Not only do these island « micro-spaces » present scientists with the obviously interesting opportunity to analyse changes occuring at this very moment, but also confront them with two questions having epistomological and methodological implications : to what extent, in our part of the word, is it still appropriate to speak of insular societies without significant distortion of meaning, considering the extent to which life styles have become uniformatised ? Furthermore if one is to retain the hypothesis of distinctiveness for these communities, at what level and in what manner can it be detected and eventualy measured ? Because of their relative isolation and their geography, these islands have conserved, longer than is usually the case elsewhere, an originality which still has repercussions for their communities of the late twentieth century. Their identity is based on the strong bond uniting a group of individuals to a precise and particularly well delimited site. It remains to be seen how the insular heritage adapts to modernity. Analysis of the degree to which these micro-communities are open, mobile, or magnets for the outside world demonstrates the validity of this approach, and confirms that insularity acts as a filter tending to impose specific directions of development on communities which continue to define themselves primarily through their close attachement to their small island terrain.