ingroup against an outgroup ingroup advantage phenomenon psychological factors which drive mutual hostility ingroup advantage phenomenon ingroup against an outgroup http://www.understandingprejudice.org/apa/english/page7.htm ingroup against an outgroup Research about “ingroup favoritism” ingroup against an outgroup ingroup against an outgroup ingroup against an outgroup ingroup against an outgroup brains are hard-wired ingroup against an outgroup