In this contribution, we review research that uses a cross-fertilisation approach to integrate developmental and social-psychological perspectives on how identities are formed and changed over time and how identity processes are genuinely social, being embedded in social contexts and fed by social contents. First, we outline the three-factor identity model as a parsimonious approach to understanding the dynamics of identity development. Second, we review empirical studies with longitudinal approaches to shed light on how identity processes are embedded in key contexts such as family, friendships and society at large through behaviours such as civic engagement. Third, we discuss the interplay between personal and social identities. We conclude by highlighting how adopting a cross-fertilisation approach that combines social-psychological and developmental perspective can significantly advance the theoretical understanding of identity dynamics. Finally, we address similarities and differences between personal identity and social identity approaches, and we provide an agenda for future research.

Around the world, members of racial/ethnic minority groups typically experience poorer health than members of racial/ethnic majority groups. The core premise of this article is that thoughts, feelings, and behaviors related to race and ethnicity play a critical role in healthcare disparities. Social psychological theories of the origins and consequences of these thoughts, feelings, and behaviors offer critical insights into the processes responsible for these disparities and suggest interventions to address them. We present a multilevel model that explains how societal, intrapersonal, and interpersonal factors can influence ethnic/racial health disparities. We focus our literature review, including our own research, and conceptual analysis at the intrapersonal (the race-related thoughts and feelings of minority patients and non-minority physicians) and interpersonal levels (intergroup processes that affect medical interactions between minority patients and non-minority physicians). At both levels of analysis, we use theories of social categorization, social identity, contemporary forms of racial bias, stereotype activation, stigma, and other social psychological processes to identify and understand potential causes and processes of health and healthcare disparities. In the final section, we identify theory-based interventions that might reduce ethnic/racial disparities in health and healthcare.

Even without legal ownership, groups can experience objects, places, and ideas as belonging to them ('ours'). This state of mind-collective psychological ownership-is understudied in social psychology, yet it is central to many intergroup conflicts and stewardship behaviour. We discuss our research on the psychological processes and social-psychological implications of collective psychological ownership. We studied territorial ownership, in different parts of the world and at different geographical levels, offering not only a cross-national but also conceptual replication of the processes. Our findings show that collective psychological ownership is inferred based on primo-occupancy, investment, and formation. Further, we demonstrate that collective psychological ownership can have positive intragroup and negative intergroup outcomes, which are guided by perceived group responsibility and exclusive determination right. We then discuss ownership threat (losing what is 'ours'), and we consider the role of group identification in ownership-related processes. We conclude by providing directions for future research.