"In high-trust societies, punishment is likely to be viewed as attempts to enforce cooperative norms, which encourages others to behave according to such norms. In high-trust societies people may be more likely to notice norm violations such as free-riding on public transportation or having loudphone conversations in public places. And they may be more likely to enforce cooperative norms, also because they trust others to support such norm enforcement. Over time, such activities promote trust and cooperation in such a manner that norm enforcement is less often called for."
Via Howard Rheingold