I read in the The Economist that
in most countries, anti-Semitism rises or falls in concert with nationalism and identity politics. David Feldman of the Pears Institute notes the importance of “competitive victimhood”, in which claims of oppression by Jews, Muslims and other groups step on each others’ toes. Dariusz Stola, head of the Polin Museum of Polish Jewish History, says the same is true in Poland, where the national story is one of victimisation by Germany and Russia. It is more accurate, he thinks, to see anti-Semitism as part of a general wave of chauvinist sentiment since the migrant crisis of 2015; levels of hostility to Muslims, gays and Roma have risen too. Says Mr Stola: “Xenophobia is not selective.”
Since most observational studies on this are going to have trouble with confounders, are there any controlled experiments of inducing some level of xenophobia and measuring its "halo effect" against out-groups not specifically targeted (by the experimental message)?