Crime and punishment: The neurobiological roots of modern justice (http://medicalxpress.com/news/2012-04-crime-neurobiological-roots-modern-justice.html)
QuoteA pair of neuroscientists from Vanderbilt and Harvard Universities has proposed the first neurobiological model for third-party punishment. It outlines a collection of potential cognitive and brain processes that evolutionary pressures could have re-purposed to make this behavior possible.
The willingness of people to punish others who lie, cheat, steal or violate other social norms even when they weren't harmed and don't stand to benefit personally, is a distinctly human behavior. There is scant evidence that other animals, even other primates, behave in this "I punish you because you harmed him" fashion. Although this behavior – called third-party punishment – has long been institutionalized in human legal systems and economists have identified it as one of the key factors that can explain the exceptional degree of cooperation that exists in human society, it is a new subject for neuroscience...
Interesting study that may shed light on why humans are the only species that has a police force and judiciary.