Interpret a set of players with similar attributes who are all playing the same strategy as a society. Is it consistent with self-interested behaviour for a population to organise itself into a relatively small number of societies? By introducing a framework of approximate substitutes in non-cooperative games we are able to put a bound on the ‘inefficiency’ of such social conformity for arbitrary games. This is then applied, using non-cooperative pre-games, to show that for sufficiently large games there exists an approximate Nash equilibrium in pure strategies for which the population is partitioned into a relatively small number of societies.