Previous scholarship has highlighted the validity and reliability of a bidimensional acculturation model for migrants, allowing for simultaneous endorsement of one’s heritage and national culture. So far, however, no empirical research has explored whether the bidimensional acculturation model can be extended from migrants to members of the mainstream society (i.e., locals). Thus, the broad aims of this dissertation were threefold: (a) to validate a new framework, termed the Extended Acculturation Model for Locals (EAML), which consists of two dimensions (i.e., national culture maintenance and multicultural adaptation), and (b) to examine the outcomes as well as (c) antecedents of these dimensions. In this dissertation, the General Introduction outlines the growth of multiculturalism across societies, followed by a review of existing acculturation research on migrants and the analogous work on locals. It is noted that migrants’ acculturation process implies individual-level changes, whilst locals’ acculturation process implies attitudes and behaviours which hinder or foster migrants’ individual-level changes. The Study Overview outlines the dimensionality of locals’ acculturation process, their adjustment outcomes and antecedents. Using a modified Vancouver Index of Acculturation (Multi-VIA), Study 1 found support for a bidimensional acculturation model for locals consisting of two reliable and valid subscales indicating national culture maintenance and multicultural adaptation. Study 2 buttresses the validity and reliability of the Multi-VIA across cultures as well as demonstrates the ability of national culture maintenance and multicultural adaptation to predict locals’ sociocultural and psychological adjustment outcomes. Study 3 explains why the correlation between locals’ national culture maintenance and multicultural adaptation is either orthogonal or positive oblique; more specifically, the correlation is moderated by locals’ degree of multicultural exposure, their likeliness to compartmentalize or blend their multicultural identity as well as through high or low self-construal endorsement. Study 4 demonstrates that national culture maintenance and multicultural adaptation predict local employees’ organizational behaviour in multinational corporations. Study 5 revealed that cultural values endorsed at the individual-level predicted locals’ national culture maintenance and multicultural adaptation. Moreover, these individual-level value-outcome associations were moderated by compatible societal-level pro-diversity messages. The General Discussion reviews all of the study findings as well as discusses their implications. The General Limitations and Future Directions describes the theoretical and methodological shortcomings of the Extended Acculturation Model for Locals whilst setting future directions for research. Last, the Final Remarks stresses the overall strengths of the present dissertation – that is, it fills the present research gap on locals’ acculturation towards multiculturalism, and in turn, provides a new route towards harmonious intergroup relations and social cohesion in mixing societies.

Parentification is a process where children or adolescents assume adult roles before they are emotionally or developmentally ready, which, in turn, disrupts the development of healthy, secure attachment in childhood. Using 1,001 men and women from South Korea and the United States with equal division between males and females and multiple group comparison technique in structural equation modeling, this paper examined the relationship between parentification during childhood and depression during adulthood. It explores the cross-sectional long-term effects of parentification into adulthood, using a retrospective survey technique. This study also confirmed previous research findings that attachment, physical health and family-of-origin dysfunction, parental addiction in particular, significantly predict depression. This study is one of the few studies, using clinical data, that allows a direct comparison between different sample groups in two different countries and by gender.