 The large field of game theory is extensively explained in other lemmas in this encyclopedia (see among others the entry on  game theory).  This field of research has been very active since the appearance of the seminal book (Von Neumann and Morgenstern 1944). Similarly, social choice theory and in particular voting theory (see entries on  social choice theory  and  voting methods)  were already thriving fields of research long before the term social software came along.