Link:
Diversity increases social adversity.
A 10% increase in diversity doubles the chance of psychotic episodes.
http://bjp.rcpsych.org/content/201/4/282.abstract?etoc
Diversity reduces voter registration, political efficacy, charity, and number of friendships.
Ethnic diversity reduces happiness and quality of life.
Diversity reduces trust, civic participation, and civic health.
http://www.boston.com/news/globe/ideas/articles/2007/08/05/the_downside_of_diversity/?page=full
Ethnocentrism is rational, biological, and genetic in origin.
http://www.pnas.org/content/108/4/1262.abstract
Ethnic diversity harms health for hispanics and blacks.
http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2012.300787
Babies demostrate ethnocentrism before exposure to non-whites.
http://onlinelibrary.wiley.com/doi/10.1111/j.1467-7687.2012.01138.x/full
Ethnocentrism is universal and likely evolved in origin.
http://www-personal.umich.edu/~axe/research/AxHamm_Ethno.pdf
Diversity primarily hurts the dominant ethnic group.
http://www.theindependentaustralian.com.au/node/57
Ethnic diversity reduces concern for the environment.
http://link.springer.com/article/10.1007%2Fs10640-012-9619-6
Ethnic diversity within 80 meters of a person reduces social trust.
Ethnic diversity directly reduces strong communities.
https://www.msu.edu/~zpneal/publications/neal-diversitysoc.pdf
Ethnically homogenous neighborhoods are beneficial for health.
Diversity in American cities correlates with segregation.
http://fivethirtyeight.com/features/the-most-diverse-cities-are-often-the-most-segregated/
Races are extended families. Ethnocentrism is genetically rational.
It is evolutionarily rational to be friends with someone genetically similar to you.
http://www.livescience.com/46791-friends-share-genes.html
Racism and nationalism are rational and evolutionary advantageous strategies.
http://jasss.soc.surrey.ac.uk/16/3/7.html
Homogeneous polities have less crime, less civil war, and more altruism.
http://www.theindependentaustralian.com.au/node/57
States with little diversity have more democracy, less corruption, and less inequality.
http://www.theindependentaustralian.com.au/node/57
There is extensive evidence people prefer others who are genetically similar.
http://psychology.uwo.ca/faculty/rushtonpdfs/n&n_2005-1.pdf
Our analysis shows that peace does not depend on integrated coexistence, but rather on well defined topographical and political boundaries separating groups
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0095660
The more integrated a neighborhood is, the less socially cohesive it becomes, and vice versa.
http://msutoday.msu.edu/news/2013/study-asks-is-a-better-world-possible/
The more ethnically diverse the people we live around, the less we trust them.
http://macaulay.cuny.edu/eportfolios/benediktsson2013/files/2013/04/Putnam.pdf
Ethnocentrism, often thought to rely on complex social cognition and learning, may have arisen through biological evolution.
http://jasss.soc.surrey.ac.uk/16/3/7.html
Diversity experiments in Germany end in disaster
Immigrants in Norway are a net loss to the economy
http://www.emnbelgium.be/publication/report-norwegian-welfare-and-migration-committee
Immigrants in Sweden are a net loss to the economy
http://www.amid.dk/pub/papers/AMID_48-2006_Jan_Ekberg.pdf
Denmark saved billions by restricting immigration:
Increases in diversity correlate with problems worldwide, and the downsides of diversity effect everyone, it’s a universal human problem:
More diversity in police departments correlates with more abuse, poorer performance and less trust:
http://www.mediafire.com/?1fe8x0egftpbp6f
Decreased community spirit, decreased altruism, and depressed social capital, less ethical behavior, more crime, fear, isolation and depression:
http://www.city-journal.org/html/eon2007-06-25jl.html
Also, a nice little study from Cornell University about how segregation creates peace:
