Many of our most pressing challenges, from combating climate change to dealing with pandemics, are collective action problems: situations in which individual and collective interests conflict with each other. In such situations people face a dilemma about making individually costly but...

Group identity is known to exert a powerful socio-psychological influence on behaviour but to date has been largely explored as a uni-dimensional phenomenon. We consider the role of multiple dimensions of identity, asking what might happen to ingroup and outgroup perceptions and the resulting...