Previous studies from America, Israel, and Denmark found that diversity causes a loss of social trust, or the ability of people to interact freely and with an expectation of fair treatment.
This follows many years of research indicating that diversity and community are incompatible, while strong culture makes strong communities and enhances the abilities of the individual. In fact, diversity results in conflict everywhere it is tried but remains popular with politicians because diversity cements totalitarian power despite causing constant internal conflict.
New research summarizes known data and finds that diversity reduces social trust, especially close to home:
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. Taking this as point of departure, this article reviews the existing 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 studied in more local contexts. Covariate conditioning generally changes the relationship only slightly.
This will surprise no one who follows such things. When people have a strong culture, they know how to act so that they will be rewarded; when diversity is present, culture becomes reduced to whatever all groups accept, which is the lowest common denominator.
As always, nature creates branches for a reason. Things differ, and each must go its own way. Trying to make them all into one reflects a human desire to control, and that usually goes badly, because nature is more complex and more intelligent than we are.