I must begin this blog post with a confession. I have never been into game theory, and although I did take some undergraduate courses in it, I’ve always struggled to understand it all. But while I was somewhat uneasy about game theory (or at least parts of it), I couldn’t express the reasons for my reservations. It was more of a feeling.
From these days, I still remember a conversation I had with a fellow undergrad (perhaps she had also recently graduated) about game theory. She was rather fond of it and gave nice arguments about why it was helpful and good. Back then, one of the criticisms I voiced was that game theory struggled to explain cooperation, or so I thought.
What made me wonder was how exactly game theory could explain cooperation if it assumes that people are selfish and maximize their (narrowly construed) expected utility. She responded, “Oh, that’s not a big deal. Once you assume iterated games, it is rational to cooperate.” In and of itself, the answer seemed convincing. After all, if we anticipate seeing each other more than once, we should adjust our behaviour accordingly. And then it may really be “rational” to cooperate and not defect. So, that day, I left it at that. But I couldn’t quite shake off a feeling of uneasiness with that solution.
Things changed when I read Joe Henrich’s monumental work The WEIRDest People in the World, published in 2020. Henrich does many things in this tract, but he also touches on life in prehistoric times. And in an intriguing passage, he reflects on interactions between humans. Henrich (p. 303) writes:
WEIRD people tend to think that trade is straightforward: we have wild yams and you have fish; let’s swap some yams for some fish. Easy. But, this is misguided. Imagine trying to barter yams for fish in the hunter-gatherer world described by William Buckley in Australia. In this world, other groups were often hostile, and strangers were frequently killed on sight. To conceal their nocturnal locations, bands erected low sod fences around their campfires so they couldn’t be spotted from a distance. If I showed up at your campfire with some yams to trade, why wouldn’t you just kill me and take them? Or you might have thought we are only offering our toxic yams, which would slowly poison you and your band. Under such conditions, which were probably common over our species’ evolutionary history, it’s difficult to see how smoothly flowing trade could ever emerge.
If Henrich is right, then we cannot simply assume that there will be a second round, not to speak of games with infinite rounds. Indeed, perhaps the usual kind of interaction would be the attempt to kill each other. Or the two would refrain from interacting with each other at all.
But if, for this or that reason, there were a second round, that would presuppose that there was a first round of interaction and that it had been peaceful. For example, we had exchanged yams for fish. To the least, we did not kill each other, either with our spears or poisoned yams. But this is, or at least is very close to, cooperation in the sense of peaceful, coordinated, and reciprocal interaction—if only in a very crude and basic form.
Following Henrich, then, the sheer fact that there is a second round of interaction, that is, that our game started at all, and if it started that it does not end after the first instance (because either I killed you or you killed me, or to the least, the interaction was so distasteful that none of us sees any reason to interact with each other again), requires a basic level of cooperation.
But this implies that game theorists’ assumption of iterated games to demonstrate that cooperation is possible and does, indeed, follow in game-theoretic scenarios, is a petitio. They already assume that people’s interaction will be characterized by basic cooperation or at least peacefulness when they assume that people will face iterated and even infinitely iterated games, that is, do not kill each other at first sight. Therefore, game theory covertly assumes cooperative and peaceful interaction to explain cooperation. And that’s problematic.
I want to come back to the remarks I made at the beginning of this piece. I am by no means an expert in the field of game theory. I am just an outsider who puts forward his thoughts about game theory—a critic who, surely, may miss the forest for the trees. But perhaps commenters on this blog can show me where my reasoning goes wrong. Or, perhaps, my critique has something to it, and game theory has some work to do.
Max Molden is a PhD student at the University of Hamburg. He has worked with European Students for Liberty and Prometheus – Das Freiheitsinstitut. He regularly publishes at Der Freydenker.
