Ethnicity was supposed to become less and less important, as modernization and globalization take place. This chapter discusses how ethnicity has continued to be central to the lives of humans in the twenty-first century, and in some respects has become even more important. Ethnicity is often confused with race, even in academic research. Ethnicity is a social construct, whereas race is based on biological characteristics. Since the 1970s there has been ethnic mobilization and collective action in order to improve the conditions of disadvantaged ethnic groups. There has also been ethnic conflict and discrimination against ethnic minorities. Psychological research using the minimal group paradigm, as well as case studies of ethnic groups such as the Tutu and the Hutsi of Rwanda, demonstrates that there need only be minor or trivial differences between groups in order for individuals to show bias in favor of their ingroup. The arrival of large numbers of dissimilar others in North America and Western Europe has also added fuel to the fire of ethnic conflict.

The concept of identity has long captured the interest of scholars, and its importance in both the social sciences and in society more broadly continues to rise. As the literature surrounding identity has expanded, increased attention has been given to experimental designs that measure the concept, consequences, and correlates of identity.This chapter focuses on racial and ethnic identity withinthe context of experimental methods from both an analytical and methodological perspective. First, the chapter provides an overview of scholarship on the study of identity, highlighting the importance of social identity theory as the starting point for a long trajectory of theoretical and empirical work. Next, design challenges and opportunities are addressed, with specific attention paid to the conceptual use of identity as a variable. The following section provides examples of experimental research on racial and ethnic identity, focusing on ingroup and outgroup studies, and studies that measure political outcomes related to race and ethnicity. One common shortcoming of identity research isthe tendency to use group membership as a proxy for group identity and group consciousness, or to use the terms interchangeably when they are in fact theoretically distinct concepts. I argue that experimental designs may demonstrate the need to disentangle group membership from group identity and group consciousness, and offer a strategy for adapting measurement tools to study identity. The chapter concludes by providing recommendations and identifying areas for future research to expand our understanding of racial and ethnic identity through the use of experiments.