I believe the answer is: morality
The purpose of morality is to act as some sort of guidance to perform correct behavior that all 'rational' persons should do within a social group. Morality does not necessarily regulated by law, but violating it would definitely make a member of a social group the be negatively perceived by other members.
Morality is the class of rules held by society to govern the conduct of its individual members. It implies the quality of being in accord with standards of right and good conduct.
