In my quest to better understand basic principles of group behavior, I reviewed Intergroup Relations, by Maryland B. Brewer and Norman Miller (1996) [this work appears to be out of print].  The stated focus this book is to better understand “the causes and consequences of the distinctions between ingroups (those groups to which an individual belongs) and outgroups (social groups that do not include the individual as a member).  At the outset, the authors note “the apparently universal propensity to differentiate the social world into ‘us’ and ‘them.’”  (Page xiii).

It was my suspicion that basic principles of social psychology would give me a deeper context for understanding many modern conflicts.   I was not disappointed.  By the way, these same principles appear in all basic social psychology books.  Nothing I mention here is tentative or controversial among social scientists.

According to Sherif (1966) “whenever individuals belonging to one group interact, collectively or individually, with another group or its members in terms of their group identification, we have an instance of Intergroup behavior.”  (Page 2)   Such social categories “tend to be less rational than other categorizations in that the beliefs we hold about social groupings often do not rest on firm evidence of actual Intergroup differences.”  (Page 6)  Once we establish categories, “we are biased toward information that enhances the differences between categories and less attentive to information about similarities between members of different categories.”  (Page 7).

We live in a pluralistic society.  Therefore, individuals are simultaneously members …