I previously summarized a paper which showed that an evolutionary population can cooperate if there's a subpopulation of "corrupt policers", hypocrites who punish others for defecting, while also defecting themselves. A small population of corrupt policers is still better than an entire population of defectors, so the conclusion was that corruption can be a force for good.
"Evolving Righteousness in a Corrupt World" is a paper that disagrees with those conclusions. They begin with the observation that in human societies, corruption doesn't really appear to be a force for good. Then they show that there is an alternate possibility of a "righteous" population, where nearly everyone is a cooperative policer.
The critique in this paper is actually quite similar to the critique I made at the end of my last post. I said that it didn't seem to describe police officers very well, since police are publicly funded. So what would happen if we had a game where all cooperative non-policers paid a small fee to the policers? The fee doesn't even need to be large, it can be a small perturbation.
This paper shows that this small change allows the existence of
righteousness under certain conditions.
And that's this paper in a nutshell.
To promote righteousness, you basically need two things. You need punishments to be more egalitarian (i.e. policers get punished almost as badly as non-policers do when they defect), and you need punishments to be harsh (at least harsh enough to offset the benefit of defecting). In the context of police, that means not giving police officers special treatment when they break the law. Hey, that seems like it should be a fairly obvious democratic principle!
On the other hand, I'm still wondering if this is a good model of the police. After all, not everyone is a police officer, and those who are police officers aren't all corrupt. Maybe you can think of certain people as being police for game theory purposes simply because they'll report crimes to the police. Or maybe the model just needs further modification. I'm sure there's some way to fund the police department without having the police be zombies who take over the entire population.