If one is asking about the boys' tentative attemts at forming a society on the island and not society at large, there are plenty of examples: physically the boys' hair along with their clothes have become ragged and dirty, their toilet habits have come carelessly close to their bathing area, they have stopped almost all work on their living quarters and the schedule that Ralph has set up for maintaining the rescue fire is not being followed.
Mentally, the best example to give would be the rock throwing incident between the littleun and Roger. The line between civilization and anarchy- good vs evil - is getting thinner. The old rules of Mr. Policeman and Misses Teacher are becoming fainter. Thus, the rule of "Don't throw rocks at people!" is barely remembered, but still there. As that rule and others that keep the inner beast at bay are forgotten, and as more time passes by on the island, beware, the rocks will start to strike the bodies.