Prisoners’ dilemmas are more serious problems in theory than in practice. But social institutions, and our own instincts, produce more co-operative behaviour than crude models of rational economic man would allow.
MRSA, the hospital “superbug” that has grabbed headlines in the UK, is an infection that resists most antibiotics. Prescriptions for antibiotics tell the patient to complete the course. You will feel better when most of the organisms causing infection have been killed. But those organisms that remain are, necessarily, more than averagely virulent and more than averagely drug resistant. If they are allowed to survive, they multiply, and this is how superbugs develop. The main benefit from completing a course of antibiotics is not to the patient, but to the invalid, the old and the very young, who are vulnerable to drug-resistant infection.
The patient information leaflet that came with the antibiotic I took recently does not explain this. It warns that if you do not complete the course your illness might recur. This is true, but not the main issue. The manufacturer appears to believe that an appeal to self-interest will be more persuasive than an appeal to public spirit. My own reaction was the opposite. I used to stop the tablets as soon as I had recovered. Now I know the rationale, I take them conscientiously.
Antibiotic use illustrates a “prisoners’ dilemma”, in which individually rational actions produce outcomes that are bad for everyone. Yet prisoners’ dilemmas are more serious problems in theory than in practice. Social institutions, and our own instincts, produce more co-operative behaviour than crude models of rational economic man would allow – if they are given a supportive environment.
For instance, I still turn right out of the car park at the commuter station I use. In England, where people drive on the left, you must cross the flow of traffic to turn right. It takes longer, especially at busy times, to turn right than to turn left. But at this station, it is still slightly quicker, on average, for someone whose destination is on the right to do this than to pursue the alternative of driving 200 yards to turn at a roundabout.
This is the decision you face when you reach the front of the queue. If everyone turned left, the queue would last no more than five minutes and almost everyone – including those who wanted to turn right – would get home more quickly. It can take 15 or 20 minutes to clear the traffic from a busy commuter train and, as soon as it arrives, tired travellers can be seen sprinting to be first to their cars.
I suspect a notice saying “Please don’t turn right at busy times” would solve the problem. In fact, if there were a means of signalling to my fellow commuters that, although I really wanted to turn right, I was turning left to assist those behind, that would probably do the trick. People who gave that signal would return home with a warm glow, and people who indicated they were turning right would be hooted at by those behind.
Economists and biologists used to believe that selfish behaviour was inevitable because natural selection would favour it, but now know that this is not necessarily true. Co-operative behaviour flourishes when it is reciprocated, and the station car park clears slowly because there is no means for the public-spirited to demonstrate that they are public-spirited.
But generalised reciprocity is usually enough. We give directions to strangers asking the way, expecting that different strangers will do the same for us. The selfish gene is not the same as a gene for selfishness, and a gene for selfishness is often less adaptive than a gene to co-operate with people who are themselves inclined to co-operate. I think many people would accept the admonition to complete the course of antibiotics if they understood the reason.
But, as John Maynard Keynes famously observed, practical men are usually the slaves of some defunct economist. Patient information leaflets are written and traffic regulations devised on the theory that now widely underpins both public and business policy: people will respond only to incentives directly aimed at them.
But as shareholders who approved executive incentive programmes discovered to their cost, if you design institutions on the assumption that behaviour is naturally self-interested, self-interested behaviour will follow. And so we have superbugs, congestion at commuter stations – and increasingly greedy corporate executives.