoint, that humans are a group seelcted species, presently seems to be unfashionable.
1
Introduction and General Comments
When Charles Darwin wrote The Origin of Species he laid the foundations for a growth in biological knowledge that has continued ever since. Almost all aspects of the human animal are clearer when seen in the light that modern biology sheds upon it. However, humor, despite its ubiquity and importance, is an exception.
Studies of humor as a phenomenon date back to Darwin himself, who devotes considerable space to it in The Expression of the Emotions in Man and Animals (Darwin 1872). Remarkably, his work on humor remains read and relevant to this day. The subsequent years of debate, discussion and investigation by biologists, psychologists and psychiatrists, have not seen humor succumb to scientific investigation.
There have been many discussions (see, for example, Vaid 1999; McGhee and Goldstein 1983; Alexander 1986; Weisfeld 1993; Chafe 1987; Caron 2002; Jung 2003) but, despite these worthy efforts, no published theory seems adequate. In substance, humor remains a puzzle; we do not know where it comes from or what biological purpose it serves. Humor remains a phenomenon that stands alone with no obvious place in the scientific understanding of our species. The extent of its isolation can be gauged from the fact that many of today's large, university, psychology texts contain no mention of humor or laughter. Even works specializing in cognitive psychology fail to mention it - remarkable given that many theories for the origins of humor, including that to be presented here, suggest that it arises from the process of learning. In fact, humor probably does arise as some kind of cognitive mechanism, for evidence of which note the widespread use of humor in educational materials and educational broadcasting.
There are two reasons for this absence of humor from the, scientific view of humanity. The first is that science is a "serious" activity and seriousness tends to conflict with humor, making the design of experimental protocols difficult. The second reason is the lack of any grand theory that brings humor into the general framework of evolutionary biology - neither of Darwin's selective mechanisms, natural selection and sexual selection, lead to humor as an obvious consequence. The result is that, in essence, scientists have simply lacked experimental or theoretical handles with which to grasp many of the problems humor presents.
However, this author recently published his book The Architecture of Thought which introduced bioepistemic evolution, a generalized form of the evolutionary theory usually presented. Developed this way, evolutionary theory does suggest an origin for humor, or at least an origin for our attraction to incongruity and a basis for further theorizing. This article will not give a full description of bioepistemic evolution, just enough to present the arguments about humor, and it will use conventional terminology wherever possible. Thus this paper will try to be self-contained but readers should understand that the theory presented here is part of a larger development in evolutionary theory.
2
Bioepistemic Evolution
Bioepistemic evolution does not regard genes as fundamental to evolutionary theory. The three things it treats as fundamental are data, information and knowledge. Within one generation of any evolving system, data is interpreted into information which is selected from to produce knowledge. Human data comes from four sources, data from DNA (genetic data), data from sense organs (sensory data), data from social learning (cultural data) and data from subcultural or ethical knowledge, the last three of which are stored or processed in the brain. In one life cycle of a human generation, data from each of these sources is interpreted into information which is selected from to produce knowledge.
In this framework, genes may be seen as holders for the data involved in biological evolution or as a formatting of the genetic data on DNA. Genetic data is interpreted into proteins and cells, which are subject to natural and sexual selection, as described by Darwin. These selection processes then select the genetic knowledge that will be passed on to the next generation. However, bioepistemic evolution also recognizes those three other sources of data besides DNA.
2.1 Sensory Data
Large amounts of sensory data are harvested through the senses and the brain must select interpretations from parts of this data for closer attention. Incongruity, or incompatibility with existing perception, is a major criterion in this selection because such incongruity is a marker of the relevance of input sensory data. For example, as visual data is being processed into images, any moving objects in the image create incongruities between successive frames in the visual field. The brain selects those incongruities and focuses attention onto them. These are visual movement detectors but we have a similar ability to detect changes in sound patterns, odor, touch or taste; all our senses seem to have the ability to pick up such incongruities with existing perception. The ability to detect such changes enables us to detect and follow changes in our environment. Thus, sensory data is subject to incongruity selection. In general, sensory data is transmitted from sense organs to the brain, where it is interpreted into sensory information. The brain then applies some type of incongruity selection to select sensory knowledge from this sensory information.
As these modes of interpretation and selection have improved, the brain has become a Darwinian machine - a machine that mimics evolution as a process but works much faster. (This idea, that a form of evolution occurs in the brain, began with the American scientist Gerald Edelman and is now widely accepted. The argument is reviewed in (Plotkin 1994) and implies that the brain produces knowledge that will never enter genes.) Sensory knowledge accumulates by interpretation and selection occurring in one brain and dies with the organism possessing it.
As previously mentioned, one modality by which the brain selects sensory knowledge is incongruity selection. This form of selection manifests in such phenomena as visual movement detectors, which detect incongruities between successive visual fields, or the brain's ability to detect changes in background noise patterns. In young animals, incongruity selection seems to be implemented by causing animals to "enjoy," and therefore focus on, those aspects of their environment they do not presently "understand." In this way, incongruity selection became established in many species and also became the starting point for the evolutionary adaptations that produced humor in humans.
2.2 Social Knowledge and Evolution
Sensory knowledge is interpreted and selected entirely in one brain attached to one or more sense organs. However, some aspects of learned knowledge can be transmitted from one animal to another to produce social knowledge. Bioepistemic evolution distinguishes sensory knowledge from social knowledge from whether or not the selection process is confined to the receiving brain.
This one animal can learn from another animal by mimicry - merely copying the actions of another individual. Birds, for example, are very prone to mimicry but in mimicry only the learner selects the actions to copy. Mimicry is an inefficient way of transmitting relevant knowledge because the selection is performed by the initially ignorant learner. It is more efficient for the initially knowledgeable transmitter to select the knowledge to be transmitted. This is rare in birds but common in mammals - maternal teaching of the young being the obvious example.
To repeat - the inheritance of deliberately transmitted knowledge is different from inheritance by mimicry in that the selection of the knowledge to be transmitted occurs in the transmitting brain and is thus separated from the receiving brain in which the knowledge is accumulating. In mimicry it is the initially ignorant receiver who selects a behavior to copy; with deliberate transmission, it is the initially knowledgeable transmitter who selects the knowledge to be taught. Bioepistemic evolution uses this shift in the point of selection to distinguish sensory knowledge from social knowledge. So, selection of knowledge by transmitters gives rise to social knowledge or to culture. (Note that, in this respect, bioepistemic evolution differs from conventional theory, which does view knowledge transmitted by mimicry as cultural.)
Animals select information to transmit with one of two related motives. They may want to educate their young, e.g., by teaching them hunting and feeding techniques, or they may want to control the actions of other animals. In social animals, a desire for control will most often mean a desire to control the actions of other group members - that is, to exercise social power.
Hence, social knowledge accumulates to serve two underlying purpose, those being Educational and Political. The education of young consists of adults teaching group norms to their offspring. Human children are born with an instinctive desire to learn such norms, a fact clearly demonstrated by the language instinct, the drive children have to learn language (Pinker 1994). The attachment of incongruity to speech is a common feature of language learning - "What's this? It's a heffalump." More developed incongruities, in more obviously humorous forms, are a major force in adult group formation. Both phenomena indicate that the incongruity-based learning involved in the acquisition of sensory knowledge has become adapted to the needs of social knowledge and that, in humans, that adaptation manifests as humor.
2.3 Group Selection and Individual Selection
This subsection briefly describes the bioepistemic approach to individual and group selection. Where this paper uses the terms individual selection and group selection, the meaning attributed to them should be that described here.
In biological evolution, an individual's fitness is measured by reproductive success, which is determined partly by the data it inherits from its ancestors and partly by the environment it experiences during its life. This means that a solitary individual possesses two knowledge sets, one inherited in DNA and one that is derived from processing sensory data into knowledge and which describes its response to experience. A solitary animal's biological fitness depends upon these two knowledge sets, genetic knowledge and sensory knowledge, both of which are attached to it as an individual and both of which, therefore, give rise to individual selection.
Social animals have both genetic and sensory knowledge sets but they also inherit another set from their group, social knowledge or culture. Cultural knowledge is not specific to an individual, its is held in common by the group and is distributed around the group; it will, therefore, give rise to group selection. For a group selected species, an individual's fitness will depend not just upon his or her own biological success but also upon the traits and fitness of his or her group. One of the great advantages of cultural evolution is that cultural knowledge evolves much more rapidly than does genetic knowledge. As a result, species that possess bodies of cultural knowledge can adapt to changes in their environment more readily that can those who inherit only genetic knowledge. Thus social species can have two units of selection, the individual or the group and the question arises as to which of the two inherited knowledge sets, genetic and cultural knowledge, is the primary determinant of fitness. These two situations produce different units of selection, the individual and the group and, at a simple level, one might say that, a species in which social knowledge is the primary determinant of fitness is a group selected species, while one in which fitness is primarily determined by genetic knowledge is an individually selected species.
Put thus, the situation seems quite simple but there is a complicating issue, an issue that bears directly upon the subject of this paper. One finds that, when a knowledge set is being expressed to produce an evolving system - that is to produce an organism or a culture - the evolving system always produces some kind of bounding mechanism whose job it is to prevent invasion by competing evolving systems. For example, the bounding mechanisms of a human being include skin and the immune system - both play a role in preventing elements of non-self intruding upon its growth and development. The bounding mechanisms of cultural evolution are less obvious but, for a great many species, they involve scent and territory marking or direct recognition of individuals by other members of their group.
However, an animal's scent and physical appearance are both controlled by genetic data. Thus, for most social species, although the data that encodes social knowledge is specific to the group, the mechanisms that bound the expression of this social knowledge into a culture still utilizes data that is coded at a genetic level. In these circumstances, and for most species, it is ambiguous whether one can view cultural evolution as an indicator of group selection or as an indicator of individual selection. Thus, in terms of bioepistemic evolution, group selection can be unambiguously attributed only if :-
1. The evolving knowledge set is encoded as socially inherited data and
2. Second, the culture it produces is delimited using socially inherited data.
In general, all bounding mechanisms are IFF systems. For example, the immune system recognizes self (friend) and non-self (foe) by immunogenicity, while skin simply encloses self and forms a barrier against non-self. This is not the place to give an extended discussion of known biological IFF systems. However, it should be recognized that the present proposal that humor is an IFF would make it unique amongst biological IFF systems in that humor would identify friend or foe on the basis of socially inherited data.
Thus, this proposal is tantamount to suggesting that, more than any other organism, humans are a group selected species and that humor is intimately associated with social groups and their definition. It also suggests that the evolution of humor would have been a key step in the evolution the human species, it would have been a step that freed human cultural evolution from the genetic constraints that limit it in other species.
2.4 Ethical Knowledge
Bioepistemic evolution identifies a fourth form of knowledge, which is the subcultural or professional knowledge that distinguishes a subculture from a greater culture. The evolution that produces such knowledge arises in the structuration of societies when systems of rules or codes of ethics are either agreed between partners or mandated by social authority. When the parties to a dialogue follow such a code, it is the code itself, rather than either the transmitter or the receiver, that selects knowledge from the available interpretations. Hence another shift in the point of selection has occurred that renders subcultural knowledge distinct from cultural knowledge. In the parlance of bioepistemic evolution, it is level4 knowledge.
Subcultural evolution produces knowledge that is validated by reference to an ethical code, so an important example of level4 knowledge is professionally validated knowledge. The various professions are subcultures that develop their own sets of validated knowledge.
Humor plays no direct, general role in professional knowledge formation but, nonetheless, it will be useful to briefly consider science as a familiar example of ethical knowledge formation. This will both illustrate the point bring out the importance of incongruity in selecting valid knowledge from the various possible interpretations of an input data stream.
In western cultures, the community of scientists is a subculture made up of scientists doing science. This subculture has an input data stream drawn from experiment and observation. Any one section of the data stream may be subject to various interpretations, each of which is a hypothesis. An ethical code of science is Popper's logic, which demands that the selected hypothesis will be that which makes predictions that are not incongruous with the input data.
The question now is, how can science identify those parts of an input observational data stream that are most important or relevant? Popper's logic of science effectively asserts that, to improve the overall validity of scientific theory, science should concentrate on those parts of its input data stream that are, in fact, incongruous with the corpus of existing theory. In other words, to improve the corpus of scientific theory, Popper's logic suggests that scientists should concentrate their theoretical efforts on those areas where the data from observations must be interpreted in ways that are incongruous with existing theory. In sum, that the most relevant parts of the input, scientific data stream are those that are incongruous with existing theory.
Any organism with sense organs has a continuous stream of input data and a similar problem to the one described above. The input data must be interpreted and the most relevant interpetations identified. This paper argues that most creatures have found a solution very similar to that found by Popper for science, namely that they respond to incongruities because of the need to attribute relevance to different sections of the data flow from their sense organs.
3
Incongruity and Relevance
Any organism with sense organs receives a continuous stream of input data. The sense organ, which might be an eye, passes this stream of data to the brain which interprets this data into an "image" of its surroundings. This image is a model, a representation, of the world outside that is stored in some kind of temporary intellectual memory - in RAM, if one wishes to use computer parlance.
No matter how advanced that brain might be, it rapidly becomes overloaded by this copious data stream and has a problem; the brain must select those interpretations that seem relevant to its life and discard those parts that seem unimportant. Moreover, the eye is looking at the world through reflected light and few of the objects it sees will choose to reflect light or do anything to control the way light is reflected. The whole burden of interpreting this data flowing into the brain and selecting important interpretations falls onto the receiving brain.
So, the input data stream must be interpreted on the fly and relevant parts of that interpretation selected for closer examination. In these circumstances the question is, "What general criterion can a data receiver use to select for relevance?" One answer, and the answer that is emphasized by the present work, is that the most relevant interpretations are those that are incompatible with, which can be rephrased to incongruous with, the brain's pre-existing representation of the world. This is the starting point for the present interpretation of the origins of humor.
An animal's visual data stream is used to create a model, a representation of the world. Provided all the objects in the external world remain still, the animal's representation of it remains constant. If an external object begins to move, the corresponding region of the animal's representation will develop incongruities when comparing one visual frame with the next. Whether the animal is prey or predator, these incongruities mark those parts of its visual field that are most relevant and on which the animal needs to focus its attention. In other words, an animal can recognize some regions of relevance from its input sensory data stream by selecting those parts that are interpretationally incongruous with its existing understanding.
(Added Note. The paper by L. Itti and P. Baldi (2006) seems very relevant. The "Bayesian Surprise" mechanism they describe is very similar to the incongruity selection I discuss above. Although their work comes from a quite different frame of reference and they do not discuss humor, their arguments nonetheless seem to support this selective mechanism.
L. Itti and P. Baldi (2006) Bayesian Surprise Attracts Human Attention, In: Advances in Neural Information Processing Systems, Vol. 19 (NIPS*2005), pp. 1-8, Cambridge, MA:MIT Press, 2006)
3.1 Minimum Features of an Incongruity Selector
Incongruity selection has implications for how sense organs and the brain work together. In particular, an incongruity cannot be detected unless an existing representation is stored in such a way that it can be compared with ongoing interpretations. The must exist a stored representation that is separate from, but in communication with and comparable with, ongoing interpretations.
For example, data coming from the eye must be interpreted and the resulting interpretation compared with the preexisting representation. When incongruities between the stored representation and the ongoing interpretation are detected they need to become the target for additional attention and the results used to update existing stored representations. A device that is capable of this processing will need certain minimum features, which may be described by the following picture.
Visual data must be passed first to an interpreter that converts the data stream into a stream of interpretations. This device is omitted from the diagram but it passes its interpretations to a region that will be called the I-module. The I-module is a short term storage device that maintains a mapping of these on-the-fly interpretations for the fraction of a second needed to produce the next interpretation.
The I-module is connected to an R-module, which is a longer term memory storage area where ongoing representations are maintained. These may, or may not, be separate areas of the brain but, since they need to hold and compare separate descriptions of the world, it is likely that corresponding regions of each will be connected in parallel. The R-module also receives an input from a desire, or self-interest module that provides political direction and an indication of how this organism would like the world to be. The self-interest module is a long term region of storage where the self-interest and desires of an individual are maintained.
The I-module and R-module communicate with one another and so provide inputs to one another. The I-module also has input from the data interpreter and the R-module from the self-interest module. Therefore, both I-module and R-module have two inputs and the two inputs can contradict one another, be incongruous with one another, in either module and at discrete points on their mapping.
The I/R model is undoubtedly a very simplified picture of animal learning but it has several characteristics that make it useful for an understanding of humor. It does depend upon incongruity, which is a pivotal and little understood aspect of humor in humans. It also indicates that some incongruities should induce distress while others should induce pleasure, an apparent contradiction which is found in humor but whose origin has not been altogether clear. The I/R model does not describe human humor in all its complexity but it does offer a foundation from which such descriptions might be developed.
3.2 Note on I/R model and neural networks
From the point of view of artificial intelligence simulations, the I/R model implies that incongruity detection might be seen as switching between the "use" mode and the "self-training" or "learning" modes characteristic of neural networks.
On this basis, the detection of incongruities in the I-module or R-module might be used to switch between "normal use," "pleasure/learning" and "distress/learning" modes in the brain. However, it is unclear how many other modes, or switches between them, real brains may possess. (I am indebted to my son for these insights.)
4
From Sensory to Social Knowledge
Humans, like other animals, have motion detectors that focus our attention on moving objects, implying that the human brain makes use of incongruity selection to assist in learning about its environment. Also, like other animals, we are curious especially as children and want to understand everything and minutely examine everything we do not currently understand. To this end, we watch people at work and mimic the things they do.
Such learning mechanisms help individuals but they do not amount to the uniquely human sense of humor. Humor is not an individual trait, it is a social, group-directed phenomenon and its evolutionary pathway must be traced through the further adaptation of those individual learning mechanisms to fill social roles. Knowing the evolutionary origins or neurobiological mechanisms of incongruity selection in an individual tells us little about the social role of humor or the adaptive benefits it offers in group situations.
To gain insights into the social aspects of humor it is necessary to examine social structures and make a point that concerns the holistic properties of evolution. Holistic arguments in evolution have a checkered history, so this argument might best be developed by analogy with a human organ - the hand will be chosen, though any other organ could serve.
The hand is made from skin, bone, tendons, muscle, nerves and nails etc. Each of these tissues has its own, individual role in the hand's function and each will have its own, separate evolutionary and developmental history. Human adaptation has merged their roles to create a whole, integrated function in the hand. Evolution has holistically assembled these tissues around the performance of such roles as gripping and holding etc. Each of the hand's component tissues cooperates to enable these roles to be performed.
This is how things are likely to be with humor. As time has passed, evolution has assembled the components of humor from various starting points and caused their products to cooperate to produce an integrated "organ" of humor that functions at a social level. Humor is an identifiable, integrated feature in human social behavior. Whatever the evolutionary origins of its component parts or its neurobiological mechanisms, humor cannot be comprehended merely in terms of its parts or mechanisms. Humor must also be understood in terms of the functions it performs in social evolution, that is, the functions its components cooperate to perform once they are assembled into the integrated whole that is humor. Further analogies could be drawn here with the way genes cooperate to produce protein molecules, with the way different protein molecules cooperate to produce cells or with the way, in multicellular species, differently developed cells cooperate to produce an organism. These are the kinds of things that, it is argued, arise by holistic assembly through the processes of evolution.
As animals form social groups, they become subject to group selection; that is, their own success or failure begins to depend upon that of the group of which they are a part and they begin to cooperate with one another to ensure its success. Then their brains, the locus of sensory knowledge selection, must change to create concern for the group as well as for self. Individuals are selected both for their ability to act as the nuclear leader around whom a group can form and also their ability to achieve and maintain subordinate membership of such a group.
Under this selection pressure, social groups are assembled from solitary, individual animals. As group formation proceeds, the self-directed intellectual processes that characterize the brains of solitary animals are adapted to serve the needs of social knowledge. These group directed processes must encourage social animals to do for their group's legacy of social knowledge what all organisms do for their genetic inheritance - protect and propagate it. As a social phenomenon, humor must help to do this. Here are some of the functional roles it is suggested that humor plays in social knowledge:-
. Provides a physiological pleasure reward to individuals who unite into a group defined by the same social knowledge.
. Protects social knowledge by enabling its possessors to identify those who do not share it. In other words, function as an IFF cued by social knowledge.
. Incongruity serves as an aid to individual learning in all species but, taken together, humor and laughter help to synchronize a human group's social knowledge and aids in attacking those who do not share it.
. Perpetuates social knowledge by encouraging its transmission down the generations.
It is argued that humor does all these things but that the least recognized and, in many ways, most distinguishing aspect of its social function seems to be as an IFF. The IFF role will be the main focus of this paper but, first, some physiological aspects of humor must be considered.
5
Smiling and Laughter
Humor is recognizable by the state of being amused which is identifiable by two responses, laughter and smiling - laughter being the more characteristic of the two and largely confined to humans. Without laughter, humor may not be distinguishable from simple enjoyment. Nonetheless, humor is neither necessary nor sufficient for laughter. Humorous situations do not necessarily produce laughter - and laughter may occur in non-humorous situations. Smiling and laughter are communicative acts, both of which are, in different ways, gestures of submission.
5.1 Smiling
Smiling is a common act. People smile so often they develop wrinkles on their faces because of it - for example, the 'smile lines' around the eyes. Smiles are silent, transient, directed signals - characteristics that make them narrowcast rather than broadcast messages. We smile at someone, or to a group, rather than at everyone. Thus, fundamentally, smiles are acts of one to one or one to small group communication.
A smile involves a drawing back of the gums to expose the teeth. A similar gesture is a common act of submission among primates and might be directed to an -male. This is why smiling seems an act of submission, a fact that explains why we like to be smiled at - we are, essentially, being submitted to.
When people smile at one another, smile mutually, they are, effectively, submitting to one another, a mutual submission that may be thought of as submission to the group 'we' of which both are a part. Mutual smiling is, therefore, a group directed behavior, an act that recognizes the person to whom the smile is directed as a fellow group member and, sometimes, recognizes their hierarchical status.
The act of smiling is largely voluntary - all the necessary facial changes can be made on command by actors or workers who are instructed to do so, such as airline hostesses or supermarket checkout assistants. Nonetheless, some aspects of smiling are very subtle and difficult to perform at will, allowing observers to sense the differences between false and natural smiles. Hence it is difficult, though not impossible, to produce convincing, natural smiles on demand.
5.2 Laughter
Laughter is largely confined to humans, though some higher apes exhibit similar responses. Laughter largely concerns humans but a classic, comparative study of laughter among primates is (Van Hooff 1972).
Observers differ as to whether smiling and laughter are distinct, or whether they should be seen as falling onto some single continuum of amusement. This author's view is that smiling and laughter are structurally different and should not be seen as falling onto a single continuum. Laughter is so different from smiling that it actually bears striking similarities to crying - a very ancient gesture present in many species. Both laughter and crying are involuntary, both involve rapid exhalations of air that produce recognizable sounds, both can involve tears, though tears are more normal in crying, and both are induced by incongruous experiences or observations. Crying is induced by events that are incongruous with desire or self-interest or even by events that seem threatening. By contrast, laughter is induced by events that are incongruous with existing perception but which seem to pose no threat.
Unlike smiling, laughter produces a sound and is involuntary. Hence laughter acts as a broadcast signal and its involuntary nature suggests that the information it broadcasts is of a type that must be transmitted. This fact, that laughter is an involuntary reaction producing a broadcast signal is analogous with the squawk response of aircraft transponders, and is one of the main reasons for identifying humor as an IFF.
6
The Adaptive Significance of Humor
Before discussing humor as an IFF, earlier suggestions for its functions need to be considered. (Vaid 1999) and (Jung 2003) review these.
Vaid gave three categories but for our present purposes her 'psychological' and 'metaphysical' categories can be laid aside and the remainder reordered under headings designed to fit this work, those headings being :-
The origins of attraction to incongruity.
The adaptive benefits to the individual.
The adaptive benefits to the group.
6.1 Origins of attraction to incongruity
There seem to be few suggestions as to why incongruity with existing ideas is attractive, rather than some other feature of a data stream. So far as the author knows, the suggestion that incongruity can be used as an indicator of relevance to trigger a learning mechanism seems to be original and is the only proposal in this area.
6.2 Adaptive benefits to the individual
Humor is, beyond doubt, an essentially social phenomenon and most theories about humor recognize its social role. However, humor could not have evolved if its component parts played only social roles. The traits from which humor evolved must already have been common in the population, and therefore providing adaptive benefits to individuals, when the first social benefits began to emerge. Were things otherwise, were these traits not beneficial to individuals, the first humorous mutants would have enjoyed no selective advantage over their humorless peers and humor producing genes would not have propagated within the population.
The proposal that attraction to incongruity is part of a learning mechanism, arising from the need to ascribe relevance to different parts of a data flow, automatically provides an individual benefit that would make attraction to incongruity common.
Other suggestions have been offered. Arthur Koestler discussed humor in The Act of Creation (Koestler 1964) and suggested that humor achieved a 'bisociation' of ideas that enabled the creation of new ideas by forming links and associations between existing but disparate concepts. It is true that the ability to develop new ideas this way might give an adaptive advantage to individuals. However, the meaning of the term 'bisociation' is not altogether clear, neither is it obvious why and where, in evolutionary history, this capability might have arisen.
It has been suggested (Chafe 1987) that laughter arose to disable individuals and prevent them pursuing unwise avenues. This suggestion seems unworkable. It is not obvious that disablement could be an evolutionary advantage in any circumstances. Moreover, the idea implies that one function of the brain is 'wise' and gifted with the foresight needed to detect 'unwise' policies conceived elsewhere in the same brain. It is hard to see how this organ of wisdom would work or arise and especially hard to see why it would be unable to intervene except by disabling the entire animal. It is also unclear why this faculty, if it exists, might be confined to higher primates.
6.3 Social adaptations of humor
It seems clear that, in humans, humor plays its major roles at a social level and most suggestions about its adaptive value reflect this expectation.
Weisfeld (Weisfeld 1993) suggests that humor supplies a social stimulation that motivates us to obtain fitness-enhancing inputs in the social, sexual or aggressive domains.
Alexander (Alexander 1986) writes supporting the case that humans are a group selected species and suggests that humor is a means of status manipulation, at times a means of excluding certain parties from a group and, at other times, of reinforcing the group's cohesiveness by showing that they all share the same joke. Alexander's work seems very consistent with the picture presented here.
Dunbar (Dunbar 1996), in a work on the evolution of language, suggests that humor arose during intimacies such as grooming, gossip etc.
All these suggestions for the social role of humor seem highly plausible and likely to contain large elements of validity - indeed, they seem to formulate and develop our understanding of phenomena that are commonplace aspects of human experience. Each of them seems to contain large elements of truth but the very fact that each seems to be unarguably true also indicates that no one of them can be a complete analysis.
One cannot reject any of them and so, to go beyond them, they must be unified and integrated into a single, larger picture. That picture needs to identify the greater social structures of which humor forms a part and the general role humor plays in those greater structures. In some respects, the suggestion in (Jung 2003), that humor creates the involuntary response of laughter that allows us to "mindread" the mental states of other people and determine "cooperator value" is moving toward the kind of theory discussed here.
7
Aerial Combat and the Role of an IFF
Humor's social roles indicate that it has been shaped during the social phases of human evolution and thus by competition between human groups. In the circumstances it will help to consider the nature of group competition and group combat, which can be done most easily by analogy with a modern example, namely aerial warfare.
Modern warplanes do not fight as individuals but as groups and, as they are doing so, they communicate extensively with one another. These aircraft have weapons systems, to attack their enemies, radar sensors with which to scan the field of combat for targets and radio communications systems through which to exchange information with allied planes.
Just as important, and linked to weapons, sensors and communications, modern planes have IFF (Identification Friend or Foe) systems. An IFF would serve no purpose for a solitary combat aircraft but it is vital for planes that fight alongside allies. An IFF is an electronic device linked to a plane's radar system. It comprises two parts: first, an interrogator to send coded signals to targets identified on the radar; second, a transponder, that receives and decodes interrogation signals from friendly radars and broadcasts coded replies. (The author knows of no review of this topic in the biological literature but interested readers will find descriptions of some operational IFF systems in the radar section of any recent edition of Jane's Avionics.)
When a radar detects an unknown aircraft, the operator needs to know whether this blip is a friendly plane or an enemy. To find out, the radar's IFF interrogator transmits a coded signal to which a friendly aircraft's transponder replies with another code that will be read as "friend" and identify the specific aircraft. Failure to respond with a valid code leads to identification as "foe" and possibly to attack with a missile. Hence, it is very important that interrogated, friendly aircraft positively respond with the correct code and IFF transponders reply to interrogation signals automatically - pilots do not hear the interrogation signal or decide whether to reply.
There is a striking correspondence between the interrogator-transponder exchange between combat aircraft IFFs and the joke-laughter exchange between humans. This is summarized in the next two paragraphs with the points of correspondence emphasized.
An aircraft IFF uses an exchange of signals, with the interrogation signal requiring a code that is shared between the two aircraft, while the transponder response is an automatic, transient, broadcast radio signal.
The joke-laughter dialogue is an exchange that requires a body of knowledge shared by both joker and recipient, while the laughter response is an automatic, transient, broadcast audio signal.
This five point correspondence within such brief dialogues seem very unlikely to be coincidental and is a primary reason for suggesting that humor is an IFF. The name and initials IFF are a modern terminology to describe the electronic devices installed on military aircraft, ships and, increasingly, on military ground vehicles. However, these electronic devices are recent innovations - less sophisticated IFFs have been part of warfare for centuries and are used in all team games. The hails and passwords used by sentries are an IFF - the traditional cry being, "Halt, who goes there, friend or foe?" It is followed by a demand for the current password. Easily recognizable uniforms are an IFF that tells everyone on the battlefield the side on which a soldier fights (and his rank), as do the quickly identifiable colors worn by members of football teams etc. During world war II, the crosses and roundels carried by opposing aircraft were also an IFF system. In most of these cases, IFF devices signal their group allegiance automatically. Hence, an IFF seems essential for any group that hopes to emerge victorious from team 'games' and war is, for these purposes, a serious, team game.
On a military aircraft, the IFF can be thought of as sitting between sensors,
communications systems and weapons systems. The IFF uses shared codes to
decide the group allegiance of other aircraft and thus decides whether weapons,
or help, support and information, should be directed at them.
In computer terms, the IFF process may be seen as similar to the handshaking protocols computers go through as a preliminary to networking with one another. Recent combat aircraft are, in fact, equipped with very powerful computers and groups of combat planes do form computer networks. These may be peer to peer networks, if all planes have equal roles, or they may be client-server networks if one aircraft has a command and control role. (The American AWACS is an aircraft with such a command role.) Most planes seem to have hybrid capabilities and are able to take part in either type of network but the client-server architecture is notable because, like human groups, it contains a hierarchy. The server is at the top with client aircraft below. Other planes, those not identified as friend, are not really part of that network at all but, for some purposes, it may be useful to see non-friendly but neutral planes as lower still on the hierarchy, with enemy craft at the bottom.
In these networked, combat groups, the IFF decides the nature of communications with other planes. Aircraft identified as friend are joined to the network and allowed to upload sensor information about the battle zone, either directly or via the control aircraft. In return, the network 'teaches' its members about the battlefield, which means that the network synchronizes the way its members 'learn' about their world.
Aircraft that are not identified as friend, aircraft that fail to give a transponder response or which give an incorrect response will, at the least, not be drawn into this learning network. The attention of the combat group will be focused upon these incongruous aircraft. They will be assessed for any potential threat they may pose and labeled accordingly. Depending on that assessment and label, non-friendly aircraft may, or may not, be attacked and destroyed.
To summarize, the electronic IFF systems on aircraft began to be developed around the end of the second world war, in response to the number of allied aircraft destroyed by friendly fire. The IFF determines group membership and the targets for aggression but, as the development of these systems has proceeded, they have come to do something else which seems significant for understanding the nature of social knowledge and the educational process - the IFF has also come to synchronize the learning, the social knowledge, of the group whose membership it controls.
8
The Functions of Humor in Humans
It has been suggested that incongruity can be used as a marker to indicate the relevance of different sections of a data flow. Hence, it is argued, attraction to incongruity will improve the efficiency of sensory learning and such attractions exist in many animals.
Humans, it is argued, have passed through a period of selection that have given incongruity selection some uniquely human features. In humans, the incongruity-based learning mechanism has become adapted into humor, which plays social roles probably best indicated by the properties of laughter, the most obviously unique marker of the way humor has developed in humans.
It is suggested here that humor plays several social roles in human, social evolution. This section will mention three of them.
. Humor provides a source of pleasure and satisfaction that is unavailable except through group membership. This rewards group membership and thus enhances the transfer of social knowledge.
. Humor serves as an IFF, a way to distinguish friend from foe by their social knowledge set.
. In adults and children, humor serves to aid communication and individual learning and to synchronize group learning.
It is humor as an IFF that seems to best summarize its observed properties. All evolving systems must have some sort of boundary forming mechanism to separate or distinguishing self from non-self. In general, these boundary forming mechanisms are IFFs - some simple examples are barriers, like the walls or the membranes around cells. These identify "self," of friend, as inside the barrier while non-self, or foe, is identified as outside. Another well-known example of a biological IFF, found in higher vertebrates, is the immune system, which is a very sophisticated IFF. Social animals often use scent to determine whether or not another individual is a member of their group. Thus biological IFFs are known and it is here suggested that humor is a human IFF, one that serves to classify individual humans as "part of" or "not part of" a particular culture.
There are clear analogies between humor as an IFF and the military situation but that analogy cannot be followed too closely. The biological and military situations differ in several ways.
. Military IFFs did not evolve. Rather, they were designed by aircraft engineers and military planners. If humor fills an IFF role, it does so only insofar as evolution has adapted it to that role. Humor will have evolutionary forebears whose earlier roles may still be visible.
. Military planes do not fight for status in their own hierarchy and should not attack members of their own group. Humans do fight for status in their groups and fight other group members in order to get it. Hence humor, as a biological IFF, would be expected to look for targets within its own group, something a military IFF should never do.
. Finally, military aircraft are machines and simply do their job. Humans are not machines and need to be motivated.
The need for motivation is answered by the way humorous activities are a source of pleasure obtainable only within a community. This motivates people to form the social groups needed for social knowledge to grow.
8.1 Humor as aid to communication and individual learning
"Beware the jabberwock my son, the claws that scratch, the teeth that bite." This is a funny sentence. We know it is funny because many people find Alice in Wonderland funny so and their reaction is the only criterion.
Carroll's sentence is a communication, ostensibly from father to son. It is the word "jabberwock" that creates the humor and on which the reader's attention becomes focused. Replace "jabberwock" with "dog" and the sentence loses its humorous content, becoming neither funny nor interesting. One can imagine a teenager's response if his father so advised him to fear a dog, "Yes dad, I already know that dogs have claws and teeth that scratch and bite." But what is a jabberwock? "It is something to be feared because it has claws and teeth with which it scratches and bites and because dad says I should fear it. But what is a jabberwock?"
The focus on 'jabberwock' arises from incongruity selection. It is the nonsense word, the incongruity with existing understanding, that attracts attention and causes the reader to think.
The implication is that incongruity selection mechanism has become adapted to processing social knowledge. Incongruity selection can be a means of attributing relevance, and directing attention to, different sections of a sensory data flow, plays a similar role in social knowledge; it engages attention to a communications and says, in effect, "pay attention, because there is something in this sentence you do not understand."
And it does more; as a reward for paying attention and learning the new things this sentence contains, the incongruity selector engages the pleasure centers of the brain. Not only does the individual learn, he or she enjoys doing so. The pleasure causes the recipient to smile or laugh, subordinating gestures that please the transmitter and encourage the two to form a social pair.
For evidence of pleasure in learning, observe the behavior of young mammals as they play near their den but note that their's is an individual learning process, not a social adaptation. The enjoyment exhibited by children as they learn language and other social norms from their carers is a social learning process with group knowledge being transmitted. The social knowledge children learn makes them grow to be part of the group from which they learn it.
8.2 Humor and laughter as a way of synchronizing group learning
Social evolution is about communication but information alone does not induce pleasure in the recipient of a communication. The insertion of an incongruity into the message does. A submissive gesture by the recipient returns that pleasure and is a way of signifying that the recipient has learned the content of the message. Submission is also appropriate as a learned message will control and, in some way, change the behavior of the learner.
Smiling is an apt response to communication within a social pair because a smile is a narrowcast communication - one routinely smiles at one person but it is difficult to smile at a whole group. Sending a message of amused learning to a group requires a broadcast communication of submission and sound is the best method of broadcasting a communication around a human group. Human evolution seems to have achieved this broadcast communication by modifying that other ancient gesture of submission, the cry, to create laughter.
Children laugh incessantly while they are playing and their laughter sends signals to anyone within earshot. To any caring adults in the vicinity laughter says, "I'm OK; I'm happy and not worried." Generally speaking, the adult will not intervene.
The laughter says to other children in the group, "This is interesting. I get pleasure from it and from thinking about it. You too may get pleasure from it." So, other children come and investigate and learn from the same observation. In the end, each member of the group learns the same things and derives shared pleasure while doing so.
The net effect is a pattern of humor, attention and laughter that synchronizes group learning. Incongruity-based learning means that children who grow together laugh together and, even though they may be genetically unrelated, come to share the same social knowledge set. Humor and laughter drive and synchronize their group's learning.
The evolutionary point of this synchronization is that mankind is a social species. The group that grows together shares the same social knowledge and, as a result, its members become allies in competition with other groups possessed of different knowledge sets. And, in that competition, humor will help these groups to decide who are their friends and who their enemies.
9
Biological IFFs
Many social, group-selected animals have IFFs based on scent, each group developing its own characteristic odor. For example, badgers occupying the same set urinate on one another and come to share the same, rather pungent smell. Group members recognize one another by this smell and fights occur with badgers from other sets who intrude onto their territory but have a different smell. Canines likewise recognize pack members by their smell and, so it is said, the reason dogs dislike taking a bath is that they fear being attacked if other group members cannot recognize their smell. (The author is not aware of the term IFF being previously used for these behaviors.)
Odor works well as an IFF for intelligent animals living in small groups who have a keen sense of smell. It would work less for creatures that live in large groups and have a poor sense of smell but any IFF must have certain properties:-
1. It must send signals to interrogate the group allegiance of other individuals.
2. The signal must be group specific and coded, that is not something that can be easily replicated. Hence, intruders will neither respond positively, nor be able to elicit positive responses, from existing group members.
3. The responses should be automatic - individuals should be unable to control whether the positive response is transmitted. (A group specific odor is a signal but it is limited as a response. Canine tail-wagging may be the automatic, positive response used to signal that a doggie friend has been recognized.)
4. The response must be broadcast and detectable by all individuals in the vicinity.
Odor would not work well as an IFF for humans. We have a poor sense of smell and we live in large groups. We do not even have tails to wag. Nonetheless, like any other social species, our evolutionary games are played in teams.
We need an IFF for our cultural evolution and it will use one of our two most important senses - vision or hearing. Our communications use speech so it is most likely that a human IFF will use sound. Vision can play a role in IFF identification, because we can recognize close group members and our physical heterogeneity makes this recognition easier. However, visual recognition has weaknesses as an IFF because the data from which it keys its recognition is our appearance, which is genetically controlled. (See section 2.3). Some humor is visual and, in that form, keys its recognition from genetic knowledge, but most humor is based on verbal communication which keys from socially transmitted data. Thus humor can be a form of IFF whose operation is freed from genetically encoded knowledge, even though its neurobiological assembly of humor is genetically controlled.
10
Properties of Humor Suitable for an IFF
The most characteristic manifestation of humor is laughter and many of humor's aspects can be judged from laughter. The three important laughter inducers are tickling, childhood play and humorous communications, jokes being the most distinctive of the latter.
Tickling and ticklishness are thought linked to the grooming behavior seen in many primates. In primates, mutual grooming is strongly linked to group membership and hierarchy. Being permitted to groom is an identification as friend, while who grooms who, is linked to hierarchy. Grooming clearly induces pleasure, as do both humor and tickling in humans. Since both produce laughter in humans, humor and tickling presumably stimulate the same pleasure centers. Childhood play has already been discussed and the laughter it induces seems likely to be an early, broadcast reaction to pleasure from incongruity and a means of synchronizing group learning.
All these matters will now be laid aside to consider jokes as laughter inducers. All the following properties are familiar aspects of jokes and of our response to them.
. Jokes are communications. Only communicated jokes are funny. We do not laugh at our own jokes because they cannot be incongruous with our own knowledge set.
. Jokes are specific to a social knowledge set. This is clear from the way jokes such as puns and logical incongruities fail to translate from one language to another. Laughter is induced only in recipients who possess the requisite social knowledge set for the joke to be incongruous with. This untranslateability gives jokes the properties of coded signals that interrogate the group membership of receivers. To 'get' a joke you must share group knowledge with the joker.
. When we 'get' a joke we laugh audibly, thus broadcasting the fact that the responder and joker are in the same social group - have social knowledge in common.
. Laughter is involuntarily, or at least hard to control. In other words, we are automatically amused, we automatically broadcast the fact of our amusement, and thus of our group allegiance, to everyone within earshot.
Together, these properties of humor are those of an IFF that selects friend from foe according to social knowledge set. Laughter, the positive response to jokes, identifies the amused person as sharing the linked knowledge set and as friend to the joker. The negative response of failing to laugh identifies the unamused person as not sharing that knowledge set, not a group member and, therefore, as foe to the joker. Thus humor is, as Meyer (2000) puts it, a double edged sword, at once group forming and group excluding.
10.1 Comparison of IFFs and humor
It will be useful to summarize the general properties of military IFFs and humor side by side. This is done in Table 1.
| IFF | Humor | |
| Interrogation signal | Initial interrogation is coded to be readable only by friends | Jokes are "got" only within a shared social knowledge set or language. |
| Response signal | Positive response is coded | Positive response is not coded. |
| Positive response is broadcast. (Engineers might like a narrowcast response but that is not feasible.) | Positive response is broadcast as the sound of laughter. | |
| Positive response is automatic and identifies friend. | Response is automatic, to the extent that laughter is involuntary, and identifies friend. | |
| Negative response identifies non-friend. | Negative response identifies out-group. | |
| Linkage to weapons | IFF is linked to weapons systems. | Humor has aggressive modes. |
| Linkage to communications | Planes identified as friend take a place in the communications network and share information. | Individuals who share humor take a place in the group hierarchy, are informed and listened to. |
| Unidentified targets. | Planes identified as foe are excluded from the network and may be attacked. | Individuals who do not share humor are excluded from groups and may be mocked, sneered at or attacked. |
| Linkage to hierarchy | Planes in client server network "know their place," do not try to change it and do not attack friends. | Humans do not "know their place." Humor is strongly linked to the struggle for hierarchical status and thus to intra-group aggression. |
11
Humor, Aggression and Social Status
Humor has links with aggression - not surprising since an IFF's job is to identify targets for attack - and it is notable that many missile systems can automatically engage targets identified as foe.
Joking and laughter do demonstrate group membership and shared knowledge but human humor must do more than a military IFF; it must help in the struggle for position on a hierarchy. Human groups are headed by dominant -males (usually males) who exercise political control over the hierarchy below them. The -male's word is law and his controlling actions are very influential in establishing the group's social knowledge set. Hence, a group's communicative links resemble, but are more complex than, those of a client-server computer network, with the -male taking the role of controlling server. Much of human life involves the struggle for status on such hierarchies and aggression is often targeted within them.
Any human IFF, whether it be humor or some other property, will not merely identify members of other groups as targets but must also find targets in its own hierarchy against whom aggression can be directed.
Many forms of humor manifest this aggressive struggle for status. For example, a bully or group of bullies might comment about aspects of some quarry's person or personality. The victim does not laugh but the bullies find it funny and their laughter may recruit onlookers to join their efforts. The consequence may be a demotion of the target down the social group or even his or her expulsion from it. The victim may even be identified as a group foe and labeled as a legitimate target for physical attacks.
Aggressive humor is usually directed at subordinates or equals. Humor directed at social superiors can be risky and -males are not usually chosen as targets. Conversely, it is doubtful whether nominal superordinates who lack the power to retaliate for misdirected humor can retain any real superordinate status.
Hence, some aspects of humor are aggressive. When aggression is directed at out-groups, humor's role will be similar to that of a military IFF. However, as a biological IFF, humor must also find in-group targets as part of the struggle for group status. In directing aggression within the human group, humor will display properties that reflect the hierarchical nature of those groups but which will have no parallels in military IFFs.
12
Testing the IFF Theory of Humor with Joking Relationships
Scientific theories are advanced in order to be tested, possibly to destruction. Accordingly, one cannot complete this paper without discussing possible tests of the idea that humor is a biological IFF. The analogies noted earlier between the properties of humor and military IFFs does indeed support the idea - the properties of humor do parallel those of IFFs. However, the IFF theory is, in essence, a theory of how humans behave in groups and it is desirable to go beyond noting this parellelism of properties and identify evidence that humor functions as an IFF in real human groups. Such functional tests of the IFF theory are likely to emerge from observations made in the human or social sciences - social psychology, sociology or anthropology being candidates.
As one such test, this section will examine a set of observations that emerged from extensive anthropological studies of humor. In particular, it will examine the phenomenon of the "joking relationship." These anthropological studies have been reviewed (Apte 1986; Palmer 1994) and the data used here come from those reviews.
The joking relationship is characterized by the regular exchange of jokes and laughter between the two parties. It is commonly seen as the relationships that form between friends, especially between adolescent males. Anthropologists have studied the distribution of joking relationships in many primitive societies.
The most common form of tribal society is a patrilineal society, in which family descent lines are defined by paternity. Because it is the most common, primitive, human society, the patrilineal structure may be the "wild type" human situation. In such societies, the offspring of a given male grandparent form a family group who will normally be allies in any conflict.
Incest taboos normally prevent marriages between brothers and sisters
or other close relatives so that, in patrilineal societies, young males
normally find wives from other descent lines. Following marriage, the new
wife moves from the family group of her birth to live with and become part
of her new husband's family. In the fullness of time, her children become
part of her husband's family group. It is against this social backdrop that
the distribution of joking relationships will be described. An attempt will
then be made to interpret that distribution using the hypothesis that humor
is an IFF. The pattern is summarized in Figure 3.
Joking relationships do not normally form between members of the same family group. In patrilineal societies, most joking relationships involve adolescent males and, therefore, this paper will concentrate on the relationships formed by adolescent males. Joking relationships are not normally formed within a family group. So, for example, brothers, even if close in age, do not normally form a joking relationship with one another. Joking relationships are formed with friends from other family groups and these are normally within an age group, so that the two parties to the joking relationship are close in age.
Although females can form joking relationships, and do so extensively in modern societies, they form very few in patrilineal societies, probably because, in these male dominated societies, their lives tend to be confined to their own group and such relationships do not form within a group. In patrilineal societies, females often enjoy being the targets of practical jokes initiated by young males, though they rarely respond in kind. These attentions often develop into a joking relationship between the young female and a young male from another group, which may be the forerunner to a closer liaison or to marriage. Once settled into marriage, however, when the bride has moved to live with her new husband's family, the married couple becomes part of the same group and normally lose their joking relationship.
Joking relationships do not normally form between different generation but there is one very striking exception to this rule, which occurs in the relationships formed between an adolescent male and his uncles. In a patrilineal society, an adolescent male does not form a joking relationship with his paternal uncles but, very commonly, he does form such relationships with his maternal uncles. The maternal uncle commonly becomes the target for small practical jokes or minor acts of theft perpetrated by his sisters' male offspring; he is expected to be tolerant of, indulgent of, and even amused by these juvenile antics.
12.1 An Interpretation of Joking Relationships
The idea of humor as an IFF offers an interpretation of the pattern of behavior seen in joking relationships. Firstly, if humor is an IFF, it will trigger only if it is unclear whether the target of the humor is a friend or a foe and if there is some possibility of conflict between the two parties. Therefore :-
1. Joking relationships normally form between neighboring descent lines. They do not form between members of the same kin group. It is already clear that members of the same group will be allies in any conflict and there is no need to interrogate their friend or foe status. Within a descent line, the IFF of humor can be switched off.
2. Joking relationships do not form between members of socially distant descent lines because these two groups would not share enough social knowledge to "get" one another's jokes. Therefore, socially distant descent lines will normally identify one another as foe.
3. Joking relationships mostly involve adolescent males. This social subset is the group most likely to be involved in conflict and therefore the group most concerned by the friend or foe status of other individuals. The joking relationship forms as an interrogation of the friend or foe status of potential adversaries or allies.
4. The joking relationships a young male forms are mostly with young males from other family groups, these being the individuals who are most likely to be his combat allies or foes. Joking relationships do not normally form with other age groups as combat between individuals of markedly different strength or social status is unlikely.
5. Patrilineal societies are very male dominated and females are normally confined within their descent line. Hence, they not generally interrogate the friend or foe status of their contemporaries. However, females are capable of such relationships and adolescent males looking for potential sexual partners will interrogate their friend or foe status so that humor becomes a factor in the early stages of mating pair formation. Under sexual selection, females must find humorous behavior in males attractive, in order that humorous males will be selected and this trait will be reproductively favored.
6. The joking relationship between a male and a female ceases once their union is cemented by marriage and children. Once they have become stable members of the same family group, their respective friend or foe relationship does not need to be continuously queried.
7. The relationship between adolescent males and their uncles is of striking interest. A paternal uncle is an elder in a young male's patrilineal descent line. The two are of disparate age and social status and are linked both genetically and socially. Thus, they are unlikely to becomes foes. Therefore humor, as an IFF, need not query a paternal uncle's friend or foe status and a joking relationship will not form.
A maternal uncle, on the other hand, is part of a different patrilineal descent line from his sister's offspring, since young women change their family group on marriage. Consequently a young male and his maternal uncle are genetically related, on which basis they are likely to be friends, but socially they are more distant and hence are potential foes. A young male can be expected to be very interested in the friend or foe status of his maternal uncles and the joking relationship that forms between them queries this status.
The difference between the relationships formed between young males and their paternal and maternal uncles is an old and striking observation. According to Apte, it has been the subject of much apparent puzzlement and anthropological debate; it does seem to defy biological explanation and, apart from the one offered here, it is hard to see another psychological or sociological interpretation.
In any event, the author is not aware of any other biological or psychological theory capable of interpreting this pattern. Indeed, the data about paternal and maternal uncles seems to be a particularly striking test of the IFF theory. The pattern of joking relationships formed within a patrilineal society thus seems consistent with the idea of humor as an IFF.
All these joking relationships are interesting in their own right. For example, that formed between males and their maternal uncle seems to be the only joking relationship that routinely forms between generations. Consequently this relationship and the motivations that underlie it, deserve study. It may well be prototypical of other, more problematic, inter-generational behaviors, such as the vandalism and loutishness commonly displayed by young males in advanced societies, where the motivations of the perpetrators are far from obvious. Those motivations may, in fact, be quite similar to those leading to the minor practical jokes perpetrated against maternal uncles in patrilineal societies.
13
Summary and Conclusions
This essay concerns the evolutionary origin and social and biological functions of humor. The problem of evolutionary origin has been addressed by recognizing incongruity selection as part of normal sensory information processing. Humans use their senses and brain for social communication. It is argued that, as these faculties have adapted to social life, incongruity selection has become modified to serve social roles and that, in humans, incongruity based selection has come to be expressed as humor. This account of the origins of our attraction to incongruity seems original and quite plausible.
Moving on from origins to function, the central role for humor suggested here is that of an IFF - a device whose job is to direct communications or aggression toward targets or to synchronize learning in a social group. As such it enables people to perceive boundaries around their culture and to perceive individuals as part of or not part of that culture.
The IFF theory seems consistent with each of the following strands of evidence :-
1. The fact that humor is largely confined to humans.
2. The parallelism between the properties of humor and military IFFs.
3. The physiological properties of laughter as an automatic, broadcast response to a joke.
4. The demanding coding properties of humor. That is, the great difficulty of understanding jokes in a language other than one's own.
5. The combination of socializing, friendly inclusiveness of humor and its capacity to aggressively exclude individuals from groups. (It is hard to find another function with links to both friendliness and aggression, to both group formation and group exclusion.)
6. The pattern of joking relationships seen in patrilineal societies, particularly the differences between maternal and paternal uncles.
Hence, it is argued, humor is a biological IFF that uses incongruity-based information selection to determine whether a target does, or does not, share a social knowledge set with the joker. One must be cautious about how far one can extend the parallels between military IFFs and humor - at some point it will break down. Nonetheless extending that parallelism raises the possibility that humor and laughter will serve to synchronize a social group's learning and this may have practical, educational implications.
Those implications might make the classroom a suitable environment for further studies. Observations of the patterns of laughter seen in learning environments might provide a data set that could be used to analyze the information selections and learning taking place in social groups. Correlations might then be found between the relationships between, humor and laughter, the social dynamics of the classroom and the educational performance of the learning group under study.
Finally, this theory for the origins of humor has implications for whether humans are, or are not, subject to group selection. Human social knowledge is, of course, limited by the capacity of the human brain but, as was discussed in section 2.3, if this theory is correct humor is the only known biological IFF that keys from social rather than genetic knowledge. On this basis, human social knowledge is unique in the animal kingdom in that it is not bounded by genetically encoded data. Hence, by the criteria emerging from bioepistemic evolution, the IFF theory of humor implies that humans are a group selected species.
Acknowledgments This article is developed from the Humour Chapter of The Architecture of Thought (Hewitt (2002)). A version of it was presented at the BERA meetings and at the ISS03 humour workshop, both held in Edinburgh, Scotland - September 2003. The author is indebted to attendees at both meetings for their feedback. He is also grateful to Profs. Willibald Ruch and Jyotsna Vaid and to Ann Snowden for their correspondence and advice while writing it.
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