Migration and integration are driven by a complexity of factors. This complexity urges a re-examination of economic theories of immigration. In economics, immigrants' integration is studied based on Beckerian-Mincerian human capital view. People are expected to smoothly fit into their new environments and be motivated solely by their reason to migrate: Investing in human capital. But this leaves individuals' distinctness in their adaptation into receiving societies unexplained. Moreover, the problem carries over into understanding their change in their interaction with others, and together this leads to the problems in measurement and thus policy-making. Indeed, as guest workers in Europe a half- century ago were not just workers, any migrant today cannot be considered as an isolated and static being. Further, migration cases often are not pure but mixture of various migration types. This paper proposes a shift from a static economic integration framework to an identity-based acculturation theory in connection with the club theory idea. The evolution of club occurs through a direct interaction between individuals that is central to social and economic activity. Individuals with social identities evolve as the mix of interacting social identities in a club (society) evolves. In this sense, the approach goes beyond traditional social identity theory, where social identities do not change, to a dynamic view where one gives up a native social identity to an extent and acquires a new hybrid one while others do the same. This study aims to provide an approach that serves a basis for empirical research on immigration and adaptation. By pointing out the limitations of the current theories, it also aims to exhibit necessary inclusions for further theoretical studies of immigration and adaptation.

Keywords: immigration, heterogeneity, integration, adaptation, interaction, accul- turation, human capital, social identity, club theory.