Clearly defined relationships of reciprocal, ritual, mildly abusive behaviour, between persons who are not only permitted but expected to behave in ways that would be offensive or insulting to persons not so related. These relationships express a form of friendliness by a show of mild hostility. Joking relatives are expected not to take offence but to respond in kind.
Joking relationships are therefore the obverse of avoidance relationships and are often found in the same social context. It has frequently been argued, indeed, that they serve the same social function. For example, A. R. Radcliffe-Brown (African Systems of Kinship and Marriage, 1950) maintains that ‘in the building of social structures means must be provided for avoiding, limiting, controlling, or settling conflict. In the new structural situation resulting from marriage…while there is a union of the husband and wife the two families…remain separated, only linked together by their separate connection with the new family…It is the separateness of the two groups, together with the need of maintaining friendly relations between them, that has to provide the basis for their personal relations’. In this situation, the social separation of the man and his wife's relatives is symbolically represented in sham hostility and the readiness not to take offence, both governed by strict conventions. Thus, for example, in agnatic (descended by male links from the same male ancestor) kinship systems, it is often considered appropriate for a sister's son to express symbolically his relationship to his uncle in joking customs of privileged familiarity (a situation found among the Winnebago and certain other North American tribes). Similarly, among the patrilineal Hutu of northern Rwanda, a joking relationship exists between a man and his matrilateral cross-cousins, male or female, whereas his behaviour towards his female patrilateral cross-cousins has to be kept discreet and formal.