such as job promotions, awards, and praise, are designed to encourage people to behave and act in the interest of the whole community. Punishments, such as public embarrassment, fines, and even imprisonment can prevent people from acting against the community's best interests, regardless of their values.
People need their communities to function smoothly. Because of this, humans most often behave in orderly, fair, and predictable ways. If there were no rules, the majority of people would probably continue to interact positively, like the subjects in the online avatar study. However, there would always be a minority who would not, with serious consequences. This is why a society without rules is unlikely to become a reality any time soon at least not in the real world.