Annual Review of Political Science
Vol. 23:441-465 (Volume publication date May 2020)
First published as a Review in Advance on March 9, 2020
Does ethnic diversity erode social trust? Continued immigration and corresponding growing ethnic diversity have prompted this essential question for modern societies, but few clear answers have been reached in the sprawling literature. This article reviews the literature on the relationship between ethnic diversity and social trust through a narrative review and a meta-analysis of 1,001 estimates from 87 studies. The review clarifies the core concepts, highlights pertinent debates, and tests core claims from the literature on the relationship between ethnic diversity and social trust. Several results stand out from the meta-analysis. We find a statistically significant negative relationship between ethnic diversity and social trust across all studies. The relationship is stronger for trust in neighbors and when ethnic diversity is measured more locally. Covariate conditioning generally changes the relationship only slightly. The review concludes by discussing avenues for future research.
Does ethnic diversity erode social trust? This question is the quintessential derivative of the wider debate about whether the positive interpersonal ties characteristic of socially cohesive societies can be preserved when societies’ inhabitants to a decreasing extent share a common ethnic background. The answer to this question is crucial for understanding the potential challenges that developed societies are facing from increasing ethnic diversity stemming from immigration and refugee settlement. It also provides a potential explanation for the challenges to governance in countries that have historically been ethnically heterogeneous (Alesina et al. 1999, Alesina & Glaeser 2004). Further, because social trust stimulates cooperation between individuals (Gächter et al. 2004), the link between ethnic diversity and trust provides a plausible explanation for why ethnic diversity has been found to inhibit the enactment of redistributive welfare policies (Alesina et al. 1999, Alesina & Glaeser 2004).
The link between ethnic diversity and social trust has been studied extensively for around 20 years, and this line of research has generated a plethora of different findings. As highlighted in recent reviews of related outcomes, the evidence on the relationship between ethnic diversity and trust is far from conclusive (Schaeffer 2014, ch. 2; van der Meer & Tolsma 2014; Dinesen & Sønderskov 2018). Therefore, to gauge the major insights that this line of work has produced, we systematize the literature in a narrative review and quantify key overall patterns through a meta-analysis. Previous reviews of trust, and the related wider phenomena of social cohesion and social capital, either have been purely narrative (Portes & Vickstrom 2011, Morales 2013, Koopmans et al. 2015, Dinesen & Sønderskov 2018) or have quantified results using crude counting strategies (i.e., tallying the number of significant relationships) (Schaeffer 2014, ch. 2; van der Meer & Tolsma 2014), which might overlook more subtle aggregate patterns. Given the mature state of the literature, the logical next step is to conduct a proper meta-analysis that quantifies the overall relationship between ethnic diversity and social trust based on reported estimated coefficients and the associated uncertainty estimates, and also breaks the relationship down by theoretically pertinent categories.
In the following, we first clarify the core concepts before pinpointing three essential debates in the literature. Then, based on the results from the meta-analysis, we highlight key findings. We conclude the review by discussing avenues for future research on the relationship between ethnic diversity and social trust.