Where do tribes come from? Evolutionary origins
What is essential human nature? Where do religion and morality come from? How do religious and non-religious people differ?
What dynamics regulate in-group and out-group interactions and conflicts?
http://mindblog.dericbownds.net/2012/05/blog-post.html brain correlates of whether we help someone suffering
What kinds of political tribes do people belong to today?
What distinguishes liberals and conservatives?
How do people sustain their tribal identities, what psychological shortcuts or errors help?
How can tribal animosities and conflicts be ameliorated?