Multiculturalism, in Singapore and all over the world, is one of the challenges of modern society and industrial civilization. Strong exposure to other ethnic groups living in the same country can promote the development of a common culture as well as psychosocial stress between ethnic majority and minority. Interestingly, the distinction between in-group and out-group is becoming not only defined by ethnicity but also by cultural belonging. Culture defines the identity of a group as much as ethnicity does. In terms of multiculturalism, Singapore represents a very unique case. In Singapore the definition of in-group and out-group is a dynamic process. The purpose of this study is to highlight the social dynamics of culture and ethnicity within in-groups and out-groups in a multicultural society. In this study we will investigate the brain and physiological responses in a sample of 50 Singaporean participants. They will be exposed to both in-group and out-group faces in two different contexts: ethnicity-related contexts (EC; foreign country) versus culture-related contexts (CC; local). We propose to adopt an integrative approach by combining neuroscience (fMRI), psychophysiology (heart dynamics, skin conductance and thermal regulation) and socio-psychology and attitudes to others (Multiculturalism, Refined Schwartz Value survey, Right-wing Authoritarianism Scale) in a multi-level analysis. This study will cover the complex integration between affective and cognitive mechanisms and ethnic-cultural factors which all together drive the final sense of belonging. Findings from this project will have high research relevance to the literature on individual and environmental social factors that influence the definition and distinction of cultural in-group and out-group. The study will also give new insight towards a comprehensive framework for deeply understanding the social dynamics in multicultural and multiethnic societies such as Singapore.