“Among the most important such innovations is the human love of using symbolic markers to show our group memberships. From the tattoos and face piercings used among Amazonian tribes through the male circumcision required of Jews to the tattoos and facial piercings used by punks in the United Kingdom, human beings take extraordinary, costly, and sometimes painful steps to make their bodies advertise their group memberships”
―
Jonathan Haidt,
The Righteous Mind: Why Good People are Divided by Politics and Religion