The purpose of this research is to consider an additional dimension to the anthropological study of a social group. This new approach consists to systematically consider the biological reality of the social individual for the analysis of its social or individual behaviour, as well as the cultural elements that can be observed within a community of a particular ethnic group.
This socio-biological reality is bound to the structures and the very functioning of the Human brain, a component of elements and mental structures inherited or acquired. This duality between what is inherited and what is acquired, and especially the way it is expressed, is in the heart of the subject of this thesis. The social individual builds itself according to this duality, caught between the essence, the complex biology of the organism and especially of the human brain, and the existence which is all the behavioural features that the individual will develop according to its social environment in which it evolves. The social individual is defined according to what it has inherited and acquired, as well as to the incompatibilities between this inheritance and these acquired experiences, the importance of these incompatibilities and the behavioural elements that they will affect. Because of that, the social individual and its individuality will be forged between the anvil of the biological, of what is inherited, and the hammer of the social. This means that the social individual is forged under constraint.
I will conduct this analysis of the duality of the social individual and its constraints through a concrete and particular example: the social individuals of two communities of the Huli ethnic group, Kulu and Kerniba. It is possible to do this analysis of the reality of the existence by observing a single social group, but this reality can become very different when confronted to other realities of existence. In this example of Kulu and Kerniba, a third social constant must be taken into account: the western presence. This third reality of existence, totally different from the two first ones, will differently influence the existence of the individuals of both Huli communities. This western existence becomes a factor of influence, an entropy of which impact will be different depending on the differences between the social and natural environments of studied groups.