You might like Jonathan Haidt's book 'The Righteous Mind' - http://righteousmind.com/ http://righteousmind.com/ It has a lot on how people make ethical argumen

You might like Jonathan Haidt's book 'The Righteous Mind' - http://righteousmind.com/ http://righteousmind.com/ It has a lot on how people make ethical arguments in particular which I found quite eye opening (if a bit bleak in terms of its consequences for civic society).