“…A competing class of theories assumes that social preferences themselves are flexible and to some degree dependent on the context frame (e.g., Akerlof & Kranton, 2000;Bacharach, 1999Bacharach, , 2006Bacharach & Bernasconi, 1997;Brewer & Kramer, 1986;Gold & Sugden, 2007a, 2007bKramer & Brewer, 1984;Sugden, 1993Sugden, , 2000Sugden, , 2015Wit & Wilke, 1992). Foremost, group identity theories assume that players first categorise all players, including themselves, into groups.…”