Blurton Jones (1967; 1971; 1972) and McGrew (1969; 1972) were prob­ ably the first to study systematically the behaviour of young children and their peers in British nursery schools. Their work is a basic reference for biologists and psychologists who study the behaviour and interaction of young children (see the example of “rough-and-tumble play” described by Blurton Jones, 1972). From 1970 our laboratory in Besangon started doing research work in child day-care centres (children under three years of age) and kindergartens (children from two to six years of age) to try and list those behaviour sequences of young children in their peer groups that remained stable over a period of weeks and months (Montagner, 1974; 1978; 1979; 1983; Montagner & Henry, 1975; Montagner, Restoin & Henry, 1982; Montagner et al., 1978; 1979; 1981). The groups only varied in size at certain times of the year with the arrival or departure of a child or a small number of children for social or medical reasons. After the necessary descriptive stage at the beginning, a resolutely functional and ontogenetic approach was adopted:

1. Possible correlations were sought, in children aged from 18 to 36 months, between the behaviour of a child as an emitter and the behaviour of one or more receivers during activities that were created by the children themselves or by their nurses. In this way it was possible to identify

progressively the most probable consequences or functions of a type of behaviour according to age, sex, context, etc.