Evidence/studies you may be interested in... since they directly contradict some of your points.
– As diversity increases, politics becomes more tribalistic.
http://www.nytimes.com/2016/01/06/business/economy/racial-identity-and-its-hostilities-return-to-american-politics.html?_r=0
– High ethnic diversity has a negative effect on innovat…
– High ethnic diversity has a negative effect on innovation, but high “values diversity” has the opposite effect, as long as ethnic diversity is low. The best innovation happens in countries that are ethnically homogenous but diverse in values orientation.
– In Switzerland, social peace between diverse factions isn’t maintained by integrated coexistence, but rather by strong topographic and political borders that separate groups and allow them autonomy.
– “Our analysis supports the hypothesis that violence between groups can be inhibited by both physical and political boundaries.” Link.
– Data from the National Longitudinal Study of Adolescent Health showed that multiethnic diversity decreases happiness among all groups, and most markedly for the downscale and economically dispossessed.
– “[E]thnic heterogeneity [diversity] explains 55% of the variation in the scale of ethnic conflicts, and the results of regression analysis disclose that the same relationship more or less applies to all 187 countries. … [E]thnic nepotism is the common cross-cultural background factor which supports the persistence of ethnic conflicts in the world as long as there are ethnically divided societies.” Link.
– Genetic Similarity Theory (GST) could help explain why diverse groups in close proximity increases ethnic conflict and ethnic nepotism.
– Genetic diversity has contributed significantly to frequency of ethnic civil conflict, intensity of social unrest, growth of unshared policy preferences, and economic inequality over the last half-century.
– Using social science data and computer modeling, researchers found that policies that attempt to create neighborhoods that are both integrated and socially cohesive are “a lost cause”.
– The numbers and the genetic distance matter. Minority groups that get above a certain critical mass, and that are culturally distant from the majority culture, begin to self-segregate from the majority, moving society toward division and away from cooperation.
Evidence/studies you may be interested in... since they directly contradict some of your points.
– As diversity increases, politics becomes more tribalistic.
http://www.nytimes.com/2016/01/06/business/economy/racial-identity-and-its-hostilities-return-to-american-politics.html?_r=0
– High ethnic diversity has a negative effect on innovation, but high “values diversity” has the opposite effect, as long as ethnic diversity is low. The best innovation happens in countries that are ethnically homogenous but diverse in values orientation.
http://www.tandfonline.com/doi/abs/10.1080/13504851.2015.1130785
– Diversity hinders between-group cooperation at both the one-on-one and group levels.
http://spq.sagepub.com/content/78/4/324.short
– Social trust is negatively affected by ethnic diversity, case study in Denmark from 1979 to the present.
http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9477.2012.00289.x/abstract
– Ethnic homogeneity and Protestant traditions positively impact individual and societal levels of social trust.
http://esr.oxfordjournals.org/content/21/4/311.short
– “In longitudinal perspective, [across European regions], an increase in immigration is related to a decrease in social trust.”
http://sf.oxfordjournals.org/content/93/3/1211.abstract
– Immigration undermines the moral imperative of those who most favor welfare benefits for the neediest.
http://cos.sagepub.com/content/53/2/120.abstract
– The negative effect of community diversity on social cohesion is likely causal.
https://academic.oup.com/esr/article/32/1/54/2404332/Does-Ethnic-Diversity-Have-a-Negative-Effect-on
– In Switzerland, social peace between diverse factions isn’t maintained by integrated coexistence, but rather by strong topographic and political borders that separate groups and allow them autonomy.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0095660
– “Our analysis supports the hypothesis that violence between groups can be inhibited by both physical and political boundaries.” Link.
– Data from the National Longitudinal Study of Adolescent Health showed that multiethnic diversity decreases happiness among all groups, and most markedly for the downscale and economically dispossessed.
https://www.researchgate.net/publication/283881736_Happiness_in_modern_society_Why_intelligence_and_ethnic_composition_matter
– Using data from US states, study finds a negative relationship between ethnic polarization and trust.
http://onlinelibrary.wiley.com/doi/10.1111/j.1465-7287.2010.00215.x/abstract
– Increasing social pluralism (diversity) is correlated with increased chance of collective violence.
https://www.jstor.org/stable/425106?seq=1#page_scan_tab_contents
– “[E]thnic heterogeneity [diversity] explains 55% of the variation in the scale of ethnic conflicts, and the results of regression analysis disclose that the same relationship more or less applies to all 187 countries. … [E]thnic nepotism is the common cross-cultural background factor which supports the persistence of ethnic conflicts in the world as long as there are ethnically divided societies.” Link.
– Genetic Similarity Theory (GST) could help explain why diverse groups in close proximity increases ethnic conflict and ethnic nepotism.
http://www.sciencedirect.com/science/article/pii/S0191886912005569
– Genetic diversity has contributed significantly to frequency of ethnic civil conflict, intensity of social unrest, growth of unshared policy preferences, and economic inequality over the last half-century.
https://www.nber.org/papers/w21079
– Using social science data and computer modeling, researchers found that policies that attempt to create neighborhoods that are both integrated and socially cohesive are “a lost cause”.
http://msutoday.msu.edu/news/2013/study-asks-is-a-better-world-possible/
– The numbers and the genetic distance matter. Minority groups that get above a certain critical mass, and that are culturally distant from the majority culture, begin to self-segregate from the majority, moving society toward division and away from cooperation.
http://www.ifs.org.uk/uploads/publications/wps/WP201530.pdf
– School integration (forced proximate Diversity) will not close race achievement gaps.
http://www.usnews.com/opinion/knowledge-bank/articles/2016-01-08/the-academic-benefit-of-reducing-school-segregation-may-be-overblown
– Exclusionary dating is a natural consequence of racial diversity.
http://sf.oxfordjournals.org/content/89/3/807
– Company diversity policies don’t help minorities or women, and they psychologically discriminate against White men.
https://hbr.org/2016/01/diversity-policies-dont-help-women-or-minorities-and-they-make-white-men-feel-threatened
– Greater classroom and neighborhood diversity is linked to stronger tendencies to choose same-ethnic rather than cross-ethnic friends.
http://onlinelibrary.wiley.com/doi/10.1111/jora.12248/abstract
– A longitudinal test of the impact of diversity finds that it makes existing residents feel unhappier and more socially isolated.
https://www.academia.edu/3479330/Does_Ethnic_Diversity_Have_a_Negative_Effect_on_Attitudes_towards_the_Community_A_Longitudinal_Analysis_of_the_Causal_Claims_within_the_Ethnic_Diversity_and_Social_Cohesion_Debate
Gender diversity does not promote nonconformity in decision-making bodies. (But individual ability diversity does.)
http://pubsonline.informs.org/doi/abs/10.1287/mnsc.2015.2382