Japan is homogenous. (Generally speaking) Americans are isolated against not only the world but also each other as a result of sparely populated areas, car culture + tech (no interaction with others), and media feeding the average American fear stories all day.
Robert Putnam studied[0] the civic engagement and social trust of diverse/homogeneous societies and found that factor alone sufficient explanation. Fewer Americans live in places as sparsely populated as those our ancestors did.
