It is recognized that social phenomena result as much from external determinisms as from an aggregation of individual or collective actions. It is in this context that the scientific effort in this study aims to understand the motivations or reasons for acting of populations settled illegally in the Marahoué National Park (PNM). On the theoretical-methodological level, we referred to the actionist paradigm through Garfinkel's ethnomethodologism and that of Boudon's methodological individualism, whose substrate claims the recognition of a more or less assertive form of strategic behavior of actors. Through semi-structured interviews and participant observation, the etiological study of park infiltrations shows, on the one hand, that strategic rationality highlights the gain/loss relationship and, on the other hand, that the identity and relational aspects are based on the representation and interpretation that these populations have in relation to their symbolic and normative references. Clearly, the motivations of so-called clandestine populations respond to a desire to satisfy social, economic and psychological needs
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