This brief section discusses properties of shared humor and the resulting constraints which humor imposes on communication. First, consider the important communicative functions of humor, many of which were discussed above. Humor can communicate both positive and negative judgments, with corresponding social consequences, including, on the one hand, release of group tension, or liberation from negative interpretations of one's own experience, and on the other hand, aggression, perceived superiority, and ridicule. To summarize in terms of the present theory:
Rule of Inference: If a situation lacks either N or V in one person's interpretation, laughter by another implies that the other affective interpretation is present in that other person's mind, and may be used to infer the presence of that N or V interpretation.
This rule, which is a logical consequence of the present theory of humor, can be used to infer the particular communicative impact of laughter in any given situation. The rule may be used not merely by the analyst in understanding the intentions of participants in a situation, but also, given a little training and practice, by the participants, themselves, in interpreting each others' laughing behavior.
The converse consequence of the theory is that the avoidance or suppression of laughter functions to avoid sending the situationally relevant N or V message. That is, when a person suppresses laughter in a situation, the purpose is to avoid sending a presumably inappropriate evaluative message. Similarly, feigned laughter is used to communicate the relevant (that is, otherwise absent) evaluative message. People are capable of producing the sounds of laughter at will, so it follows that this can be done calculatedly and for a purpose -- without necessarily perceiving humor (that is, feeling that things are really acceptable in the situation, or in other situations, feeling that there is really something wrong). Laughter can be performed without feeling, without true humor perception, for the purpose of communicating the contextually relevant message.
But whether laughter is actual, feigned, or avoided, it is to be understood in context. That is, the communicative impact of the judgment of normality or of moral violation must be indexed to the perceiver, and to the situation in which the funny event occurs or is presented. This indexing is required by the subjective nature of moral, affective evaluations, and it has the purpose of determining the particular communicative impact of laughter by a given person in a given context for a given other person.
For example, laughter ``at the expense'' of a group or individual is where the laughers may be interpreted as viewing that group or person as responsible for a moral violation. This is the heart of ridicule. Or when the television vampire laughs gruesomely at his or her victim, why is the laughter threatening (to the victim)? Because it demonstrates the presence of an N interpretation in the mind of the the vampire, who thus can be seen as finding it normal, acceptable, and desirable that the victim is to be killed. On the other hand, shared laughter in a situation of tension -- that is, where some apparent violation is present in the participants' minds -- shows that people suddenly see the situation as acceptable or normal, and thus it relieves or signals relief of tension. In any of these cases, the element, N or V, which otherwise appeared absent to those interpreting the laughter is added to the participants' view of the situation.
When laughter is elicited in the interpreter by the original laugher, that is, when laughter is shared, there are significant communicative consequences. Consider next, then, what shared humor implies, and what constraints are imposed on those who wish to make others laugh. The central property that follows from the present theory and the very nature of communication is that shared humor requires a sharing of affective evaluations. Clearly, this requires considerably more mutual understanding and agreement than passive listening, since agreement at the level of moral interpretation is not necessary simply to listen. Therefore sharing humor implies high-quality communication as well as shared affect and attitudes.14
Since failure of shared humor (jokes told to those that don't share the attitudes necessary to find them funny) may offend (Level 3 from Table 1) or confuse (Level 1 from Table 1) the listener, effective joke-tellers are constrained to tailor their jokes to their audiences' moral viewpoints. This can be understood in terms of the present theory in combination with the sociolinguistic theory of language style as ``audience design'' (Bell, 1984), which details how it is that speakers tailor their speaking style to their listeners. If a speaker wants to have an audience laugh along with her, she must present a situation in a joke or other format which violates their norms and at the same time seems acceptable in some way to them. This is a tight-rope walk on the emotions; she can't go too far in either direction (evoking too-strong feelings of violation, or evoking insufficient feelings of violation), or she will fail to get her audience to laugh. So the humorous speaker must either share or, at least, understand the values of her audience, so as to monitor what she says so as to prevent slipping off either side of this emotional fine line along which any effective comic must walk.
The same is true in any instance involving humor and intentional commucation. If one wishes to ridicule someone by laughing at them, one must know that they share or at least respect one's views of what is a moral violation; otherwise it will not bother the target of one's ridicule when, by laughing at them, one communicates one's view that they are violating moral norms. And if in another type of situation one wishes to relieve group tension by introducing a humorous, perhaps deadpan, or idiotic, interpretation of the situation which otherwise constitutes a violation to those present, then it must be possible to convince the other people that the situation can in fact be seen as normal; if the others don't share the ability to pull back enough to get a normalized perspective, one's joking efforts at tension-reduction will fall flat. So anytime one wishes to communicate something by humor, shared values are essential, and if one doesn't actually share the values of one's audience, one must at least be able to understand and speak to their values, or the communication will fail or be misinterpreted.