You've taken the analogy more literally than it was intended.
I didn't mean to say that "if everyone (including guilty people) is honest with the police then guilty people will be caught." That would have been naive. My point is that talking to the police is a prisoners dilemma when considered as a game played only between innocent people.
My point is that the police can't do their job without information, and almost all information given to the police is volunteered by innocent people. Far fewer crimes would be solved if everyone clammed up when the police knocked on their doors, and that'll inevitably lead to more crime.
But innocent people would have no obvious reason to know the existence of each other in relation to the investigation of a crime - in fact, investigators would tend to think that indicated some knowledge of the crime and make that person a viable suspect, in which case you are not suspected innocent and it's not in your interest to talk to the police.
The prisoner's dilemma is specific for a reason - nothing in its description is ambiguous. Please do not call this situation a prisoner's dilemma when it is not. The prisoner's dilemma implies a game with specific rules, and by applying that name to some other situation, you are changing the rules of the game and making it into something else entirely.
Information to help solve crimes can still be provided to police with a lawyer present, which is something that everyone should do when being questioned. Full stop. It's not about being moral or immoral, it's about basic self-preservation.
It's easy enough to ground this in game theory to make the analogy more explicit.
Say there's a street with two houses. In the event of a crime, people in the houses can volunteer information to the police. They don't know ahead of time whether their information is pertinent to the investigation or self-incriminating. Crime goes down by half if one house regularly snitches, and crime is eliminated if both do.
The expected cost of self-incrimination when volunteering information (with all probabilities worked out) is 3. The cost of unchecked crime in the neighbourhood is 4, applied to each house. The payoffs, then:
- If neither house snitches, payoffs are -4/-4.
- If one house snitches, payoffs are -2/-5 (against the snitch)
- If both houses snitch, payoffs are -3/-3.
This is classic prisoner's dilemma. I thought the general idea was clear enough in my initial post, but at this point the analogy I was making should be impossible to miss.
I don't disagree with your third paragraph. A lawyer will decrease your personal expected negative payoff without compromising the societal benefit of coming forward.
'My point is that the police can't do their job without information, and almost all information given to the police is volunteered by innocent people. Far fewer crimes would be solved if everyone clammed up when the police knocked on their doors, and that'll inevitably lead to more crime.'
Right. So let's just remove the need for a warrant, and revoke the fifth amendment. You have nothing to fear if you have nothing to hide, citizen.
That isn't really fair. I took great care not to say that people should feel compelled to give information, only that we should feel obliged to provide it voluntarily under many situations. (Certainly not all situations, either -- information given in confidence should be inviolable without a warrant, for one thing.)
I didn't mean to say that "if everyone (including guilty people) is honest with the police then guilty people will be caught." That would have been naive. My point is that talking to the police is a prisoners dilemma when considered as a game played only between innocent people.
My point is that the police can't do their job without information, and almost all information given to the police is volunteered by innocent people. Far fewer crimes would be solved if everyone clammed up when the police knocked on their doors, and that'll inevitably lead to more crime.