My prisoner's dilemma

[As Jude kindly corrected me- told you he knows his stuff-, the situation I describe below is actually not so much the Prisoner's dilemma as it is the Diner's dilemma, which is essentially an n-player Prisoner's dilemma. While the fundamental ideas are the same, the dynamics are slightly different.]

So according to classical Prisoner's dilemma theory, when two individuals are faced with the choice to either cooperate or defect and if their only concern is with maximizing their own interest without any concern for the other person's payoff, then the rational decision is to defect (or "betray") even though each person's individual reward would be greater if they cooperated. This is of course a very blunt and naive distillation of what is essentially a very nuanced theory (which if you're interested, you can go read Jude's 60-page prelim paper...) and I bring this up not to provoke some sociological economics debate about self-interest, altruism, or one's commitment to the public good (again, for that, you'd have to go to my husband).

So last week, I found myself standing in line at the taxi-stand, very frustrated. It was 10.15pm and I had been standing in the queue for almost 40 minutes. I was fourth in line and had been fourth in line for the whole of those 40 minutes. The line had not moved. And there was at least 15 people behind me. Since we've been back, Jude and I have made a very conscious decision to take the train more and avoid cabs as much as possible. Between the rising cost of cab fares and the traffic jams you invariably encounter, it just is more cost- and time-efficient to take the train. But on this Friday night, I was tired and not too far from home so I figured the fare wouldn't cost too much. Besides, it looked like cabs were streaming regularly through the taxi-stand so I wouldn't have to wait long either.

But I was wrong. About the wait, at least. During the time I was in line, I could have taken the train and be home and rested. What I wasn't wrong about though, was the number of cabs coming through the taxi-stand. Oh there were cabs alright, just not cabs that were available for street hire. In that 40 minutes, every, and I mean *every* cab that came through was "On Call", i.e. reserved via phone. For an extra $3.80, you can call the cab company, and any cabs near your location will swing by and pick you up, without you having to wait in line at the stand. Now, there is nothing wrong with calling a cab, of course- this service is a godsend in an emergency or when you're late, but something just didn't feel right in that situation. By calling for a cab without standing in line (or while you were standing at the end of a long line), you are essentially depriving someone who has been standing in line- or someone ahead of you in the line- of a cab that otherwise would have come into the stand, available for street hire. Meaning, if I don't call a cab because I'm unwilling to pay that extra surcharge, I am destined to stand in line indefinitely. Think about it, if you were a cab driver in the vicinity of that taxi stand, faced with a choice of picking up someone who calls in (and earning an extra $3.80) and just driving into the taxi-stand and picking up whoever is waiting, what would you do?... Yup, and that's why you end up with hordes of cabs plying the streets waiting for reservations and never driving into cab stands.

[Photo from mr brown who seems to share my sentiments...]

So this is where the prisoner's dilemma comes in. Sort of. If everyone starts calling for cabs- which will evetually make taxi-stands irrelevant- then everyone will inevitably be worse off because 1) you won't be able to flag cabs down on the street; and 2) everyone will have to pay an extra $3.80, driving the ultimate cost of fares up. So much for an affordable public transportation system available to and affordable by all. However, if people refrain from calling for cabs unless there isn't a cab stand nearby and there are no cabs on the street, then even though we will all have to stand in line, the wait won't be long because cabs won't be driving around waiting to pick up customers who call, and are thus forced to have to drive into cab stands instead.

I know this is turning into a really long post, and a rant of sorts, and it probably sounds a little trivial. But it's been on my mind these past couple of days. Jude even tried helping me work this out theoretically over coffee last night. There is no easy solution of course, and it's hard to pin blame on anyone. As rational decision-makers, we can't help but act in ways that are self-interested. But standing in line for that 40 minutes made me appreciate the possibility of a time when self-interest will neither be a primary motivation or an act of first instinct (who knew that aching feet and a frustrated mind inspires such profundity?...) It's kind of like the Joker's social experiment with the two ferries in The Dark Knight- are you willing to give up the security of self-interest for the eventuality of larger social good?