The Economy and Social Norms.Law as Culture

Popularly, we tend to think of formalized/institutionalized laws - i.e., laws that have been codified and written down - as the only regulations that influence our behavior. However, such a notion privileges (particular Euro-American orientations towards) the written word and neglects that there are many different kinds of processes and forces that regulate our actions. As such, how can we conceptualize "customs"/"culture" as "law"? Are cultural rules necessarily "informal" or only "unofficial"? Do cultural rules become codified, or do institutionalized laws become imbued in our culture? Or is this a back and forth process?