Dynamic Remodeling of In-Group Bias During the 2008 Presidential Election Newer:Positive Interactions Promote Public CooperationOlder:Direct Reciprocity and Costly Punishment: Generous Tit-for-Tat Prevails PostedJuly 25, 2013 AuthorScienceSites Categories2009, social-behaviors-beliefs, journal-article Tags2009, Cooperation, Intergroup, Politics