On being different: Exploring the relationship between dissimilarity and social inclusion in the workplace
Authors: Sahin Onur 
Published: February 2025

In this dissertation, I investigate how being different from the majority of one’s colleagues shapes social inclusion perceptions at work. In Chapter 1, I introduce the relational demography approach and ingroup projection model as the frameworks of my dissertation and summarize the methods, findings, and broader implications of the empirical chapters that follow. In these chapters, I utilize a multi-method approach consisting of desk research, experimental studies, and large-scale correlational studies to offer six significant contributions to the literature. First, in Chapter 2, an analysis of diversity statements of 84 Dutch private and public organizations showed that most statements include both surface-level (readily visible, such as gender and ethnicity) and deep-level dimensions (more underlying, such as personality and sexual orientation). However, surface-level dimensions were more often included, without clear differences between statements of private and public organizations. Second, in Chapter 3, experimental studies (N = 128 in Study 1; N = 196 in Study 2, recruited via Prolific) established the causal relationship between dissimilarity and social inclusion. Third, in Chapter 4, a survey study with 887 employees of a public organization in the Netherlands revealed that deep-level dissimilarity, rather than surface-level dissimilarity, related to social inclusion and that inclusion explained the relationships between dissimilarity and work-related outcomes. Fourth, in Chapter 5, a survey study with 6,312 employees of another Dutch public organization accounted for multidimensionality and revealed that as employees perceived dissimilarity on more dimensions, they perceived less inclusion. Furthermore, the results showed that dissimilarity in personality, ethnicity/cultural background, age, level of education, work experience, and disability negatively related to perceptions of inclusion, offering a more nuanced understanding of the dissimilarity-inclusion relationship. Fifth, a review of the relational demography literature in Chapter 6 identified four general mechanisms theorized to explain why dissimilarity relates to outcomes: 1) uncertainty, 2) trust, 3) disapproval, and 4) initiated interaction between colleagues. A survey study with 2,409 UK residents (recruited via Prolific) confirmed that all four mechanisms uniquely explained the dissimilarity-inclusion relationship. Sixth, and finally, I found support for the indispensable role of the organizational climate for inclusion across Chapters 4, 5 and 6. In these chapters, a positive climate for inclusion buffered the negative relationships between dissimilarity and outcomes. My research argues for a broader consideration of dissimilarity dimensions beyond the dimensions diversity policies typically focus on, emphasizing the importance of recognizing multidimensionality and the crucial contextual role of climate for inclusion. This dissertation not only enriches our understanding of workplace diversity, but also offers actionable opportunities to mitigate social inclusion disparities.