Schroeder said it’s an adaptive human tendency to categorize people into groups as a way to make sense of our world and not to have to process everything individually. http://www.duluthnewstribune.com/articles/index.cfm?id=60563&freebie_check&CFID=6317538&CFTOKEN=42193062&jsessionid=88303685a0a04e6183b4 www.peoplewho.org