This must rile the PC brigade. To see proof that certain cultures display exemplary behaviours and that maybe not all cultures were created equal.
In my opinion a singular reason is the racial and cultural homogeneity in Japan enables them to emphasize with their fellow citizen and pull together in times of crisis. Hurting and taking advantage of their neighbor in such a situation is like doing the same to themself.
Americans too are brought up with notions of honor and pride and a hard work ethic yet there is underlying anarchy that temporary removal of government brings out.
Sweden is another culturally homogenous nation with a very low crime rate by the indigenous Swedes.
