A new perspective on laughter and humor



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          Laughter as an exapted displacement activity: the implications for humor theory

                                 and neuropsychology and neurophysiology in general

                                                           June 2009


                                            Basil Hugh Hall Bsc Zoology (Leic. 1962)



The intellectual journey that ends in a scientifically verifiable theory often begins with many seemingly disparate philosophical musings. This is an essay, rather than a scientific paper as it includes a great deal of  philosophy based on my own observations and thoughts. I have included the philosophy, not only because I believe the studies of humor and laughter are at the stage where they would benefit from some bold speculation, but also because it constitutes the rough map of how I arrive at my ultimate destination - a science based hypothesis.

Note:  There has been some confusion caused by my usage of the word "cultural" in this essay.      

The definition of the word "culture" that comes the closest to its usage is: an integrated pattern of human knowledge, belief, and behavior that depends upon the capacity for symbolic thought and social learning. However, I add my own riders to this definition when I use the word "cultural". In this essay  the word "cultural" covers the subjective aspects of human existence, and although objective, scientific thought is a product of culture (in its broadest sense), I view it as being a step beyond the basic cultural mentality. Science required a different way of thinking and expression through a strictly defined vocabulary and I will refer to "cultural" language – our common, "default" language – to distinguish it from objective, scientific expression.

I also apply the word "cultural" in relation to the "organismal" - the functioning, animal aspect of our being- in the same manner. This highlights the distinction between our interpretation of behaviors in the context of our cultural life and the psychoneural and physioneural (organismal) processes that give rise to them.


In this essay I hypothesize that the laughter elicited by the processing of what we characterize as humorous events is an exapted vocal fight-or-flight displacement response. The circumstances in which displacement activities and laughing occur, and their general physiological effects, are compared, and neurophysiological evidence connecting laughter to "fight or flight" responses is presented. The relationship between laughter and humor is examined and an argument put forward against the use of the word "humor" other than as a heading of a general study as it defies any clear definition that can be meaningfully applied outside its cultural usage. The nature of the basic conflicts that cause animals and humans to indulge in displacement activities is considered in the context of joke structure, content and emotive effects. The endorphin/ laughter controversy is discussed and a possible explanation of laughter's immunological effects is given.

A dictionary of Psychology (Oxford Uni Press) defines the displacement activity as: In ethology, the substitution of a irrelevant pattern of behaviour for behaviour that is appropriate to a particular situation, especially as a reaction to a conflict of motives. Male stickleback fish stand on their heads and dig into the sand as if building a nest when the impulses of attack and retreat are evenly balanced; fighting roosters often peck at the ground between bouts as though feeding; and humans often scratch their heads or perform self-grooming gestures when in a state of conflict, embarrassment, or stress. ( Also called displacement behaviour.)

In line with the wording above, "the substitution of an irrelevant pattern of behavior" and taking into account recent theoretical work concerning behavior, perhaps the phrase "replacement activity" would be more accurate. In this essay the use of the phrase "displacement activity", to describe the physical phenomenon, will be in line with the dictionary definition, with the qualifications that recent theoretical work calls into question the irrelevancy of the behaviors and the idea that the two conflicting motivations are, of necessity, of equal strength. (Anselme 2007,2008) However, the traditional psychoneurological explanation is couched in terms of the displacement of "motivational energy", which is far too vague to have any meaning within the accepted concepts concerning brain function. Anselme replaces the original, simplistic idea of the emergence of a displacement activity as a reaction to mutually exclusive motivations of equal strength with a system involving the interplay of motivational and attentional thresholds. A detailed account of Anselme's ideas is not required here as only the broad implications are relevant to my thesis. In accordance with Anselme's model, I propose that the psychoneurological aspect of what has been termed a displacement activity be defined as the disinhibition of a stereotyped behavior brought about by an attention switching reaction to competing or redundant motivations, which are consequently inhibited.

Recently, there have been other objections to the use of the phrase "displacement activity" as it is often applied to two different phenomena. One is described above, the other is humorously termed " Kick the cat syndrome" - a classic example being the ancient Greeks habit of killing the bringer of bad news. The Greeks crudely solved the problem of the complex and troublesome relationship between reality, emotion and action when, after a reported distant defeat, they inappropriately vented their anger by killing the messenger. It should be noted here that the type of displacement in this Greek example is a psychological rather than a neurological phenomenon as the recipient of the message is expressing the engendered emotion, which in this case is anger - the shift being from a potential target to an inappropriate target. Laughter displacement behavior is of the kind defined in the introduction to this essay, where the shift takes place in the brain and is expressed as a benign, seemingly inappropriate response.

Displacement activities are relatively common among vertebrates, from fish to the higher mammals, including humans (Ingram 1960). They occur when animals have a tendency for two incompatible behaviors (motivational conflict), such as approach and avoidance, or they are thwarted in some way. It is possible these behaviors exist in the lower vertebrates, and in some invertebrates, as a crude method of emotive control - lowering stress during motivational conflict and nullifying persistent emotive brain states when rapidly changing stimuli have rendered them redundant.

The situations that give rise to displacement behaviors in human beings -and in other animals-
 are change, or anticipation of change, in activity, internal conflict, or motivational ambivalence (Schniter, 2001). Laughing and crying fit particularly neatly within these criteria, suggesting that laughing and crying are exaptations of antecedent vocal displacement activities. (Lorenz 1963; Russell 1996; Kozintsev and Butovskaya 1999) The motivational ambivalence and internal conflict aspects of the phenomenon are suggestive in explaining the efficacy of the particular structure of jokes in precipitating laughter.

                                                                                                                                                                                                                       This essay is primarily concerned with the nature of laughter and humor, but a description of the nature of crying is required here as although laughing and crying are normally considered as indicating states of positive and negative valence, I view their evocation as being indicative of, and instrumental in, the modulation of the states of fear and aggressiveness respectively.

Although it is not generally acceptable to compare the functioning of a human infant's brain to that of a hominid's brain, the fact that the human infant lacks the emotive control of an adult, has a poorly developed cognitive system and little cultural experience, it would be expected that a basic vocal displacement activity is expressed in its purest form in early childhood. As children initially lack language, and for some time the ability to act independently, the communicative aspect of non-verbal vocalizations is particularly important at this stage of our development (Soltis.2004). Human infants cry from birth and laugh after a few months of life. Crying has an obvious survival value in that it induces adults to attend to the infant and supply its basic needs, and this attendance to crying individuals extends into adulthood.

An animal's basic survival strategies lie within the gamut of approach and avoidance motivations in which action is mediated by the neurohormonal responses we characterize as aggressive and fearful states. Most of us rarely face a full blown "fight or flight" situation in our daily lives and we do not immediately associate our everyday pursuits with an aggressive state of mind, but to move towards a goal demands a degree of aggressiveness. When our aims are thwarted we may react by raising the level of aggressiveness (increasing vigor) in order to remove or bypass whatever is in the way of the desired result.

In this essay I do not limit the use of the word "aggression" to forceful physical and verbal attacks, but in accordance with R.J. Rummel's ideas, where aggression is viewed as a spectrum of behaviors unified under the concept of self-assertion.  (Rummel R.J. 1977)  The application of the terms "fear" and "aggression" as singular concepts in descriptions of behavior in lower animals is acceptable. However, a singular concept of aggression becomes simplistic when applied to the functioning of the human brain where there is an acute recognition of the self and the self's interactions within a social group. Rummel views human aggression as taking various forms: Identive, assertive, forceful, coercive, bargaining, intellectual, authoritative,   altruistic and manipulative, (van der Dennen 1980) and although only the first three are applicable here, such distinctions can explain the various contexts in which crying occurs. 

Although some features of crying can be found in other species, it is an acute awareness of the self in human beings that makes crying a phenomenon peculiar to our species. Any perceived diminishment of, or opposition to, the self can result in crying; as can a sudden redundancy of self assertion or, in certain circumstances, the absence of an appreciation of the self.                                                                                                                                                                                                                               Both crying and laughing are innate (stereotyped) behaviors that are activated by disinhibition. I define the neurological basis of crying as the disinhibition of a stereotyped behavior in response to the opposition or redundancy of neural processes responsible for the expression of positive (assertive) behaviors or when appropriate positive reactive behaviors are lacking in our repertoire of responses.

The crying of young children is easily explained in these terms: young children cry when they are prevented from taking positive action, either due to direct blocking or by a change in circumstances. Children will react aggressively to the loss of objects to playmates, and if their attempts to retrieve the objects are thwarted, their response is a communicative and alleviative bout of crying. The cancellation of an enjoyable event will also bring a child to tears as the anticipatory and motivational neural activity becomes redundant when a specific, desired future is denied.

Adults do not cry as often as children as they have greater control over their emotions, and having greater knowledge and a larger range of responses, can rapidly change their points of view and build strategies to change or bypass undesirable situations. Most adults do cry when bereaved. When a spouse dies, a mate and a companion is lost - so is a specific future - and although it may seem inappropriate to connect this type of loss with aggression, its presence is betrayed when some bereaved individuals state that they are angry at the deceased for leaving them. Crying during a period of grief can be viewed as being instrumental in the dismantling of the emotive underpinnings of cognitions concerning the past, present and potential future of the deceased. The memory induced emotional response is alleviated during the act of crying, which may serve to slowly bleed memories of their painful emotive impact.

The ideas expressed above adequately explain why some individuals, when in a state of anger, begin to cry when they are prevented from fighting, but how can the crying of a triumphant sportsman, or that of an individual witnessing an act of forgiveness, be explained in terms of aggression? The crying of the sportsman is the easier of the two to comprehend as he indulges in ritualized aggression, and once the focus of his aggression is removed by the act of winning, the tenaciously held aggressive mind set that was necessary for success becomes redundant in the new circumstances in which he suddenly finds himself. The second example has to do with our ability to empathize. For most of the time, and for most people, a mildly aggressive mind set is the norm (identive and assertive aggression , Rummel 1977) , as this is necessary if we wish to be taken seriously and not be abused during social interactions. When individuals are wronged they generally react in an aggressive manner, but a genuine expression of forgiveness communicates a retreat to an appeasing, non-aggressive state. When witnessing an act of forgiveness, and empathetically entering into the situation, our normal level of aggressiveness can suddenly become redundant, resulting in a tearful response.

It can been argued that the crying of young children when hurt or frightened has nothing to do with aggressiveness, and although the redundancy of an aggressive mind set might explain why some sportsmen cry upon winning, why do other individuals cry, for example, the winner of the first prize in an art competition? Such questions highlight why coherent theories concerning crying and laughing have been so difficult to elucidate. The seemingly unfathomable complexity of the phenomena is the result of our line of approach - we have tended to ask why human beings laugh or cry in specific circumstances rather than what are the natures of crying and laughing that lead to their evocation during certain types of events. Individual human beings should be at the center of the study - the evolution of their collective human nature, their specific mental characteristics and the natural changes to these, over the long and short term, that bias their responses to stimuli. To obtain a clearer picture of the situation, and to answer the objections to an aggression theory of crying, the following must be taken into consideration.

a) Both crying and laughing have two distinct aspects: a neurophysiological aspect - the reduction of emotive brain activity, which lowers stress levels, and a behavioral aspect - the communication of mood and need, by facial expression and vocalization. The relative significance and importance of these two aspects changes with age - the communicative aspect being of prime importance in early childhood.

b) There is a tendency to consider aggressiveness only in its most extreme form, but projecting your mental and/or physical self into a situation means that you are acting in an aggressive manner. The same can be said when you strive to attain a personal goal or attempt to change a situation or a person's point of view.

A full blown aggressive state is not required to induce crying in competing individuals when winning has made such a state redundant. As anyone who has entered a competition that required a great deal of physical and mental effort knows, the will to win and be pronounced the best is a powerful driving force, and for certain individuals, but not all, this highly emotive state of mind can give rise to tears when winning has made it redundant.

c) There seems to be a large number of events that cause human beings to laugh and cry, and the search for causes has often centered on the events rather than the individuals involved. There is not a large number of events with completely different natures but rather a variety of individual responses to these events. Whether an individual laughs, cries or is left unmoved by an event depends on the individual's sex, age, ethnicity, body type, intelligence, culture, knowledge, experiences and all the other physical and mental characteristics that make them a unique individual. Their emotional state at the time of the event and their basic long term emotional state will also affect their response.

Individuals with a tendency towards passivity and individuals who tend to be aggressive may well react differently when presented with the same stimulus. While observing a group of women looking at photographs of babies I noticed that the two most aggressive individuals did not respond with joyful laughter but had tears in their eyes. These two individuals, known to me personally, both had healthy children and grandchildren with whom they had a good relationship. Neither of these women had been physically or sexually abused, but their aggressiveness was born of traumatic events involving individuals to whom they had been emotionally attached. Although the events had occurred in their distant pasts, they were still bitter; they often mentioned the people and the events and were prone to criticizing individuals they did not like and generally complained whenever an opportunity arose. This aggressive mind set became redundant when they were faced with images of babies.

d) A coherent exposition of the natures of crying and laughing has been hampered by the fact that researches did not initially recognize that the basic crying and laughing processes have been exapted over time to serve different functions. As will be seen in the next section of this essay, this is particularly true of laughter. It appears that the crying process has limited application in other areas of human behavior and it remains for the most part an involuntary non-verbal form of communication.

 To return to the question: If the neurological process of crying is defined as the disinhibition of a stereotyped behavior in response to the blocking or redundancy of the neural processes that mediate aggressiveness, then why do children cry when they are startled or physically hurt? Adults do not cry as often as children, not only because they have greater control over their emotions but because they can, and are expected to, act in a manner that resolves the situations which have given rise to their discomfort. The crying of babies and young children is a special case because in difficult situations they act by proxy. They do not have the physical ability, nor the knowledge or repertoire of responses, to take appropriate actions when faced with novel events. They cry because they are helpless, and this non-verbal communication, whether it is a response to hunger or hurt, is interpreted by adults as "Do something!". When, as adults, we are bereaved we return to a childlike state. There are no actions that can be taken to avoid death. We cry when we are bereaved for all the reasons outlined above and because we realize that there is nothing we can do to bring the dead person back or prevent our own demise. Like young children, we have no effective response in our repertoire for this situation.

Finally, a comment on crying when people experience an "oceanic feeling". Crying which is accompanied by what has been called an "oceanic feeling" often lacks a vocal aspect. This is also true of empathetic crying mentioned above. Is the audible, communicative aspect often lacking in these two cases because the crying is "personal" and does not necessarily require the attendance of another human being? Whatever the answer to this question, the central thesis holds: the oceanic feeling and attendant crying result from an abandonment of the striving ego - a relief from Rummel's identive and assertive aggression. It is a response to the giving up of the self to some transcending agency, or losing the self in some all-consuming experience, as when an individual contemplates the sacred or listens to a highly moving piece of music.

As mentioned earlier: "For most of the time, and for most people, a mildly aggressive mind set is the norm, as this is necessary if we wish to be taken seriously and not be abused during social interactions". Identive aggression is defined by Rummel as: "an offensive manifesting of being, an unconscious thrusting outward toward reality of our physical or psychological dispositions, of our individuality. Physically, this may be our size, manner of movement, and appearance; psychologically, our temperament and unconscious needs." Identive aggression is basic, and because we do not sense its existence, as we might a flush of anger, we do not comprehend that it exists within the gamut of aggressive states. Its presence in our basic emotional make-up is only apprehended by a recognition of its absence during an oceanic episode.



 At first glance, laughter appears to be less important in our behavioral repertoire than crying. However, as human laughter has its counterparts in the laughter-like behavior in the apes (Davila-Ross and Owren, 2009)  (Provine 1996), it is likely that the evolutionary forerunner of human laughter was of value in intraspecific interactions in  some primate groups including our hominid  ancestors. ( Some researchers extend the occurrence of this phenomenon to other mammals, including rats.( Panksepp 2003)  

The neural processes that produce the laughter vocalization in humans I consider to be the same as those in animals that produce similar vocalizations, but the underlying psychoneurological processes that elicit laughter I view as having changed with changes in the complexity of the hominid cognitive and emotive systems. The origins of human laughter can be traced back to the play fighting of primates in which the reduction of emotive neural activity during bouts of vocalization allowed them to practice maneuvers without harming each other.

The circumstances in which chimpanzees "laugh" are limited to play-fighting, tickling and chasing, and although the "this is an attack / this is not an attack" conflict may have laid the foundation for the joke format, it is obvious that the variety of circumstances in which humans laugh requires further explanation.
The whole question appears to center around the brain's processing of conflicting cognitions and emotions, and I propose that play-fight vocalization was exapted in the hominid line to include the disinhibition of the basic laughter response during decision making, particularly in fight or flight situations. Later, with the advent  of language, it appears that laughter was disinhibited whenever verbalizations threw up irresolvable  cognitive and emotive conflicts.   (
Kozintsev A and Marina Butovskaya)   (The present wisdom, which this essay challenges, is that laughter is a response to the incongruities (conflicts) being resolved)

Each habitat demands specific survival strategies from the animals that occupy it, and once our hominid ancestors began to spend time on the open grasslands emphasis would have been placed on certain behaviors. The strategies for food gathering and defense in the forest differ greatly from those on the grassland, where a change to a more omnivorous diet and a lack of immediately accessible escape routes would have meant the need for greater cooperation and a unifying system of control within the hominid bands. It is significant that the forest dwelling Bonobo chimpanzees live in loosely organized, female dominated groups (Stanford, C. 1998) but in line with most ground living primates, the hominids were probably led by a single experienced alpha male. In open country, it would have been essential for the alpha male to rapidly assess the severity of threats so as to deter any premature action on the part of individuals that might precipitate an aggressive response from potential predators. A novel event, or one perceived as potentially dangerous, would have induced a fear response in all the apes, including the alpha male, but in situations where no immediate fight or flight response was perceived by him as appropriate, an audible and contagious displacement activity would have been particularly effective in calming the members of the band and preventing panic scattering. (Ramachandran 1998)                                                                                                                                                                                                                               In line with ideas concerning laughter in modern Homo sapiens, as well as being a useful tool in inter-specific interactions, a contagious staccato vocalization displacement activity would have been effective in calming individuals during intra-band conflicts. In these situations Bonobo chimpanzees employ sex as the displacement activity (de Waal 1995).

It is generally accepted that staccato vocalization (laughter) existed long before the advent of language and the cultural aspect of our evolution it was instrumental in bringing about.( Gervais and Wilson, 2005) In the past, emphasis has been placed on the study of laughter inducing, verbal constructs within the adult cultural milieu, but if we are to fathom the true nature of what we call "humor", we must first explore other avenues of study that have a bearing on the natures of laughter and crying. Headway in these endeavors has been slow, due to a top-down approach, which, at times, viewed laughter as being an almost incidental response during the processing of "humorous events".

A top-down approach immediately runs into problems as it becomes bogged down in the seemingly unfathomable contextual complexities of adult human laughter and is further compromised by a failure to recognize verbal humor induced laughter as an exaptation of the basic laughter process. Humans have greater emotive control and a massively more complex cognitive system than their hominid ancestors, and it is these changes in our emotive and cognitive systems that have produced the complexities that mask the basic nature of laughter. When the different types of laughter, and the different contexts in which laughter occurs, are considered, it appears that the basic laughter process has been exapted to serve different functions in the line of hominids  that gave rise to modern  Homo sapiens. As laughter predated language in our evolution, it is obvious that verbal humor plugged into a response system that already existed. It is therefore my contention that we will arrive at an appreciation of the phenomenon we have termed "humor" by studying laughter. This means that we must start with the neurology of laughter and work upward to cognition and linguistics, and on a temporal level, begin with our hominid ancestors, and using the data we have on laughter and stress, attempt to map out its development.

In this essay I define the basic neurological aspect of human laughter as the disinhibition of a stereotyped behavior in response to the opposition or redundancy of the neural processes responsible for the expression of negative (fear-based) behaviors.

Unlike crying, where the precipitating stimulus is normally an actual, or a memory of an actual, highly emotive external event, laughing is often a response to internal motivational conflict, or in a similar manner to crying, a sudden redundancy due to changes in circumstances. With the exceptions mentioned below, laughing normally only occurs during an event if the degree of fear being engendered does not swamp the opposing motivation, in general, limiting laughter to cases where the danger factor is low, or perceived to be so. In circumstances when the danger factor is high, or perceived to be high, people may laugh immediately after the event.

Our organismal reaction to falling is fear, and a young child's screams of laughter when being tossed into the air by a trusted adult is an indication that the fear response is being opposed by the child's tacit knowledge that he is in no danger. If the child is tossed by an adult with whom he is merely acquainted, he may not laugh at all, and as his fear level rises unopposed, his response becomes a communicative crying for help.
How do we account for the facts that some individuals laugh when in extreme danger, and some Cambodians, having escaped Pol Pot’s reign of terror, reacted with laughter when told of further atrocities? At times, a general state of nervousness can be relieved by a short, spontaneous burst of laughter, probably facilitated by a small window of opportunity brought about by a momentary cognitive shift (a change from one line of thought to another (Latta 1999)). Nervousness, a muted expression of fear, is a common enough feeling that builds up before we face challenging events. Extreme fear is distinguished not only by its intensity but by the fact that the fear evoking situation is not usually expected and is so beyond the normal it can seem unreal - "It was like being on the television", as some people say when they have been in unexpected and dangerous situations. During the ordeal, others might say, "This isn’t happening!", or, "You’re joking !". The brain will perform all sorts of maneuvers to escape a dangerous situation, even to the point of denying that it is happening. Some people are more prone to denial than others, and they are the individuals whose brains attempt to view distressing events as though they belonged to a different dimension. Again, it is a cognitive shift, from an appreciation of the event as real to a fictitious interpretation, that presents a time window in which the emotive neural activity of the fear response is alleviated by a disinhibitive release of laughter.

For those of us who live in comfort in the West, a report of an atrocity taking place on the other side of the world can produce a large emotive response as such events are not the daily norm. We do not react with fear, as we are unlikely to suffer the same fate, but with anger, which, in the more sensitive of us, may give rise to tears, and we naturally expect that the Cambodians would have reacted in a similar manner. The response of the Cambodians, who had lived for a long period of time in helpless resignation, would have been the rekindling of fear, and in people for whom fear had become the norm, the displacement behavior was laughing, not crying. Although children in South East Asia are taught to laugh when feeling sad (Frye and McGill 1993), inappropriate laughter that takes place in tragic circumstances, and seemingly causeless spontaneous laughter, are typical of individuals suffering from long term stress, as in the 1962 so-called Tanganyika epidemic when, over a period of six months, groups of people indulged in incapacitating bouts of laughter.(Hempelmann 2007).

The occurrence of inappropriate laughter illustrates how the responses to emotionally charged events vary widely from person to person. There are people who laugh inappropriately all the time. The English essayist, Charles Lamb, in a letter to a friend, confessed, "Anything awful makes me laugh. I misbehaved once at a funeral." A young woman of my acquaintance related how she had laughed when informed of the death of a friend she had seen just the night before. This is an example of denial laughter, but she also told me of another incident in which the inappropriate laughter arose from a different source. At a tennis match she became irritated by a spectator behind her who grunted every time the ball was hit. She turned round to  find a man, who obviously suffered from cerebral palsy, grunting with the effort of moving his head. She is a caring person, who works in a hospital, but she had turned away and suddenly burst into laughter. 

There is a broad diversity of responses to reported disasters, hardship and deaths. The intensity of our feelings in response to these events depends on how emotionally close we are, or were, to those involved and our individual ability to empathize and sympathize.

It was only a few weeks after the crash and loss of Donald Campbell, while attempting to better the water speed record on Coniston Water, in 1967, that people began joking about the event. 

"They’ve found Donald Campbell. Yeah, he came out of a tap in Manchester."

Few jokes emerged following the death of Princess Diana in a road crash in  France. Diana’s image, however manufactured by herself and the press, evoked a highly emotive response in many people who would have considered the telling of a joke about her death an act of sacrilege. The ability to laugh freely at a joke requires a certain degree of emotional distancing from its subject. This distancing may be passive - being separated from people and events by time and space - or active -mentally and physically distancing ourselves from people and things we do not like or wish to consider. For those disturbing events in which we have been personally involve, the  distancing can be brought about by time. "Next year you’ll be laughing at  all this", is part of the comforting advice we sometimes receive from friends when we are experiencing difficulties in our lives. The measure of distancing is the intensity of feeling we experience when we recall a particular event and we can view repression as the ultimate form of distancing. 

People laugh a great deal in social situations and especially in the presence of their friends. The ability to respond to certain events by the disinhibition of staccato vocalization probably enabled our hominid ancestors to lower stress to levels appropriate to the situations in which they found themselves, and social laughter performs that function today. Although our normal activities require a mildly aggressive mind set this does not mean that on an organismal level the environment is not continually being tested by the brain areas that mediate fear. Long before we are conscious of certain aspects of the environment and bring our cognitive faculties to bear on them, the limbic system of the brain has already interpreted the situation in terms of basic responses and determined the appropriate level of emotional activity. However, our prefrontal lobes are capable of inhibiting these responses if they are perceived to be inappropriate. 

From the time the animal world shook off the shackles of limiting stereotypical responses, it was faced with the problem of greater choice, and thus ambivalence and vacillation. The evolution of language and abstract thought only complicated matters as it greatly increased the field of possibility and our ability to imagine and fabricate (Kozintsev and Butovskaya 1999). When intelligence took over from instinct as the primary tool for dealing with the world, the new mental and physical experiences, made possible by our developing brain, required a new response to novelty. If experience did not fully allay our fears concerning particular objects and events we demystified them by naming, ritual, interpretation and rationalization. The answer to ambivalence, doubt and fear was culture - a commonly held, and vigorously defended, system of ideas that lays down the way members of a group should think and behave. The cultures into which we are born are mental constructions, designed to maintain order and hold fear at bay.

As we confidently act within our self-made mental and physical environments, functioning in the background, and for the most part denied access to consciousness, is part of the brain that is still interpreting the world in organismal terms of survival. This means that we are much more anxious and defensive than we acknowledge when coming into contact with other people. There may be an under-current of physical threat when meeting a large stranger, and as we have, in most circumstances, adopted words instead of actions to express ourselves, we are guarded in what we say and highly sensitive to what is said to us.

Many people laugh when they talk to babies. The probability is that their normal defensive brain set is found to be at odds with their knowledge of these small and defenseless individuals. We exhibit a similar relief response when we meet friends. The normal defensive and readiness emotive states become redundant when we are in the presence of people we know well and trust. The laughter of a young child on the return of a primary caregiver after a short separation can be viewed in a similar light. The reappearance of a trusted individual makes the neural activity underlying separation anxiety redundant - the child's laughter nullifying the fear response and also inducing laughter in the caregiver, which aids in the reaffirmation and strengthening of mutual bonds.

Duchenne and non-Duchenne Laughter      

A mention must be made here of Duchenne and non-Duchenne laughter. Duchenne laughter/smile, named after the French neurologist  Guillaume Duchenne, is seen as being involuntary whereas non-Duchenne laughter is a more controlled form of laughter which lacks an emotional basis. However, non-Duchenne laughter is such a natural  part of our conversational vocalization that we do not normally appreciate the distinction. The laughter of game-show hosts and salesmen is often of the non-Duchenne type. It is thought to have developed to allow hominids to use its affect-inducting properties to strategically influence others in social interactions. ( Gervais and Wilson, 2005)

There is disagreement among researchers concerning which laughter evoking events should come under the heading of humor. I agree with Provine (Provine2000), when he views the laughter of friends when chatting as not always being laughter of a humorous type ( the mechanism of its evocation differs from that of a joke), although we do describe such situations, in cultural terms, as "good humored". During a meeting of friends much of the laughter would be of the non-Duchenne type. However, even in the absence of any verbal exchange that engendered conflict in the brains of the participants, some of the laughter would be genuine, Duchenne laughter, especially when the participants initially meet. This would come under the "change of activity and situation" heading; and there might be some "humorous" laughter if, as young men are wont to do, they insulted each other and engaged in mock fights.

I view laughter in modern Homo sapiens as an exapted fight or flight displacement activity which has been co-opted by different systems in the brain to serve different functions. Duchenne laughter takes place in a variety of different situations, but if I were to use the word "humor" in a classification of laughter evoking events , it would be limited to those that induce conflict which is then nullified as the result of the disinhibition of the laughter process. There would also have to be a further distinction between physical and verbal "humor", between slapstick and joking. Again, if I were to use the word "humor", it would not cover all the pleasant situations in which laughter is elicited. I would not view some situations where laughter is induced as belonging to humor, such as when  drugs and alcohol cause spontaneous outburst of laughter. There is also an aspect of intentionality in deciding whether an event is viewed as humorous or not. Is a man slipping over and evoking laughter in those observing him to be viewed as a humorous event merely because it evoked laughter, or can the event only be classified as humorous if the man, or a clown, intentionally slips over?
The problem with the concept of humor  
Before we can apply the idea of laughter as an exapted displacement activity to humor theory we must first strip humor theory of its excess conceptual baggage and dispense with the erroneous assumptions that have, for a long time, hindered progress in the field.

When individuals assert that they have formulated a theory of humor it can mean:

a) The theory defines what the authors view as the essence of the phenomenon they term "humor" - what they believe humor to be.

b) The theory describes/explains what the authors view as the most important aspect of what they have termed "humor".

c) The theory describes/explains what the authors term "humor" on an isolated level; on a linguistic, sociobehavioral, psychological, physiological or neurological level.

d) The theory is based on all, or some, of the above.

Much time and effort has been spent in attempts to define humor and fashion humor theories. Most humor researchers now accept that there can be no definitive exposition of the nature of humor, but there is still disagreement as far as humor theories are concerned. This, again, is due to a top-down approach to the topic. When considering the nature of jokes, the space/time frame that should be applied extends further than the functioning of the individual’s brain that is processing them. The individual might comment that a joke made him laugh - the joke was the cause of the laughter, the joke preceded the laughter - but when we enlarge the space/time frame and consider the evolution of the systems in his brain that process the jokes, then the picture changes. We would not tell jokes if they did not give rise to laughter and a feeling we describe as pleasurable, which has been shown to accompany a decrease in stress levels and muscle tension. In fact, the word "joke" would not exist, as we distinguish the joke from a statement, story, puzzle or piece of nonsense, not only by the context in which it is delivered, but by its bodily effects. The laughter process preceded language in our evolution and so we can say it is the laughter process that is the cause of the joke (and that particular type of humor) in so far as the existence of the joke is dependent on the existence of the laughter process and its general form predetermined by the laughter process.

The terms "humorous" and "funny" are often applied as though they represent attributes of the joke itself; however, their meanings cannot be extended further than the idea that a joke triggers mirthful laughter. Mirthful laughter often accompanies situations that are harmless and inconsequential, and events and pieces of writing that are designed to distract and amuse ( but do not necessarily induce laughter) have all been placed in the "humor box", along with jokes and other mirthful laughter evoking situations. The "humor box" contains loosely related phenomena, some that elicit laughter and some that do not. This includes intentional and unintentional humor, joking, slapstick, light-hearted articles, sarcasm, irony, non-serious plays that are classed as comedies, serious plays (black humor and satire) that use exaggeration and ridicule to put forward serious ideas, which, as a group of phenomena, constitute a non-centered network of relationships, the outer limits of which may have very little in common.

Humor cannot be defined by the content or nature of the events to which we have attached the term and so researchers have been unable to find a concrete unifying feature within the set of things designated as "humor". One of the clearest observations concerning this problem is to be found in a message from Médéric Gasquet-Cyrus published in an online forum in 2002.

"Of course, saying that "humor doesn't exist" is a methodological point of view ; we must prove the occurrences of humor, each time it appears. I think that many scholars have made a confusion between the word "humor" and the wide range of events occurring in everyday life, in literature, in arts, etc., labelled "humor" by human beings. Of course, "humor exists"... but is there only one way to define it, to define its mechanisms ?... I'm not sure of this. As we all know here, all the definitions proposed by all scholars (from Antiquity to nowadays) don't explain the phenomenon at a moment or another. Because there is no ONE essence of the phenomenon nor ONE definition which explains it ." Médéric Gasquet-Cyrus (University of Aix-Marseille/France)

Although they cannot define it, most people believe they know what humor is. They also know what furniture is; but if an attempt is made to fathom the essence of furniture by considering what a black metal chair and a varnished oak wardrobe have in common it will fail. On a cultural level, the dictionary definition of furniture: The moveable objects that are used to make a room or building suitable for living or working in, suffices. However, there is no essence of furniture, no commonality of color form, material or function. There is of course an essence of each type of furniture, as there is an essence of each of the phenomena we have lumped together under the heading "humor".

To say we laugh because something is humorous, or funny, is to make a circular statement, and to say that we "experience" humor, or humor "takes place", is nonsensical. Humor is a mental construct,  a categorical concept, and along with the word "funny" belongs to language of the cultural milieu. The word "humor" should only be used to denote a general area of study and never in a descriptive manner as its application lacks the rigor demanded of scientific usage. In this essay we are dealing with the type of humor that is defined by its reliance on the existence of a specific displacement activity. Within the general study of humor, laughter evoking events are the only clearly definable forms, and the only forms whose processing progress can be mapped from their neural substrates through to their sociobehavioral effects. 

When all the self-inflicted complications have been peeled away, the central and most pertinent question is: why do certain utterances, pieces of writing and events induce people to break out into the staccato vocalization we have termed laughter? Working from the assumption that laughter is a form of displacement activity, the answer to this question requires that a link be forged between the motivational conflicts of our hominid ancestors, in response to real and external stimuli, and the processing of laughter inducing events, often of a fictitious, verbal nature in modern Homo sapiens.

Pleasure, pain and stress  

As laughter is usually associated with pleasure - seen as causing, or expressing, a feeling of pleasure - an examination of the nature of pleasure should give further insight into the nature of laughter. Ask people what activities they indulge in for pleasure and the list you collect will be extremely long and the entries diverse. Some activities can only be enjoyed on ones own, others in small or large groups. Many activities are goal oriented, others are not. Some require a large mental input, others are physical, and some have both mental and physical aspects. One person may find another person's pastime irritating or even painfully boring and any attempt to discover a common positive element in all the activities, other than the participant's insistence that their pastimes are pleasurable, will fail.

The quality of the feeling of pleasure experienced while indulging in pastimes also varies. We cannot compare the exhilaration felt by the sportsman to the excitement of the birdwatcher when he sees a rare species, or the tranquility of the individual reading a book on the lawn on a bright summer's day. The unifying aspect of pleasurable activities seems to be encapsulated in the comments, "It takes me out of myself", and, "I lose myself in it". The unifying element is not to be found in the activities themselves, but the ability of the activities to afford the mind an escape from the self and all its attendant anxieties. It appears that the only unifying aspect of pleasurable pastimes, which is not subjectively based, is a negative one - the deflection of mental activity away from brain areas that engender stress.

The following may appear to be a truism, but at least one requirement for us to experience what we have called "pleasure" seems to be the absence of pain ( in the processes and situations to be considered here, meaning mainly emotional pain, fear, anxiety, remorse, sorrow, etc.) The next question that must be asked is whether the absence of pain is the only requirement for a feeling of pleasure to be experienced? Although we view pleasure as being positive (desirable), the possibility is that, in a neurological sense, it is negative. Pain can be viewed as the positive of what we regard as the pleasure/pain duality, and pleasure the conscious appreciation of a change in brain state brought about by the fulfillment or inhibition of the motivations that sustain the neurohormonal correlates of stress. In other words, emotional pain is the conscious appreciation of being over stressed and pleasure the conscious appreciation of the lowering of stress (Becerra, L et al 2001). It is possible that the rats, in Olds' classic experiments of the fifties, were not registering what we have erroneously characterized as an entity, "pleasure", but were locked into the continuous, stressless, end game of the stimulus-> response-> satisfaction, sequence. They may have continued to press the lever that sent an electrical stimulus to the septal area of their brains because it immediately induced the neurochemical correlates of satisfaction and left lever pressing as their only motivation. Recent research suggests that dopamine is not the "reward" neurotransmitter, as once thought, but mediates for "wanting" rather than for "liking". It is very easy to mistake obsessive wanting for liking and therefore assume that approach movements are influenced by anticipated "pleasure" (Winkielman et al, 2003; Pecina et al, 2003).

If those of us who are in an advanced state of decrepitude concentrated on our bodily and mental states we would be able to come up with a whole list of sensations such as: a slight tooth ache, an old wound giving pain, arthritis in the knuckles, a slight feeling of anxiety accompanied by visceral activity. We are distracted and unaware of such sensation for the greater part of the day. Now, if all the sources of these sensations were somehow shut down while we were in a normal state of distraction, there is little doubt we would immediately register the change and report it as a pleasant feeling.

The reports of pleasurable feelings induced by drugs generally fit into the categories of "enlivenment" and "euphoria". There is a difference between a report of an event being pleasant and a report of feeling pleasure. Enlivenment may be reported as pleasurable, but the feeling of enlivenment is not the feeling of pleasure. Without the attributes of a complex event to complicate the situation by introducing psychological biases, or concomitant feelings to which we can attach the word "pleasurable", a drug induced feeling of euphoria is probably as close as we can get to an unadulterated feeling of pleasure. The anterior cingulate cortex is one area of the brain where physical and emotional pain are registered (Panksepp 2003). It is also a site of the analgesic action of opiates, the administration of which typically induces the stressless state we call euphoria. The jury is still out concerning the secretion of an opioid as a result of a bout of laughter, but if this turns out to be the case, then it is possibly the source of the pleasure people report during laughter evoking events.

Although stress is sometimes, and erroneously, viewed in terms of arousal, the aspect of stress most pertinent to the study of laughing, crying and humor is stress in relation to action. Although the lay person may immediately associate emotions with feelings, feelings merely signal that neurohormonal changes are taking place. A distinction must be made between the motivation to action (emotive brain activity) and the appropriate bodily responses (arousal) to effectively carry it out. We enter a state of high stress when this neurohormonal readiness is maintained for long periods of time, or is continually being induced, but denied expression in action. We are in a continuous state of stress as the brain's cognitive mapping of the environment is matched by an emotive mapping, which interprets cognitions in terms of potential action. Emotive activity is taking place all the time as it is necessary for appropriate decision making in response to cognitions, but the brain works on a "need to know" basis, and because we associate emotion with specific feelings, for most of the time we do not appreciate that emotive processing is taking place.

It can be seen from the four quadrant model of mood, below, that pleasure is associated with the lowering of stress, and mental pain with the increasing of stress.

High arousal and high stress (anxiety),

High arousal and low stress (pleasant excitement),

Low arousal and high stress (boredom),

Low arousal and low stress .(relaxed drowsiness).

(After Cox and Griffiths 1995)

We report the most pleasure when arousal is increasing and stress is decreasing. Children will exhibit the exhilaration we have called "unbridled joy" when indulging in activities that cause a fear response which is quickly opposed by the knowledge/faith that they are in no danger; as when they are being chased or tossed about.

I view neither laughter (which is sometimes cited as an emotion in popular writing) nor exhilaration as emotive states. Laughter could in fact be viewed as anti-emotive as its evocation is instrumental in nullifying emotive activity, and exhilaration as a conscious appreciation of the effects of the hormones and neural transmitters that sustain arousal, again, when stress is decreasing. The same arousal state can be deemed to be pleasant or unpleasant depending on whether stress is decreasing or increasing. A first skydive only becomes exhilaratingly pleasant when you realize you are not going to die, and the mountaineer is only truly exhilarated when his goal is reached, and the arousal necessary for the attainment of his goal is separated from the stress engendered by the fear of failing or falling.

An individual's history is not just an archive of cognitions but an archive of cognitions with emotional underpinnings that give them meaning on both a cultural and organismal level. The past, present and future are all mapped out in this manner, and all have the potential to induce high levels of stress. Actions that should have been taken in the past, anger that should have been expressed, things that need to be done immediately, but are deferred, and things to be done in the future, that may involve difficulties, all give rise to stress because, for various reasons, action is, or has been, denied. As we go through life we build up what might be termed an "emotive debt", event specific, unexpressed emotions that are continually reawakened, but not necessarily brought to consciousness. In extreme cases, this can lead to physical and mental ill-health (Merali, M. 2007) and precipitate drug addiction (Cuomo, C, et al. 2008), or if the emotions are inappropriately expressed, to prosecutable acts, as in the cases of abused children becoming abusing adults ( Campbell, D, et al. 2001).

Action, cognition and language    

Most of the papers written on the subject of humor concentrate on the nature of verbal humor, and its social and medical effects. Not all humorous events entail language, but if we are to fathom how language in a particular format evokes laughter, we must first grasp the connection between language and the reality we believe it conveys.

If our cognitive systems, in concert with our emotive systems, are to act as efficient agents of our survival they must, for most of the time, convey reality with a fairly high degree of accuracy. Our ability to consider situations and plan future actions demands that reality is somehow simulated in the brain, which, during our evolutionary history, would have entailed the development of a system that utilized processes that facilitated meaningful movements, such as body maps and stored sequences of muscular contractions (Cruse, 2003).
Like a flight simulator, which never leaves the ground, the brain is able to simulate, without actually instigating action, and so is able to practice, plan and invent. Language represents a natural progression as it is an extension of this initial exaptation. The development of language did not require a completely new system of neural processes as it arose from the association of sounds with aspects of the world that continued to exist in a simulated form even in their absence. In the beginning, language may have described the world in metaphorical terms, but finally, when, through feedback, our ability to conceptualize reached the point where we could contemplate language itself in terms of cognition, we developed logical thought by a further separation of cognition and emotion.

Language, even in technological societies, lies closer to that of the hunter-gatherer than the logician, and as Pinker (1997) has pointed out, we use space and motion as a metaphor for abstract ideas, even when describing things that are static, as in the sentence, "The bruise went from dark red to black". This is not surprising as language conjures, and is conjured by, a simulation of a reality defined by movement and change. Language has meaning on both semantic and emotional levels. Different situations have different emotional flavors and are mapped in terms of potential and appropriate action. Verbal communications are mapped in a similar manner, the emotional flavor changing in response to the ideas expressed, like an appropriate musical backing to the lyrics of a song.

Specificity is relatively new development in the evolution of cognitive systems and is a function of language. How new is demonstrated by our continuing use of metaphor, and more specifically by words such as "glas" in Welsh, which covers shades of green, blue and gray. There is a word in Japanese that is used in a similar fashion, "aoi" , which means green, blue or pale -presumably because vegetation and the sky are the continuous backdrop from which highly colored flowers, birds and insects stand out. Some New Guinea Highland languages have terms for only black and white. The separation of colors from contexts is obviously relatively new, and such distinctions have their neural correlates in the differences in the way information is processed in the left and right hemispheres of the brain. The history of both language and science is the history of specificity, but on an organismal level, below the neural systems that support language and culture, the brain functions within broad contexts and emotionally maps general forms into which specific instances fall. ( Loss is the general form, a child losing a toy to another child, or the death of a spouse, are specifics.)

The relationship between specificityand metaphor is interesting as it has a bearing on certain laughter evoking events. The statements below are from the Metaphysics of Aristotle. .

The same attribute cannot belong and not belong to the same thing at the same time and in the same respect.

Not to have one meaning is to have no meaning.

It is impossible for anyone to believe the same thing to be and not to be.

By writing these words, Aristotle built a conceptual wall between the "civilized" world, in which precise thinking was favored, and that of the hunter-gatherers, where distinction dissolving and metaphorical thought prevailed.

I do not view the use of metaphor as a literary device so much as a facet of brain function. Before specificity and scientific analysis, that probed beneath the surface of things, classification functioned on a very superficial level. Form was paramount, and still is to young children, who will happily declare a large pink kangaroo to be a mouse. I believe, for the hominid brain, if two things looked the same they were the same and with the advent of language they were given the same name. In the Yaghan language of Patagonia, sleet has a name meaning fish scales, and even in western technological societies we cannot resist using metaphorical slang, as we do when we call diamonds "ice". This propensity of our brains to bracket together objects that are completely different, except for appearance, can cause conflict and the subsequent disinhibition of laughter.

One day, while I was sitting in our living room, my wife walked past with a handbag over her shoulder. On the bottom of the bag there were four prominent, rounded plastic studs, one at each corner. I burst into laughter, as the image immediately brought to mind a young heifer's udder. On another occasion I witnessed the behavior of a newscaster, on Australian television, who was unable to control his laughter because he could not get the vision of a cockerel out of his head when a picture of a boy with a bright red Mohican haircut appeared on the screen.

As we will see, in the final section of this essay, the processing of language - specifically the language of jokes - permeates all the main regions of the brain. This is not surprising as language represents our apprehension of the world encoded in sonic and symbolic form. What is more surprising is that the higher centers of the brain are not the only areas associated with the processing of language, but the much older, lower centers as well.

The true study of language, in the contexts of laughter and humor, is not the study of words and sentences but a study of their neural correlates. The laughter process existed before the joke and predetermined the form of the joke, and the cognitive and emotive correlates of words existed before words and initially determined the general form of language. There is no need for some inherent universal grammar to explain the form of language, as language, on a basic level, merely mirrors a simulative appreciation of reality. 

Only when we consider the first verbal utterances of our ancestors, and not the subsequent learning and use of those utterances, do we fully appreciate that the "meaning" of words are inherent in the cognitive and emotive systems of preverbal humans. On an organismal level, we apprehend our external and internal worlds in a similar manner to the apes. We have an appreciation of the sequences of events, objects, actions, the interplay of objects, the interplay of objects with ourselves, and our emotional responses to objects and events. Our ancestors associated particular utterances with objects and actions and the feelings that these evoked, and after doing so often enough, while perceiving aspects of the environment, the utterances would then elicit both their simulated reality and concomitant emotions even in their absence. Language evokes what could be viewed as a muted form of reality and all the areas of the brain respond to it in a similar, but muted, manner as they would to perceived reality. This means that even the older brain areas are active when we listen to language. Two such areas are the hippocampus and rhinal cortex. However, I do not believe that these areas take part in some form of translation of language but deal with memory and sequencing as they would if responding to an actual event.

The meaning of a word cannot be found in a dictionary, you can only find other words, which for you might have meaning. Something can be said to have meaning for an individual if there is a neural system in place ( whether innate or learned ) that can process the information it contains or set in train appropriate responses. "I", "we", "they", do not "understand" language; words merely evoke their cognitive and emotive correlates. The brains of children have to refine the cognitive and emotive correlates of a word to the degree that these closely match those of the preceding generation, before they can be said to have truly "understood" it.

Language evolved on the back of a highly developed cognitive system working in concert with an emotive system that interpreted information in terms of appropriate action. There is no reason to assume that the basic processes that triggered staccato vocalization in our preverbal, hominid ancestors are not the same processes that trigger laughter in modern Homo sapiens. If, as suggested, laughter is a form of displacement activity, that in the past was induced by any situation that involved motivational conflict, then it is highly probable that the specifics of jokes are also unimportant as far as the laughter process is concerned. In many cases it is not the language of the joke that is important but the way the mechanism of the joke evokes emotions and juxtapositions conflicting emotive subcontexts on a much lower, organismal level.

With a little rewording, almost all of the authoritative material ever published on the topic of humor can be fitted into a coherent theory. Without a unifying aspect operating below the level of language, writers have been free to highlight what they see as the most important characteristic of humor and put this forward as representing its true essence. The problem has been that the specificity that language imposes on our thought processes, and is required for intercourse in the cultural milieu, is not applicable at the deeper levels of neural processing. It would be grossly inefficient to have a neurophysiological system that reacted to specific situations, and on an organismal level our brains pay close attention to only two broad categories, situations that help and situations that harm; leading to three basic responses, approach, avoidance and freezing. Human lives are characterized by though, language and the complex social milieu that these cognitive and communicative phenomena have brought about. We tend to forget that although thought may guide our actions, it is action, not thought, that is essential to our survival. The complexity imposed by the specificity of language can be seen as being funneled down to the deep, emotive, organismal level, where everything is interpreted in terms of motivation and potential action.

We make a grave mistake when, for want of knowledge, precise definitions and an appropriate lexicon, we parade intellectual analyses as the neural processes behind certain phenomena. This, of course, is unavoidable, but we must be aware that the "story" of what we believe is taking place, couched in terms used in everyday cultural intercourse - outside coherent space/time frames and unrelated to other pertinent fields of enquiry - may be little more than an application of the presuppositions and biases required to validate existence within a cultural milieu. The cultural does not necessarily map onto the organismal.

Humor theories

when joke-telling humor is analyzed it becomes obvious that each of the three main humor theories focus on particular stages and aspects of the sequence of events that take place during a laughter evoking episode. To illustrate this, consider the steps that take pace during the telling of a joke:

a) An individual is moved to tell a joke.

The joke he/she tells has:

b) A theme

c) Story content

d) A mechanism (a format peculiar to jokes.)

As the presentation of the joke progresses:

e) The theme and content induce an emotional state in the listeners.

f) The joke mechanism produces a (irresolvable) conflict.

g) In response to the conflict the laughter process is disinhibited.

h) Listeners experience a feeling that they characterize as pleasure.

The aggression/superiority theory (Heyd 1982)(Gruner 1999) suggests that we laugh at the misfortune of others, or those who we consider beneath us in terms of power or social standing, and humorous situations are viewed in terms of aggression and competition. It focuses on the motivational (a), theme and content (b) (c), and emotional (e), aspects of a humorous event. Although aggressiveness may be the motivation for telling the joke, and also be included in the content, it is not directly responsible for the evocation of laughter. The superiority theory takes a socio-psychological approach to humor, which tells us very little about laughter and its functional relationship with humor. If we analyze the circumstances in which derision is used in laughter evoking events, we will see that the situation is much more complex than the superiority theory suggests. There are different ways to deride someone - with laughter accompanied words of derision, laughter at their misfortune and laughter evoked by disparaging jokes - all of which are quite different in the manner in which laughter is brought about. First of all we must make a distinction between Duchenne and non-Duchenne laughter in cases where laughter is used to deride someone or some group. It does not take young children long to realize that derision is particularly hurtful, but it should be noted that a young child's initial attempts at derision is accompanied by chanted, ha-ha-ha, laughter, and the laughter accompanying any disparaging statement made about a person by an adult is  probably of the non-Duchenne type.

An individual's laughter when witnessing someone's misfortune may be genuine laughter or non-Duchenne laughter, depending on the type of misfortune, the seriousness of the event and the relationship the witness has with the unfortunate individual. When people laugh on hearing a joke about a certain person or race they are not necessarily laughing at the person or group, they are laughing because the joke mechanism induces them to do so. The same joke is often used in different parts the world in an attempt to disparage enemies and those who are disliked by the locals. With the group or individual's name incorporated into the joke, the ensuing laughter offers momentary relief by inhibiting the emotional, often fearful, response to these people and so diminishing their psychological impact.  

In the case of genuine (Duchenne) laughter, in the context of what we have characterized as humorous events, I do not believe we laugh at, or laugh with, anyone, as the disinhibition of laughter is an involuntary response to conflict during event processing on a neurological level. The concepts of laughing with and at individuals have arisen due to a misunderstanding concerning the nature of laughter, especially its connection with aggression and superiority. To say we laugh at someone who has slipped over suggests the laughter is motivated in the same way as spitting at someone is motivated. What makes us laugh when friend, or foe, slips over is a simulation, in certain areas of the brain, of the physical and emotional aspects of the event which are in sharp contrast to one's own physical and emotional state.( The nature of empathy is explained in greater detail later in this essay.) The source of the laughter is the same in both cases, although we might laugh more heartily at a friend falling over (without any serious effects) than we would a foe, as the fear aspect would be greater for an individual we cared about. It is only on the post-laughter psychological level that a distinction is made. We apply the idea of laughing "with" an individual in the situation where a friend slips over simply because we associate laughter at another's discomfort with an antagonistic frame of mind, and this cannot be reconciled with our concepts of sympathy and friendship. The truth of the situation is conveyed when an apology such as, "I'm sorry, but I couldn't help laughing." is made. The erroneous concept of laughing "with" people, as characterized here, should not be confused with sharing jokes and joining in laughter with (in the company of) people.

Power and standing can be maintained by approval and respect, and only the fearful maintain power through aggression. Laughing at the less fortunate is not an act of the superior but of the frightened. We cannot inhibit the mental process we term empathy - it is an indispensable facet of comprehension - and because those people who laugh at the unfortunate cannot help putting themselves in the situation of those they belittle, the emotion behind their laughter is fear. These individuals have consciously distanced themselves from those they see as their inferiors; they do not sympathize with the less fortunate, but cannot escape the innate process of empathy, which places them in the very state they find repulsive.

The popular incongruity-resolution model (Kant 1790) (Attardo and Raskin 1991) attempts to describe how humorous material is processed in terms of linguistic/cognitive theory (b) (c) (d) (f), and although efforts have been made to reconcile the theory with neurological data (McCrone 2000), the basic concepts remain isolated from important biological considerations. The theory appears to be an intellectual extension of the common idea of "getting" jokes. The incongruity-resolution theorists believe humor is created by a multistage process in which an initial incongruity is created, and then some further information causes that incongruity to be resolved (Ritchie, 1999). It is possible that they are making no distinction between a post-delivery, conscious analysis of joke mechanisms and the neurological processing of jokes of which we are completely unaware. Even if the kind of analysis they suggest does take place during and immediately after the delivery of the joke, this does not lead to a convincing neurophysiological explanation of the evocation of laughter. The theory also falls down when considering many jokes of a sexual nature and does not take into consideration non-verbal laughter evoking situations. However, the idea of incongruity in general does suggest the inducement of incompatible neural entities, which gives us further insight into the nature of the laughter process.

The relief theory of humor is a "why" rather than a "how" theory, and basically views humor as been instrumental in the release  of what has been variously characterized as "psychic energy" (Freud 1916)(Spencer 1860) and painful emotions(e) (g) (h). Relief theories deal with the general effects of laughter inducing events and give little insight into the neurophysiological source of pleasure or the nature of the laughter process.

A displacement activity theory of laughter - in essence a theory of humor - combines aspects of the relief theory with the basic concepts behind incongruity theories, although, in line with the psychoneurological definition given in the introduction of this essay, displacement activities take place in response to irresolvable conflicts. A laughter theory of humor might be viewed as reductionist by those who take the broadest view of what constitutes humor, but it accommodates all the major theories and explains how they contribute to the processing of laughter evoking events.

Joke telling and other mirthful laughter evoking  events 

As I pointed out earlier in this essay, there is no possibility of finding an essence that unites all the phenomena we have termed "humor"; neither is there any sort of unity to be found in the contexts in which laughter takes place. There isn't even just one type of laughter, and to make the situation more complex, on a neurological level, there are a number of mechanisms acting through their own specific neural pathways that can lead to the disinhibition of laughter during both verbal and non-verbal events. All jokes do not have the same mechanism, and each type of mechanism dictates which brain areas are involved in the lead up to  the disinhibition of laughter. The same applies to non-verbal events, some having a mechanism that is close to that found in the majority of jokes, while others have a mechanism specific to non-verbal situations. We can view the disinhibition of laughter as a somewhat universal response to a variety of situations that entail irresolvable mental conflict or the redundancy of motivations.

Three neuropsychological phenomena that I see as being central to the disinhibition of laughter in verbal and non-verbal events are:

a) Inherent conflict.

b) Repression / suppression.

c) Empathy.

These are not necessarily mutually exclusive as empathy and suppression are also important in jokes that may have inherent conflict as the central mechanism, but have a content that deals with human nature and behavior.

The essence of the joke event is that it is devoid of immediate rational analysis. One does not advise the joke teller that lions can't talk when he starts his story with, "This lion said to an antelope...."; indeed, any discussion of a joke during and after telling is frowned upon. The enjoyment of all fictitious art is that we give ourselves up completely to it and suspend disbelief. Brevity is the soul of wit, because the less said the more imagined and felt. Explanation is kept to a minimum in jokes as it swings thought processes towards the rational and specific and away from the divergent processing on which the imagination feeds. Consider the following joke.

A concert pianist traveled to Africa in a bid to prove that music had the power to sooth the savage beast. With the help of native bearers, he set up his grand piano in a small clearing beside a river, and began to play. One by one, animals appeared, and soon he was surrounded by lions, giraffes, antelopes, warthogs and leopards, all sitting peacefully together swaying and tapping their feet. The pianist had just started to play a second piece when a crocodile splashed out of the river, grabbed the man, dragged him into the water, did a death roll and rammed him under a submerged log. An agitated lion ran over to the water's edge. "Why in heaven's name did you do that?" he asked. The crocodile cupped a foot to the back of his head and said, "Eh ?"

If we omit the last three lines and add, "because it was deaf", the joke is dead. The explanatory sentence inhibits the unconscious non-verbalized appreciation of the situation and the unconscious intercourse between different areas of the brain that are responding to the verbal input. It seems unlikely that during a process that demands a suspension of rational analysis part of the brain is doing a quick intellectual scan of the joke material as the incongruity-resolution theory suggests. In fact, as rational analysis developed late in the evolution of our cognitive systems, it is highly unlikely that it would occur before the lower levels of cognitive and emotive processing and the disinhibition of laughter had taken place.

The conflict in the crocodile joke is modal in nature. Most joke stories are fictitious, but only some are in fantasy mode. While listening to a fantasy joke, the brain can very easily stay in fantasy mode as long as the joke is describing action, but as soon as questions are asked, or explanations given, there is a tendency to slip into reality mode. The word "why", (for what reason), is particularly reality bound. If the joke had ended, "because it (the crocodile) was deaf", the processing of the joke would have quickly ceased, but by hinting at the answer to the question asked by the lion (the foot cupped at the back of the crocodile's head) the unconscious processing continues and the brain is induced to go through a type of processing typical of the rational/reality mode. In reality mode there is an appreciation of the fact that what has happened is typical crocodile behavior, and in fantasy mode there is an appreciation of "the fact" that the crocodile acted the way it did because it was deaf. The format of the joke produces a modal conflict by inducing the rational/reality mode of thought to justify the fantastic. 

The crocodile  joke highlights the difficulties the advent of language presented to the mammalian brain. It had to juggle and differentiate several presentations of language: the description of a reality perceived by the senses, a reported reality, a fictitious description of events that could be real (as in a novel) and a fictitious description of events that could not be real (as in a fantasy novel.), not to mention the reporting of events purported to have taken place that in reality did not, as when someone is mistaken or lies. It is little wonder then that fiction and reality often clash. A deliberate juxtapositioning of fiction and reality is at the heart of many laugher evoking events and, outside the field of humor, some children are unable to hold back laughter when they hear one of their number lie to an adult.

There are many jokes that produce conflict by the violation of natural laws or observable facts. A conjuror's tricks evoke laughter because he convinces his audience that he has performed the impossible and you only have to tell young children that a very large object is small to make them laugh. Although the two jokes below appear on the surface to be different, their effect depends on the violated of the same natural law.

An American tourist came across an unusual stall in an Irish market. He spotted a human skull, and asked the stall holder who it had belong to. The Irishman replied it was the skull of King Brian Boru himself. The tourist, being of Irish stock, bought the skull and took it back to the States. Some years later the American returned to Ireland and came across the same stall holder who was in the possession of a small human skull. The American asked whose skull it was. The Irishman replied "The skull of King Brian Boru himself." "But I purchased Brian Boru’s skull from you four years ago!", protested the man. "Yes, said the Irishman, "But this one is from when he was a boy".

An Australian and his faithful dog became lost in the outback, and after a week without food the man reluctantly decided he would have to sacrifice his lifelong companion. He built a fire and roasted the animal, piling up the bones as he devoured the meat. After he had finished he gazed pensively at the pile and said, " Blacky would have loved those bones".

Both these jokes depend on a violation of the space/time continuum. For the small skull to have been that of Brian Boru he must have been dead and alive at the same time, as he lived to produce a large skull. Without time travel, no one can be dead and alive at the same time, and for the Australian's dog to have appreciated those particular bones, this would have had to have being the case.

The most important aspect of many jokes is allusion - ideas and situations hinted at but not directly stated. It is thought that allusions are processed in the right brain, a fact that immediately suggests another form of modal conflict between the processing of information by the right and left hemispheres. However, it is the way allusions are registered that make them an important tool in the inducement of laughter. The listener's brain is not directly given all the facts of the joke situation verbally and is enticed to fill in the gaps. A falsity heard is immediately rejected if it is contrary to the listener's knowledge and accepted norms, and the effectiveness of an allusion lies in the fact that it is the listener's brain itself that generates the ideas and images and so a processed allusion has the weight of a contradictory conclusion.

Sexual Jokes      


It would be interesting, but fruitless, in the context of this essay, to list all the different types of jokes in respect of the modes and systems that are brought into conflict, but sexual jokes are a special case and deserve comment. We can only describe neurological events in "story" terms, as words are unable to convey the reality of processes that entail thousands of serial electromagnetic events taking place in various areas of the brain. We can intellectually analyze jokes and give explanations in terms of content and mechanism, and it is in the area of mechanisms that sexual jokes differ from other kinds of joke. Consider the following sexual joke.

Letter to the Agony Aunt of a women's magazine.

Dear Aunt Martha,

I have a problem. It concerns my husband, who demands I have sex with him at all times of the day, often at the most inappropriate moments. I have talked to him about his lack of consideration, but to no avail. Have you any advice on how I could break him of this distressing habit.

Thank you.
Bessie Brown.

PS. Please excuse the wobbly writing.

As with many sexual jokes, we can discern an allusive aspect that conjures up the sexual act, but having implanted an image in the reader's/listener's brain, with what does this conflict? Why do we laugh at sexual jokes? We cannot get anywhere by stopping at a link with embarrassment, as sexual embarrassment is unique to human beings, and we should ask the question: Why are we embarrassed by sex ? We can only answer this question by putting together, as best we can, an evolution of sexual behavior in primates, guided by the few clues history has left us.

The first two questions to be answered are: why does such a cerebral creature as man think about sex so often, and why does the human male have a sexual organ which is relatively much larger than the other apes ? Sex may well have been the central controlling factor in the organization of early hominid troops, and before language (verbal symbolism) genito-anal symbolism aided the coordination of the social group. The sexual control of stress in the Bonobo (pygmy chimp) (Stanford, C 1998), adds weight to the theory, but other than the large male penis, what evidence is there that genito-anal symbolism was involved in the control of early hominid behavior? The behavior of present day primates suggests that so-called perversions (homosexuality, coprophilia, sado-masochism, flashing etc.) have a long biological history. It is generally accepted that there is a large power component in the motivation to rape (McCabe and Wauchope 2005) and the genital displays of primates (Guthrie 1976) are mirrored by the flasher's vain attempt to demonstrate his dominance. Although we regard faeces, urine, saliva and even blood with distaste, some of the world's hunter-gatherers consider anything that comes from the body as having special powers. It is possible to view the naked, faeces smearing displays of powerless individuals in prison as a desperate last ditch expression of bodily power.

The life and sexual exploits of the Marquis de Sade (de Beauvoir 1951) suggest he was a man who had rediscovered in himself the seat of bodily power, and it is significant that he rejected the unemotional, abstract, concept based power of the church and state. Sado-masochistic practices also suggest a history of sexually based power within a changing hierarchical social structure. As the frontal lobes of hominids increased in size, and language evolved, the nature of communication and power shifted - genito-anal symbolism gave way to verbal symbolism and power gained an intellectual component.

Defecation, urination and sex are activities we have been unable to civilize and we never really get beyond our childhood assessment that love-making is the slapping together of smelly genitals. Yeats highlights the troubling state of being both human and animal in his poem Crazy Jane Talks With The Bishop, with the words "Love has pitched his mansion/ in the place of excrement." and Swift, in his Cassinus and Peter: A Tragical Elegy, has the young student, Cassinus, who has just found out his beloved is not the goddess he thought she was, exclaiming, "Nor wonder how I lost my wits; / Oh! Celia, Celia, Celia shits."

Sexual jokes, on the whole, lack the format to produce conflict directly. They depend very much on an allusive aspect, as demonstrated by the Dear Aunt Martha joke. Like most jokes they elicit the greatest volume of laughter when narrated rather than read. It is difficult to separate the reasons for this. A number of possibilities are: as laughter is a communicative phenomenon, it is more likely to take place in a group setting; being social creatures, our emotive systems are particularly active in group situations; some of the laughter is of the non-Duchenne type, resulting from the reluctance on the part of listeners to cause the narrator embarrassment; the relaxing atmosphere of the joke telling context facilitates the release of stress; and probably the most important aspect of narrating a sexual joke, the presence of other individuals when a particularly private aspect of human life is the center of attention. Children do not require embarrassing topics to be packaged as jokes to make them laugh and will often giggle at the mere mention of sex or bodily functions. There are sexual jokes in which there is no inherent conflict or allusive mechanism at all; none is required, as our very existence comprises a functional duality, and we vacillate between the organismal and the cultural - between the ape and the angel.

Below is one of the few sexual jokes I have found that does not depend on allusion, has no internal mechanism to cause conflict, and gives the full description of what is happening.

A woman finds that her sexuality is waning, and seeing an advert in a magazine for a pleasure boosting sex kit, she writes off for it. It duly arrives, and when she opens the box, she finds a list of instructions, two small bells and a tennis ball on a string. The instructions read : Place a bell on each nipple and suspend the tennis ball from your neck so it hangs at groin level - then, ring the bell, ring the bell, bounce the ball twice, ring the bell, ring...... If you find this works you might like to send off for our advanced kit. The woman practiced the movements, and finding that she and her husband are obtaining much more enjoyment from their sexual encounters, she sends off for the advanced kit. The new kit contained the same objects as the first one, but in addition a small blackboard and piece of chalk. The instructions read: Place a bell on each nipple and suspend the tennis ball from your neck so it hangs at groin level and put the piece of chalk between your buttocks. Ring the bell, ring the bell, bounce the ball twice, ring the bell, ring the bell, bounce the ball twice, then write 39 C(ents) on the blackboard !

One can almost feel the movement of the pelvis - the brain conjures up memories of such movements and you relive the experience of a very exciting and private moment in the presence of other individuals.
The fact that we laugh at sexual jokes strengthens my conviction that there is something deeper than a purely cultural opposition to an open acknowledgement of our animal nature, and I find it significant that even in the oldest human group, the !Kung San of Africa, the men only introduce the topic of sex with women and children in a joking manner. ( Janssen 2006)

Repression/suppression laughter    


Our mental life is characterized by conflict, and there is none more important than our attempts to maintain our cultural cognitive norms in the face of reality. In his book, The Denial of Death (176-178), Ernest Becker quotes Otto Rank, a contemporary of Freud.

"If man is the more normal, healthy and happy the more he can... successfully... repress, displace, deny, rationalise, dramatise himself and deceive others, then it follows that the suffering of the neurotic comes....from painful truth."

Adding later: "......the essence of normality is the refusal of reality."

A large number of suicides, and admissions to psychiatric hospitals, attest to the fact that people often lose faith in the emotively maintained, collective, cognitive norms that direct our lives as cultural beings. Man is a risky biological experiment as the complex brain that keeps the species in existence can also reject the cultural constructs that are so essential for relatively fear-free mental stability, turn on its own organism, and eliminate it. People do not necessarily commit suicide or become mentally ill because they are prone to thinking in a negative manner, but all thoughts that tend to depress militate against the attainment of good mental and physical health. The safeguards against destructive ways of thinking, that operate relatively successfully in most people, is repression and suppression.

If  someone bursts into laughter it is probably the result of neural activity being opposed or denied expression.  In the case of repression, and the more conscious form of denial, suppression, it is uncomfortable thoughts, painful memories and tabooed ideas that are being denied access to consciousness - an idea that parallels Freud's concepts concerning dream and joke function (Freud 1905). The fact that most sexual jokes have no inherent mechanism that involves cognitive and emotive conflict suggests they are processed in a different manner and along different pathways to the majority of jokes and should be placed within the repression/suppression category.

 We do not require jokes or staged situations to make us laugh; our most profound thoughts and anxieties can suddenly be disturbed by a simple everyday event forming the basis for a laughter inducing situation. I view the following story as an example of repression/supression laughter.

This real situation involves a burly, go-getting individual whose favorite saying was, "There are fish and leeches in the world, and God!, I hate being leeched!". He was observed at the breakfast table with a pencil in his hand on which a beetle was clambering. He tilted the pencil up and the beetle climbed to the top. He then turned the pencil upside-down, and the beetle turned and climbed to the top again. This was repeated many times and the individual laughed heartily throughout the exercise.

What should we make of this scene? There was more to it than the simplistic explanation that he was laughing at the stupidity of the beetle. Perhaps in a world in which we are all, to a great extent, controlled by external forces he unconsciously recognized a parallel between himself and the beetle. The repetitive nature of the beetle’s behavior suggested a further parallel. Most of us, at some time, have viewed our lives as a Sisyphean task, we seem to be going nowhere, other than in circles - getting up in the morning, going to work, going to bed, getting up in the morning......The beetle on the pencil had acted as a visual metaphor that evoked thoughts the man was reluctant to face. It would be dangerous to our mental stability if we constantly viewed life in a negative way, and the laughter process may reduce the occurrence of such thoughts entering consciousness, by preventing normally painful cognitions from evoking a negative emotional response.
It is important to our survival that we remember traumatic events and attempt to avoid the situations which led to their occurrence. It is also important that the memories of traumatic experiences do not enter consciousness so often they disrupt our lives by imposing a constant state of anxiety. During the rapid memory search which occurs when the brain is processing humorous material, or during events similar to the kind described above, past traumas may form part of the network of associations that is induced. It is possible that the unconscious inducement of a memory of a traumatic event, during a process that is inhibiting emotion, may, in the same way as crying, bleed the memory of some of its emotive impact and reduce the tendency for it to enter consciousness. The modern practice of encouraging patients to joke about their illnesses, and so lessen the impact of anxiety, is an excellent example of laughter aiding a return to a healthy mental equilibrium. In this case there is a conscious appreciation of the facts, but, as before, the thoughts, rather than being attended by a build up of emotion, are bound up in a process that is inhibiting it.

The title of Becker's book, The Denial of Death, brings to mind gallows humor. Some children cry when the think of death, and I have even met an adult who was prone to crying when the word death was spoken, but most people develop a non-emotional attitude toward the word as it is essential to repress our emotional response to death if we are to live relatively untroubled lives. Some individuals resort to religion to allay the anxiety engendered by thoughts of death and the perplexing question concerning the purposeof human life, but for many there is no such resolution. An example, and analysis, of a gallows humor joke is given below.

A man, who is being led out to the gallows, is wearing three coats and two scarves.

The warder asks, "Why do you have so much clothing on?"

To which the man replies, "I don't want to catch a cold."

We might say the impact of this joke lies in the fact that the man, who is about to be hanged, is communicating ideas inappropriate to the situation; but there are deeper existential considerations. The concept of purpose presupposes a future, and because the man had no meaningful future, his actions (putting on lots of clothing ) served no purpose. In a single episode the mind is confronted with two of the most troubling, and at times, depressing, aspects of human existence, and yet, as they are wrapped up in the context of a joke they are received with no negative emotional response.

It appears that to maintain stability in our cultural and mental lives restraints must be placed on aspects of both our animal and human natures. The restraints are of an emotive type, and in the case of human intellect, it is the emotive activity associated with an intense appreciation of the human condition that must be repressed. It is, therefore, little wonder that recent studies have shown that poets and writers are four times more likely than others to suffer from mental disorders, and, as a group, creative people are more vulnerable to depression and suicide (AFSP 2009). I believe that many individuals who have careers in the arts and entertainment, especially comedians, find their work both cathartic and therapeutic - an escape from an everyday existence in which we, of necessity, feign meaning and purpose. In the introduction to his book, The Picture of Dorian Grey, Wilde wrote "All art is quite useless", and for individuals who think and feel deeply, to passionately indulge in activities that are "quite useless" is one of the few antidotes to their existential angst. Philosophers deal with their existential anxieties in a different manner, neither by repression nor alleviation, but by accepting and expressing them.


Inherent conflict and empathy in non-verbal mirthful laughter evoking events    


 As I mentioned earlier, like jokes, not all non-verbal laughter evoking situations have the same mechanism. In the two examples of non-verbal events presented below, one has a conflict mechanism similar to that operating in the majority of verbal jokes, while the other depends on the more basic redundancy of fear response.

The close relationship between men and dogs is so conceptually and emotively embedded in the human psyche it has not only given rise to the assumption that a man chooses an animal most suited to his personality, but also spawned such sayings as "every man and his dog", and led to the absurd idea that men come to look like their canine companions. The latter observation is interesting as it demonstrates the application of a psychological bias that leads to an active searching for commonality between two entities that are so closely associated that they are seen as a unity. The sight of an exceptionally large man walking a Chihuahua, or a very small man walking a Great Dane, cannot help but induce laughter in observers. The sight of the man and his "inappropriate" dog places within a single picture a contrast that violates all the conceptions and emotions that make us view a man and his dog as a unity. Comparing this real, non-verbal, humorous event to the processing of jokes, we can view the dog and its owner as the conflicting aspects, induced by the joke mechanism, within in the picture of a single coherent storyline. Both the man/dog observation and the processing of many jokes result in the brain being presented with what has been termed conflict within unity.

Laughter can act as a useful modulator of the particular emotive states induced by both language and empathy. The advent of language, and the development of a highly sensitive, empathetic appreciation of the emotions of co-specifics, meant the mammalian brain was presented with a new phenomenon, emotions that were not directly evoked by a sensorially appreciated reality with which they were normally associated. Language evokes emotions in the absence of the objects and events it describes, and empathy induces emotions that are often not directly pertinent to an individual's emotive state or physical circumstances.
Empathy, in the context of humorous events, fits into the general category of non-actionable emotive states. At times we feel strong emotions that cannot be immediately and appropriately expressed because the causes may be distant in time or space, or we are subject to various physical or mental constraints. Emotive responses to reported events and thinking about the past or contemplating the future, and the inhibition of physical activity when such activity would be self injurious or socially unacceptable, are examples where emotive states are not appropriately actionable. 

In recent times - possibly due to the dissemination of psychological principles to those in service industries - in many peoples minds, the word "empathy" has become synonymous with, or at least inseparable from, the concept of sympathy.

In the 1987 edition of The Oxford Companion To The Mind, empathy is discussed without any reference to human relationships at all and emphasizes our ability to associate ourselves with the inanimate. By comparing ourselves with, and to, everything we encounter, empathy aids us in measuring our strengths and weaknesses and determining appropriate physical and mental responses to specific situations.Empathy is particularly important in human interactions as we cannot have sympathy without empathy, although it should be noted that sympathy is not an automatic result of an empathetic state of mind.

Empathy is important in the processing of laughter evoking situations as it is instrumental in the production of a changing complex of emotive responses as the event proceeds. When we observe another human being in certain extreme circumstances, or indulging in certain extreme behaviors, there is an empathetic induction of an emotive state that is not personally nor appropriately actionable. This empathetic appreciation of a situation is particularly essential in non-verbal humorous events such as clowning and slapstick. When we see a man slip on a banana skin our mirror and spindle neurons, which mediate our ability to empathize,(Schulte-Rüther 2007)  evoke an emotive state that is neither truly our own nor appropriately actionable. However, empathy may immediately give way to sympathy, which can give rise to appropriate action, such as helping the man to his feet and asking if he is hurt. Most people would not laugh if the fall was accompanied by a sickening thud as the man’s head hit the ground, as this would immediately induce a sympathetic state of mind. Laughter, for all but the sadistic, will only occur if the fall was perceived to have caused no serious harm.

A common explanation for laughter evoked by the sight of someone falling down is that we laugh because it has not happened to us. This is correct, but for the wrong reasons, as it is not a matter of being pleased that we have escaped an embarrassing or painful experience. The fact that the slipping on a banana skin has not happened to us means the empathetically simulated emotive states of startle, fear and pain, are at odds with the reality of our position in the situation, and when not overridden by sympathy, this emotive activity is inhibited as a result of the disinhibition of laughter.

Laughter, learning and childhood

Children enjoy being chased and tickled and will respond to a game of chase with someone they know well  by  bursting into laughter. However, a child who does not know the adult who has instigated  the chase may initially  burst into laughter  but then, (perhaps with the help of a few animal noises) suddenly begin to cry.

In nature, and outside the play situation, chasing and grabbing  are offensive actions and a fear response in the animal that is being chased  is essential to its survival. A child who continues to laugh throughout  a chase is able to keep in mind that the chase is merely a game and there is nothing to fear, even though his emotive centres are signalling that being chased is potentially dangerous. A child who initially laughs but then cries is overwhelmed by his emotional response and the laughter process is unable to inhibit activity in the area of the brain that mediates fear.

Young children find it hard to control their emotions as the connections between their prefrontal lobes and the limbic system are very weak. Perhaps, during our evolution, we came to utilise the ancient staccato vocalisation displacement activity as an relatively effective emotion control mechanism in young children.

Early childhood is the period of our lives in which we laugh the most. This is to be expected, as each day presents new and often challenging objects and  events. Babies form new minds almost from scratch, and their brains,  separating the useful from the useless and the harmful from the harmless, are in a constant state of ambivalence.

In most species, a displacement activity takes the form of disruptive  actions which physically preclude the normal activity taking place. The advantage of a vocal displacement activity, such as staccato vocalisation, is that it dampens down vacillation without preventing willed activity taking place. The laughter process facilitates exploration and learning in young children as they slowly adjust to the strange world they have entered. It is also possible that the laughter process is an important factor in the learning process itself.

It is essential for a children to learn quickly which things in the environment are harmful.  The greater the emotional impact of an experience the more likely it is to be held in the child’s memory. The greater the number of times an event is experienced by the child the more it is reinforced in the memory. An experience, which is potentially useful to a child’s development, could initially produce an adverse emotional response and end up being catalogued in the memory under "things to be avoided". Nervous laughter, brought about by remembering or reconfronting the experience, may bleed the emotional impact until it is so weak the experience can be reconsidered and its content utilised.

Additionally, and conversely, the laughter process may deny certain  experiences an emotional impact until they have been confronted many times, and only when they have proved to be valid and useful are they taken into memory.


A discussion of laughter would not be complete without an examination of the laughter inducing phenomenon we call tickling. If we cannot induce laughter by tickling ourselves it is obvious that laughter is a response to being touched by someone or something else. It would be quite disruptive if every time our hands accidentally brushed our bodies we drew back in fright and we have enough body maps in the brain (both in the cortex and cerebellum) to tell us when two parts of our body are in contact, and such contacts are ignored. We can also detect the difference between touching and being touched - the difference between moving part of our bodies on a foreign object and foreign objects moving on our bodies. Anything moving on our bodies is probably alive and thus a potential danger. One only has to have an insect running about under the bed sheets to know how quickly and emotively we react to being touched in a certain way.

Not everyone is ticklish, but those who are have little conscious control over their reaction to being tickled. Laughter induced by tickling is indicative of a conflict between our emotive system, which is sending out danger signals, and our appreciation that no threat to our organism exists.

The fact that being tickled on the bottom of the feet and the ribs elicits the most vigorous response suggests that these areas were particularly vulnerable in our primate ancestors. A rapid withdrawal of the foot from an unseen, sharp object, or an animal, on the ground would minimize damage or the effect of a sting or bite. The fear reaction of all primates to snakes, and their specific warning calls that signal a snake's presence, suggests a long history of primate predation by large snakes: some writers even view the relationship between primates and snakes as being of prime importance in our evolution (Isbell, L.2006). Primates are particularly vulnerable to large, night hunting, constrictor snakes, and as constrictors target the chest area to prevent their prey breathing, a rapid reflex response to being touched in this area would have been of significant survival value to our ape ancestors.

Significantly, the bottom of the feet, for most of the time, and the whole of the body on moonless nights, cannot be seen, and so sight is useless in immediately determining the source of the contact so that the appropriate action can be taken. In fact, any cognitive interference with the reflex response could prove to be
injurious or fatal.                                                        
When dealing with snake predators silently hunting in the dark a primate cannot resort to its senses of sight and hearing (especially if the primate is asleep) and it is probable that the system that immediately responds to particular types of touching functions independently of the other senses. The immediate response to tickling is a form of startle, an instantaneous escape reflex that gives rise to a secondary brain mediated fear response. This explains why, even though people can see what or who is tickling them - friend, stranger or machine - the reaction is the same. What an individual hears or sees during a bout of tickling cannot directly lead to the inhibition of the tickle response. However, the reality of the situation is registered, and the conflict between the tickle response and the cognitive grasp of the situation leads to the disinhibition of laughter. Displacement activities inhibit redundant emotive responses, but in the case of tickling there is a problem as every new movement of the fingers on a person's body rekindles the response and a continuous cycle of emotion (fear), disinhibition (of the laughter process) and inhibition (of fear), takes place.
The joke relies on the confliction of different combinations of emotions and cognitions.The emotions need not  be of a fearful nature, but telling jokes and tickling are united by a laughter response that results in a feeling of pleasure. 
( See NOTE at the end of this essay)

The neuropsychology and neurophysiology of stress and Laughter  
The reaction of a individuals to a specific joke is determined by genetic and environmental/cultural factors and their mental state at the time of telling . The material at which we laugh also changes with age; sexual jokes changing from toilet and genital humor, through sexual act humor, to jokes that incorporate sex and relationships. Young children enjoy word-play humor as they are still in the process of mastering language, but, for obvious reasons, cannot appreciate jokes that incorporate complex concepts. The effectiveness of a joke with inherent conflict, appropriate to a given listener, is a function of its mechanism and all the associations and attendant emotions the joke content has evoked. The joke mechanism creates the brain state that initiates the disinhibition of laughter - the volume and duration of which is dependent on the level of bodily arousal at the time of disinhibition. Berlyne believed that over-arousal was enough to cause laughter (Berlyne 1960), and Schachter and Wheeler found that pre-injections of epinephrine (which increases arousal) increased laughter when subjects watched a slapstick comedy film (Schachter, Wheeler 1962). Berlyne's theory was not validated by experiments carried out by Godkewitch (Martin 2007), but Schatcher's and Wheeler's experiment suggests that, although laughter may not be disinhibited purely due to high arousal, it does fuel laughter after its disinhibition.

The degree to which a joke can produce bodily arousal I have termed "emotive weight". Emotive weight possibly arises from the following sources:

1) Emotive activity directly engendered by the joke content. (jokes of a sexual, racial, violent and religious nature carry a high emotive weight.)

2) Emotive activity induced by associations and personal memories during the divergent phase of joke processing.

3) Emotive activity engendered directly by conflict.

4) Emotive activity extant at the time, which is independent of the joke processing.

When individuals are under the influence of chemicals, such as alcohol, nitrous oxide and recreational drugs, they may well laugh at the poorest of jokes, probably due to the fact that these chemicals lower the triggering threshold for laughter through their general disinhibitive effects. Many jokes with an acceptable mechanism may only give rise to a snort, possibly because a certain emotive weight is necessary before mirthful laughter takes place. The evocation of mirthful laughter, therefore, can be viewed as a function of both joke mechanism and emotive weight.

Displacement activities and laughter   

In the introduction to this essay, displacement activities were associated with the following:

a) Motivational ambivalence

b) Anticipation of change in activity

c) Actual change in activity

d) Internal conflict

The effects of displacement activities have already been described in the introduction of this essay as: lowering stress during motivational conflict and nullifying persistent emotive brain states when rapidly changing stimuli have rendered them redundant. Laughter not only parallels displacement activities in being an effective alleviator of stress but occurs in all the circumstances described above.

a) Motivational ambivalence                     Example: The laughter of a young child being tossed in the air.

b) Anticipation of change in activity.    Example: The immediate laughter when a well known comedian                                                                                                      appears on a stage.

c) Actual change in activity.                      Example: Laughter of schoolchildren let out of class for playtime.

d) Internal conflict.                                       Example: Laughing at jokes.

It should also be noted here that there are parallels between laughter and a phenomenon already accepted as a displacement activity, yawning. (Schniter 2001) The contagious aspect of laughter and yawning suggests that earlier in our evolutionary development both acted to coordinate and modulate group behavior.

The neurophysiological effects of a bout of laughter reveal it as an exaptation of a basic vocal, "fight or flight", displacement activity. Both a laughter inducing event and a "fight or flight" situation result in bodily arousal and a stimulation of the immune system, which is a normal response to both physical and psychological stress. During an episode of acute stress our bodies are readied to deal with any insult ensuing from the difficult circumstances in which we find ourselves - this includes the activation and release of large numbers of immune cells into the blood. Laughter has been reported to increase the numbers of natural killer and activated T cells, along with an increase in concentrations of immunoglobulins and gama interferon which help to fight infection and activate immune cells.(Berk and Tan 1996) In an earlier paper Berk reports a decrease in the blood levels of epinephrine (often called the fight or flight hormone) as a result of mirthful laughter, although in the majority of experiments dealing with the neurophysiological effects of laughter an increase in stress hormones has been detected. Indeed, the reported levels of cytotoxic cells, neuroimmunologically active molecules and stress hormones in the blood vary so much from experiment to experiment that no specific conclusions can be made that are pertinent to the present thesis. Although we will have to wait until the inherent flaws in the various approaches are addressed, we can come to a general conclusion: however muted and variable the neurophysiological effects of laughter are, they do parallel those typical of a response to a stressful event.

Why should the telling of a joke, often in a relaxed atmosphere, lead to an immune response typical of a stress situation? The answer is that the processing conflict imposed by the joke mechanism mimics the motivational conflict typical of a "fight or flight" situation and leads to a similar, but muted, response.    

The relationship between the nervous and immune systems is complex, as is the relationship between the immune system and neurotransmitters (Segerstrom and Miller 2004). The immune system can be directly stimulated by sympathetic nerve fibers from the brain as well as indirectly through stress hormones, and endogenous opioids can stimulate or inhibit the immune system, depending on their levels in the blood.  (Jonsdottir 2000)  

Beta-endorphin, often associated with the evocation of laughter, is to be found in the neurons of both the central and peripheral nervous system and in the blood and lymphatic system. Some leukocytes can produce beta-endorphin, secrete beta-endorphin and take up beta-endorphin from the blood (Csaba et al 2002) , and to further complicate the situation, at any given time, there is no correlation between the levels of endorphin in the circulatory system and those in the brain as water soluble peptides cannot pass through the blood-brain barrier. It is this complexity that has made the endorphin/laughter connection so controversial. Although the production of beta- endorphin during a laughter evoking episode has been reported in many articles in the popular press, no scientific research has confirmed that this is the case. A similar controversy surrounded the endorphin induced "runner's high" when the exposition of the blood-brain barrier findings brought into question the assumed connection between endorphin levels in the blood and the elevation of mood after strenuous exercise. However, recent advances in imaging techniques have enabled researchers to demonstrate an increase in opioids in the brain after strenuous exercise (Boecker et al 2008), and there is no reason to dismiss the idea that a similar increase in the brain's opioids will be found after a laughter evoking event.

The suggested neurophysiological responses of a hearer of a joke narration are:

1) Emotive activity is engendered directly by the joke content and by the inducement of associations and personal memories.

2) The format of the joke (the joke mechanism) produces a processing conflict.

3) The processing of the joke is halted and the emotive activity sustaining the conflict is inhibited as a result  of, 0r during, the disinhibition of laughter.

4) A feeling of relaxed pleasure is experienced.

If the nature of pleasure is, as I formally stated: the conscious appreciation of a change in brain state brought about by the fulfillment or inhibition of the motivations that sustain the neurohormonal correlates of stress, then the concept of "reward" in the case of laughter is redundant and the possibility is that the opioid which is assumed to directly give rise to a feeling of pleasure is in fact merely closing down emotive activity once a desired goal is reached or inhibited.                                                                                                                                                                                                       The processing of a humorous event, acting as a mild stressor, explains why the event elicits a muted immune response, but what accounts for the reported lowering of stress after laughter. A possible answer is that the second stage of the laughter process not only inhibits the emotive activity induced by the humorous event but also facilitates the inhibition of other emotive activity extant at the time. As stress can be viewed as an emotion driven preparedness for action, then the inhibition of emotive brain activity, as the result of the disinhibition of laughter, would account for the lowering of overall stress, at least for a short period after the humorous event.     

The neural correlates of laughter and laughter evoking events       

The number of brain areas that have been associated mirthful laughter evoking events is large. They include the anterior cingular gyrus, the dorsolateral and medial ventral prefrontal cortex and orbitofrontal cortex, insular cortex, amygdala, basal ganglia, nucleus accumbens of the ventral striatopallidium, as well as the hypothalamus, the hippocampus, thalamus, the periaqueductal gray matter, the cerebellum, medulla and pons. (Biraben et al, 1999) (Heyd and Dolan, 2001) (Parvizi et al, 2001) (Wild et al, 2003).

The functions and connectivity relationships of some of the brain areas listed above are suggestive in explaining where and how the major mechanisms of laughter disinhibition (inherent conflict, suppression/repression and empathy) take place.

Inherent conflict     

 All events, whether verbal or non-verbal, laughter evoking, or not, are initially processed in the same manner. On the subcortical level, the amygdala is involved in the emotional responses to sensory events whereas the hippocampus, which is important in learning and memory, is more concerned with the spatiotemporal aspects.

The functions of these subcortical bodies are reflected in the areas in the prefrontal lobes to which they project. The amygdala has robust connections with the orbitofrontal area, which is concerned with the emotional aspects of an event, and the hippocampus projects to the dorsolateral prefrontal cortex which is responsible for working memory and planning, and so is concerned with the informational content of the event.
There are strong connections between the dorsolateral prefrontal cortex and the orbitofrontal area, and the lateral orbitofrontal cortex is thought to be where the integration of cognition and emotion takes place.(Gray et al 2002) During the processing of jokes that rely on an inherent conflict mechanism the punch lines may present these brain areas with two conflicting interpretations of the joke story, along with two concomitant conflicting emotional contexts, which make normal and meaningful processing impossible.
The relative emotional and cognitive contributions to inherent conflict vary. In the Brian Boru joke, cited earlier, there is a cognitive conflict (a violation of the space/time continuum) and so the contribution of the hippocampus and dorsolateral prefrontal cortex would be high. The joke below relies on a conflict of emotions which would bring a higher degree of involvement of the amygdala and orbitofrontal area.

Mick and Paddy, two I.R.A. men, are waiting down a dark alleyway hoping to ambush a member of the Ulster Constabulary and shoot off his knee-caps. He normally finishes his shift at ten, and passes the alley about ten fifteen. He hasn’t appeared by ten forty five and Paddy turns to Mick and says, "He should be here by now. I hope nothing’s happened to him."


The functions and connections of the ventromedial prefrontal, orbitofrontal, insular and cingulate cortices suggest that these areas represent the substrates responsible for the control of denial, disturbing thoughts, painful memories and tabooed ideas. An inherent conflict laughter evoking event might activate these brain areas but its essential mechanism is a neurological processing of conflict. Repression/suppression mechanisms of laughter disinhibition are essentially psychological in nature. The areas of the brain that are manipulated in this case are those that are responsible for self awareness: the self in relation to existence as a whole, the self in relation to other human beings, and the self in relation to society and society's mores, as well as an appreciation of the bodily self.

The medial prefrontal cortex, the anterior insular and the anterior cingulate cortex are all activated during self reflection (Modinos et al 2009) and all the above mentioned cortices are involved in the learning and/or control of moral behavior. Alicja Lerner's work (Lerner et al, 2008) suggests that unwanted memories, impulses,behaviors and emotions are suppressed by processes that involve the anterior cingulate, orbitofrontal cortex, insula and the prefrontal cortices.

It is interesting to note here that mildly offensive material used during joke telling enhances the activity in the ventral medial prefrontal cortex and elicits laughter (or at least is judged to be "funny") whereas in individuals who find the joke material extremely offensive there is a relative decrease in ventral medial prefrontal activity, an increase in hippocampal activation, and the joke is considered as not "funny". (Goel, Dolan, 2007)
There is a parallel here with the basic laughter response where the degree of fear engendered by an event can determine whether an individual laughs or not. During events that evoke a high degree of fear there is no opposition to its expression, but low degrees of fear can be opposed and so often result in a disinhibition of laughter. In many sensitive, religious and prudish individuals there is both intellectual (cognitive) and emotional opposition to particular joke material and this precludes the disinhibition of laughter. There has to be a certain degree of ambivalence for a joke to elicit laughter and in these individuals this is lacking. For those who laugh at jokes other people find offensive there is an intellectual acceptance of the material but also a degree of learned social/emotional opposition.
Enhanced activity in the ventromedial prefrontal cortex signals attentional processing of  the joke content; a relative decrease of activity signals opposition  to the  the joke content.  
Most sexual jokes rely on allusion which induces the listener's brain to imagine sexual activities independent of the story content. In those who have an intellectual acceptance of sexual material and a muted social-emotional opposition to it, the laughter response is automatic. In those who find sexual jokes offensive, the automatic response to joke processing is blocked  by an attitudinal response that works to inhibit sexual thoughts.
Abnormalities in the size and form of the hippocampus in antisocial individuals (Raine and Yang ,2006) suggests that the certain activity in hippocampus is in some way instrumental in the application of learned responses to the violation of social norms. I believe the ventromedial prefrontal activation is low in individuals who find the sexual content of jokes highly offensive because the responses that are reflected in hippocampal activity inhibit the contemplation of sexual activities and so there is nothing to oppose.
                                                                                                                                                                                                                       Our ability to empathize is mediated by unique groups of cells in various areas of the cerebrum. There appears to be two types of cell which might mediate different aspects of empathy, namely the mirror and spindle neurons. The mirror neurons have been located in the inferior parietal lobe and the lower precentral gyrus (ventral premotor cortex) of primates. There is no direct evidence demonstrating their existence in humans but brain activity consistent with mirror neurons has been registered in the same areas of the human cerebrum. The spindle neurons, on the other hand, have been found in the insula and anterior cingulate cortex of apes and humans and also in the brains of whales and elephants. Some writers (Decety and Moriguchi 2007) believe that the spindle neurons in the cingulate region of the cerebrum are involved in "judging the emotion in another person's gaze, to detection of intention in simple dynamic animations, attribution of intention to cartoons characters, story comprehension, detection of social transgression, and appreciation of humor."

In an experiment concerned with bodily ownership and anxiety (Ehrsson et al, 2007) it was found that there was a correlation between the activity in the both the ventral premotor cortex and the left intraparietal cortex and the insula, which suggests that the mirror neurons, in at least one area, are in contact with a region containing spindle neurons. It is possible that the mirror neurons are responsible for the mapping of the movements of someone slipping over whereas the emotional response, and an appreciation of the fact that the induced emotions are not directly associated with one's own physical and mental state, take place in the  insula/cingulate region, resulting in a lowering of activity in the amygdala.

As well as the "slipping on a banana skin" response, empathy allows us to respond emotionally to reported or read fictional events such as jokes, setting up a state of arousal that fuels laughter once the joke mechanism has led to its disinhibition.  

The nucleus accumbens and cingulate cortex: the processing of laughter evoking events    


Activation of corticomesolimbic dopamine system, in particular the nucleus accumbens, has been implicated in the hedonistic (reward) effect of laughter evoking events. .(Mobbs 2003) However, it is more probable that the activity within the corticomesolimbic dopamine system is associated with the processing of the event prior to the disinhibition of laughter. In experiments unconnected with humor, researchers have found what they believe to be hedonistic "hotspots" in the nucleus accumbens shell but identify them as relying on opioid rather than dopamine stimulation.(Berridge, K and Kringlelbach 2008) This and other experiments conducted by Berridge and his coworkers suggest that dopamine is not the "reward" transmitter and Phillips (Phillips A G et al 2008) points out that enhanced dopamine release is also linked to error detection, responses to novel stimuli and incentive motivation. In addition to this, it has been demonstrated that an active corticomesolimbic dopamine system is essential for a drinking displacement activity to take place in rats. (Robbins and Koob 1980)

Displacement behaviors have been linked to lower dopamine levels in the prefrontal cortex and the attenuation of the physiological indices of stress in rats (Berridge, C. et al 1999) and experiments performed by Jackson and Moghaddam (2001) suggest that the absence of prefrontal control, due to low dopamine levels in this region, may result in aberrant behaviors and response perseveration (persistence/repetition) after stimulus termination. During the processing of an event the inputs from the nucleus accumbens and the hippocampus and amygdala are sustained until the prefrontal processing is concluded. This cessation may represent the acceptance of the cognitive and emotional aspects of the event as being meaningful and their integration into the brain's pool of experience and knowledge, or result in an appropriate physical response. If the prefrontal cortex cannot fully process the inputs from the subcortical level and bring processing of an event to a conclusion because of conflict, then the inputs from the subcortical regions, such as the amygdala, cannot immediately be shut down.

The anterior cingulate cortex appears to be the hub of executive function, receiving projections from all the prefrontal areas and the insula, as well as many other regions of the brain. It obviously plays a greater role in the overall processing of laughter evoking events than is outlined here, but it is its functions of conflict detection and behavior selection that are important in the final stage of laughter event processing, the disinhibition of laughter itself.

The anterior cingulate cortex is considered to be the region that detects response conflicts in the areas to which it is connected. (Carter and van Veen 2007)  ( Yeung et al 2004) I hypothesize that irresolvable conflicts in the prefrontal areas, the suppressive conflict stalemate and self/non-self contradiction during processing within the prefrontal cortex and cingulate/insula regions, are shut down by the inhibition of the limbic inputs that sustain them.
The following figure shows the different pathways by which Duchenne and non-Duchenne laughter are released. I view Duchenne laughter as being disinhibited in the same manner as that of primate calls - the processs originating in the precollosal cingulate cortex. 
If we consider the most basic of laughter evoking events - the realization that a situation, initially seen as dangerous, is in fact benign -the figure shows how the process by which laughter is disinhibited can also result in the inhibition of the fear evoking activity in the amygdala. There is a periaqueductal gray matter opioid receptor pathway that is instrumental in the extinction of the freeze fear response arising from activity in the amygdala (McNally et al 2004).  McNally concludes that, "Taken together with our previous findings, we suggest that, during fear conditioning, activation of vlPAG opioid receptors contributes to detection of the discrepancy between the actual and expected outcome of the conditioning trial. vlPAG opioid receptors regulate the learning that accrues to the conditioned stimulus and other stimuli present on a trial because they instantiate an associative error correction process influencing unconditioned stimulus information reaching the site of CS-US [conditioned stimulus - unconditioned stimulus] convergence in the amygdala."

Although there is no evidence that this pathway and the disinhibition of laughter pathway are the same,  the situation is suggestive in explaining the relationship between the disinhibition of laughter and the inhibition of fear.
 It can be seen that the experience of what is termed "mirth", not registered during non-Duchenne laughter, is the result of midbrain and limbic interactions, and if activity in the periaqueductal gray matter is responsible for the inhibition of amygdalal output, then the feeling of mirth, in this case, can be viewed as the conscious appreciation of the arousal effects of fear in its absence.
The relationship between laughter evoking events and their physiological effects 

This essay is not concerned with the neurophysiological effects of laughter evoking events in terms of their possible application in the field of medicine. However, the analysis of blood profiles, coupled with imaging techniques, can aid in unraveling the complex relationships and mechanisms that comprise the humorous event. In most of the experiments that attempt to elucidate the neurophysiological effects of laughter there has been little thought given to the evoking stimuli which possibly indicates that some researchers believe laughter itself is responsible for the effects and not the stimuli. For the results of an experiments concerning a laughter evoking event to be of any value (at least to the humor theorist) a standardization of the stimulus is just as important as having as homogeneous a subject cohort as possible.

I have postulated that there are possibly four sources of "emotive weight" - the emotive responses evoked during a joke telling event - and each source will have some effect on the blood profile. In addition, I have outlined what I view as three major mechanisms responsible for the disinhibition of laughter. This situation has the potential to give rise to a complex variety of psychoneurological and neurophysiological responses which may explain why, in addition to the questionable procedures (outlined in Ron Berk's humorous critique(2004)), experimental blood profiles have exhibited such variation. Different types of mirthful laughter evoking situations will activate different areas of the brain, which in turn will add their own particular neuorphysiological responses to the mix
The physical act of laughter does not account for the majority of the physiological responses that are reflected in the cellular and molecular changes in the composition of the blood. It is the neuropsychological and neurophysiological responses to the laughter evoking event that cause such changes. Laughter shuts down the responses set in train by the event, although, in doing so, it could add a subset of changes specific to the disinhibition of displacement behaviors.
I believe that, for the laughter/humor theorist, the only meaningful results that could be obtained from a study of the effects of mirthful laughter evoking events would be from a series of experiments in which the same, large subject cohort was presented, on separate occasions, with different types of events. These might include: listening to a punning comedian, sexual joking and a slapstick clown act - a collection that covers the three phenomena that I consider to be central to the disinhibition of laughter: inherent conflict, repression/suppression and empathy. Blood profiles, in combination with imaging results, obtained from the studies of different stimuli would give a much more comprehensive picture of what is taking place during the processing of laughter evoking situations.
Neurology is one of the most complex of our objective fields of study and so it is little wonder that the body of speculation greatly outweighs the body of fact concerning brain function. What I have written above is a simplistic "best guess", and until the technological tools used to determine the physical and physiological functioning of the brain are greatly refined, neurology will remain, in many areas, a "best guess" science.
 In a paper that attempts to determine the differences in the neurological areas activated by different modes of presentation -sight gags and verbal humor - (Watson et al 2007) some of the results are interpreted in terms of the incongruity resolved humor theory and the mesolimbic dopamine reward theory. Berridge's work seriously questions the mesolimbic dopamine "reward" theory and, as far as the incongruity resolved theory is concerned, I view it as having taken the conceptional route from the common, and I believe, erroneous, idea of "getting" jokes, and by an intellectual extension, to psycholinguistical concepts that are then applied on a neurological level. There can be no advancement without speculation, but neurology suffers greatly from the fact that the results of experiments are sometimes interpreted in terms of the "best guesses" from other fields of study in a top-down manner, not to mention the biasing effect of words and ideas taken straight from the cultural milieu.



                                                                                                                                                                  The difficulties experienced by researchers in explaining the phenomena of humor and laughter have not only arisen from flaws inherent in these studies themselves but, I believe, errors in accepted neuropsychological theory.

Humor theorists often begin their research with an acceptance of the idea that the basic acts of laughing and crying are indicative of positive and negative emotional states respectively, rather than, as I suggest, responses to the blocking or redundancy of fearful and aggressive states. In some cases, this has lead to the assumption that laughter is a subsequential rather than a consequential response - a response to a pleasure inducing outcome rather than a response elicited during the processing of the laughter evoking event.

There is still some acceptance of the ideas that dopamine within the corticomesolimbic dopamine system is responsible for the “reward” and pleasure aspects of the response to what we have termed “humor“. Berridge’s work suggests that although there are hedonistic hot spots in at least one component of the dopamine system, the nucleus accumbens shell, these are stimulated by opioids and not dopamine .The nucleus accumbens is viewed as the gate between motivational and motor systems but the possible link between opioid activity in this region, laughter and the inhibition of behaviors has not been investigated.
Ist man. “Why are you banging your head against the wall.”

2nd man. “It’s lovely when I stop.”

My most contentious assertion is that pain is absolute in nature whereas pleasure is relative. I am not completely alone in this view as the 19th century German philosopher Schopenhauer wrote in Counsels and maxims:

....pleasure is only the negation of pain, and [that] pain is the positive element in life.”

And after a study at the Massachusetts General Hospital (Becerra et al 2001) demonstrated that the brain's reward areas also activated by pain, Hans Breiter, a radiologist at the hospital, said:

"This study supports the concept that there is a continuum between reward and aversion. It would appear that the philosophers Spinoza and Bentham, who proposed that pleasure and pain were part of the same spectrum, were right."

Berridge views the opiod activty in the nucleus accumbens as resulting in positive pleasure.  (Berridge and Kringelbach 2008) However, I see no reason to reject the idea that the brain can interpret the relief from stress (mental pain) as being pleasurable. Mood is an interplay between arousal and stress, and as jokes are known to increase basic arousal and decrease stress, then I can see no objection to assigning the feeling we call pleasure, derived from jokes and other laugher evoking situations, as arising from these two sources.

In addition to what I see as the application of erroneous neuropsychological theory, my objections to the three main humor theories are based on their limited application to all forms of humorous (mirthful laugher evoking) events and types of laughter, the relegation of emotional aspects to a secondary level, and the application of what I believe to be erroneous assumptions, that we can laugh “at” people and “get” jokes.

By applying the word “humor”, with its many differing cultural applications, to their field of study, researchers immediately painted themselves into a corner. The fact that the term “humor” cannot be defined to a level of scientific usage - and the reliance of some researchers on their intuition (we know what humor is when we come across it) - has led to some writers using such nonsensical phrases as, “we experience humor,“ and ,“humor takes place“. The words “humor”, “funny” - and although I have used them in this essay - also “wanting”, “liking” and “reward“, should never cross the cultural/ brain barrier and be applied directly to neurological processing.

The idea that we can laugh “at” people is the foundation of the superiority/aggressive theory of humor. Only the chanted, Ha..Ha..Ha. of children and the more convincing non-Duchenne derisive laughter of adults come anywhere near to laughing at someone. The telling of a racist joke may be motivated by fear and hatred, but the laughter itself is not consciously motivated, but automatic. I tearfully bristle at the injustices and cruelty the Jews endured in the second word war, but I still laughed when I heard the joke: Israel is bankrupt. Germany just sent them the gas bill. I was not laughing with or at, or in any way denigrating, the Jewish people. The ludicrous suggestion that they should pay for their own mass murder and the juxtapositioning of a mundane event, the reception of a utilities bill, and the mind crushing enormity of the holocaust, elicited enough conflict to induce the disinhibition of laughter. However, it was a degree of distancing of the self from the historical event that allowed the disinhibition to take place.I view the superiority theory of humor as a flawed, “why”, sociobehavioral theory and a non-starter as far as a coherent explanation of laughter and laughter evoking events are concerned.

I view the incongruity resolved theory as extension of the common and erroneous idea of “getting” jokes. A strict interpretation of the theory is losing ground even amongst the linguists who favor this linguistic/cognitive explanation. In 2005, on an online humor discussion group, the linguist, Salvatore Attardo stated:

A caveat, though: it is important to remember that incongruities in a joke can be fully resolved, partially so, or not at all.”

Although I agree that conflict is at the heart of laughter evoking events, I believe it is irresolvable conflict that induces laughter. A strict linguistic/cognitive theory of “humor” separates the processing of verbal, laughter evoking events and laughter, parading a reasoned, post-joke analysis of the mechanism and an unsubstantiated “getting” of the joke as the actual neurological processing , calling it “resolution”. The theory takes little note of the emotional aspects of humorous event processing, and ignores the fact that although the cognitive conflicts may be understood (resolved, as the theory’s proponents see it), the conflicting emotional contexts cannot be reconciled.    

I view the incongruity resolved theory as being correct in distinguishing the basic mechanism of jokes, but it falsely applies the concept of resolution, does not give an adequate explanation of the evocation of laughter or the feeling of pleasure and, although laughing is an ancient behavior, gives no insight into its biological nature.

The relief theory of humor is another “why” theory, but this time explanation is on a psychophysiological level. Although the best known proponents of the theory, Freud and Spencer, did not have the knowledge to express their ideas in language acceptable to scientists today, they did introduce an emotional aspect into the mix. The incongruity theorists exposed the mechanism of a laughter evoking episode but neglected its emotional aspects; the relief theorists introduced an emotional component but failed to elucidate a convincing mechanism.

As I point out in the main body of this essay, the three main humor theories focus on particular stages and aspects of the sequence of events that take place during a laughter evoking episode. No single theory encompasses the diverse aspects of laughter and laughter evoking events and none address their biological underpinnings or explain their physiological effects, which is essential for a full understanding of these phenomena.

The idea that a displacement behavior is at the heart of both laughter and humorous events is a bottom-up hypothesis and so initially avoids the stagnating effects of competing humor theories. It is the only hypothesis that I see as being able to give a meaningful explanation of the relationship that exists between laughter and the processing of events that cause its elicitation, doing away with vague explanations such as the idea that we laugh with pleasure when we have resolved incongruities.

The three main humor theories also suffer from the fact that they are not anchored within meaningful space-time frames. A theory that does not address the “where”, “when” and “how” - in other words, a theory that does not allow a phenomenon to be temporally and physically mapped (in the short term neurologically and the long term phylogenetically) must remain vague and, for the most part, will not lend itself to experimentation.

I have spent some time in this essay musing on the nature of language. I believe this was important, not only because many mirthful laughter eliciting events are verbal in nature, but to highlight the fact that although the laughter displacement activity is disinhibited during the processing of language, in the rest of the vertebrates displacement activities are associated with action rather than thought. However, this is not so surprising when it is realized that language does not depend on evolutionary new, "clip on" systems but is rooted in the oldest systems that mediate motivation and action. Language sits on the top of a series of exapations, from the reorganization of reactive systems in the development of cognition to the exaptation of primate vocalization in the service of speech. Language probably shares many systems that evolved to manage our dealings with the physical world. William Calvin, (Calvin 1993) proposes that the sequencing of movements (as in throwing) and the sequencing within language are mediated by the same systems and it is possible that the hippocampus is not only important to the physical act of navigation but also "navigates" the form and content of written and spoken language. (O’Keefe and Nadel 1978)

If a piece of writing can be seen as a maze, having an entry point, entailing being understood, and once understood, resulting in an exiting, then the processing of a joke can be viewed as the entering and navigation of a exitless maze, and the  disinhibition of laughter a successful exiting, not by completion, but by jumping over an outer hedge.                                                    

Laughter appears to display all the characteristics of a displacement activity, but further studies are required to determine if the superficial parallels are mirrored in a common neurophysiological profile. With enough money and time, a whole raft of studies could be undertaken. The validity of separating mirthful laughter evoking events into the mechanism groupings of inherent conflict, repression/suppression and empathy could be tested. The results of imaging and blood profiling tests performed during laughter evoking events utilizing a single mechanism and others that utilize a combination of mechanisms might be compared. This could entail basic “polite” puns and puns with some sexual content, such as : What is the difference between a clock maker and a warder? One sells watches, and the other ...., and: What is the difference between a street vender and a Dachshund? One bawls out his wares on the road, and the other....


I believe that there is little doubt that the basic, organismal laughter is a response to fear. The line of apes that gave rise to Homo seem to have a quite complex geographical history which included times when their environment was warm and supported large constrictor snakes. I believe the basic response to being caught by a constrictor snake (rapid breathing) has survived in the chimp, the the ancestors of which were the second great ape to migrate south, following the gorilla's ancestor.    

The ape that gave rise to one group of Homos (having dispersed throughout Eurasia) probably spent some time in a northern temperate environment, and then in the southern grasslands of Europe, now free of the threat of large snake attacks. This is probably when the basic laughter response became voiced and acted as a false alarm signal and also as a bonding play activity.

There is a theory, one to which I subscribe, that the extant great apes began their evolution in Europe. There are very few fossil remains of great apes in Africa - only a few teeth which are thought to represent a species of gorilla and a species chimpanzee - but during the Miocene epoch (23.3-5.2 Ma) there were a large number of apes in Eurasia. A cooling climate may have caused the early European members of the great ape family (Hominidae) to migrate south into the warmer climes of Africa.   

 Humans differ from other apes in having a fat layer just below the skin and can conserve heat through a countercurrent blood flow system in their extremities. Other than the aquatic ape theory, there is no explanation why such adaptations should have evolved in Africa. This leads to the possibility that the ape that gave rise to humans was the last to enter Africa after existing alone for some time in temperate conditions. Further pieces of evidence that point to an "into Africa" scenario is the fact that a fossil ape from Hungary, Rudapithecus, has large frontal sinuses (absent in Asian orangutans), brow ridges and a downwardly bent face, typical of extant African apes.                                                                                                                              

 The idea that laughter is an expression of positive valence ignores the fact that the most primitive form of laughter is exhibited during tickling. It is primitive in that it is found in our ape relatives and is also a reflexive response. Reflex responses are not under conscious control and are usually associated with survival behaviours. This means that the response of our ape ancestors to being touched in a certain manner (similar to tickling) was extremely rapid and independent of the other senses and cognitive inputs that might have slowed down escape strategies. Such split second, reflex responses would have been of great survival value during ambush attacks and night time attacks by tree climbing predators.                                                                                                                            

 The laughter patterns of humans and chimpanzees are the most rhythmic and have the shortest inter-call intervals of all the great ape species. However, whereas human laughter is voiced, chimpanzee laughter takes on the form of rapid panting. Why was the rapid panting of chimpanzees, and presumably the common ancestor of chimpanzees and humans, so important that it had to be encoded in their DNA?

Primates have a very long history of snake predation. This is inferred from the facts that monkeys have a specific alarm call for snakes and experiments have demonstrated a genetically based fear of snakes in monkey species. In 2011, German and Czechoslovakian researchers, working in Southern Germany, found 15 million year old fossilized snake vertebrae, which they calculated to be from a three and a half metre python. It is hardly likely they chanced upon the largest specimen of the largest constrictor species that existed in Europe at that time, and this find indicates the possibility of the existence of constrictor snakes capable of swallowing a medium sized primate. Constrictor snakes tighten their coils every time the prey animal breathes in, and it is possible that rapid panting disrupted this constriction process enough to allow the prey animal to wriggle  free.  

 During the late Miocene cooling of Europe, large constrictor snakes either died out or migrated to warmer climates, and in some areas savannah-like grassland developed. This left our hominin ancestor with a stereotypic behaviour which I believe was vocalized and exapted to become an audible signal during play behaviour and also took on a mediating and communicative function in fight or flight situations.  " 


AFSP (American Foundation for Suicide Prevention) (2009)

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