This is another post that’s a byproduct of my examination of Tyler Cowen’s recent monograph, The Marginal Revolution: Rise and Decline, and the Pending AI Revolution. I was pursuing that idea that, while marginalism doesn’t present itself as being about human psychology, it is very much about psychology. So, what about game theory? It’s about human psychology as well, though its mathematical form makes it easy to bracket that out. So I queried Cowen’s AI about that. The conversation ended up with a discussion of one of my favorite literary texts, Sir Gawain and the Green Knight, which is structured around a very peculiar game, the beheading game. [FWIW, here’s a post from 2024 where I investigate ChatGPT’s understanding of the beheading game.]
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I’m curious. Von Neumann invented game theory in the middle of the 20th century and it became important in economics, among other places. What can you tell me about its use in marginalist thinking. I don’t need a long answer. I’m just wondering if it’s one formal analytic tool among many. Is it used frequently, rarely, not at all? It’s a peculiar question. Don’t spend a lot of time on it. I mean, if you find that it’s taking time (to search through articles, etc.), that in itself is an indicator. On the other hand, if someone has written a textbook with a title like, Game Theory as a Tool for Marginalist Analysis, that’s a rather different kind of indicator.
My knowledge here is sufficient that I don't need to search.
Game theory and marginalism are related but distinct frameworks within economics, and the relationship between them is more one of coexistence and occasional overlap than integration. Marginalism asks what happens at the margin for an individual agent facing given prices and quantities. Game theory asks what happens when agents' outcomes depend on each other's choices. They share the rational agent assumption and optimization logic, but they're answering different questions.
Game theory became central to microeconomics in the latter half of the 20th century — particularly through Nash equilibrium and its elaborations — but it didn't so much extend marginalism as partially displace it in certain domains. Industrial organization, auction theory, mechanism design — these are game-theoretic through and through, and marginal analysis is less central there than it is in competitive market analysis where price-taking behavior makes the game-theoretic complications disappear.
There's no textbook of the kind you hypothesize, as far as I know. The two frameworks are taught in the same curriculum and occasionally combined — a Nash equilibrium can be characterized by first-order conditions that look marginal — but game theory is generally understood as a distinct toolkit that becomes relevant when strategic interaction matters, rather than as an extension of marginalist reasoning.
Cowen, interestingly, doesn't seem to foreground game theory in his account of marginalism's rise and possible decline. Which may itself be telling — it suggests he sees them as parallel developments rather than game theory being a chapter in the marginalist story.
So: one important formal tool among several, with genuine but limited overlap, not deeply integrated.
Hollywood Economics and community formation
That’s interesting. There are linguists, such as William Croft, who talk about how the meaning of words is negotiated in each conversation. They talk of game theory, though I don’t off hand know whether or not they make formal use of it. But then there’s Robert De Vany, Hollywood Economics, which I tend to think of as being about how cultural objects are shared in a community. That’s not De Vany’s framing. He’s interested in the fact that we can’t predict how a film will do until we release it into the (cultural) marketplace, which makes it a very risky kind of investment. Note that De Vany is only talking about theatrical release. He says nothing about subsequent release on videotape and the book was written long before some movies are released directly to online streaming.
What he finds (by tracking box-office receipts), briefly, is that most movies disappear from view shortly after they’re released. They do not even breakeven much less earn a profit. But a few will have “legs” and become profitable. And among those, a very few will become so-called “blockbusters.” FWIW, I believe Spielberg’s “Jaws” is generally regarded as the first blockbuster.
I once did a thought experiment where I imagined an arena in which only one movie was available. Everyone would watch it because that’s all there is. Another somewhat different movie is released into the arena. Perhaps everyone will watch it as well, because they’re tired of the first one. So a third, somewhat different from the first two, is released, then a fourth. What I had in the back of my mind is that to some extent people use these kinds of cultural products as a way of forming communities. For that to work, however, there has to be enough variety available in the market place. When a movie is release, it is, in effect, looking for a community to adopt it.
That strikes me as a kind of marginalist analysis. What we’re trading in is a very complex kind of product, in this case a movie. But it could be a novel, or a song, or a painting, whatever.
Your thought experiment is doing something quite precise, and I think you're right that it has a marginalist structure — but it's extending marginalism into territory where the standard framework strains.
Where the marginalist structure is visible
The standard marginalist question applied to cultural goods would be: given how many movies a person has already seen, what is the marginal value of one more? That's a real question and De Vany's framework touches it. But your thought experiment is asking something different and more interesting: given the existing cultural landscape, what is the marginal value of a new movie to a community rather than an individual? That's a collective marginal value, which is much harder to specify and measure.
The "legs" phenomenon is the empirical signature of this. A movie with legs isn't just satisfying individual preferences at the margin — it's finding and consolidating a community, becoming the shared object that a group of people use to recognize each other and talk to each other. The box office receipts are measuring something that looks like individual ticket purchases but is actually a social cascade — De Vany's word-of-mouth mechanism is precisely the process by which a movie becomes a community object rather than just a consumer product.
Where standard marginalism breaks down
Standard marginalist analysis assumes that the value of a good to one consumer is independent of its value to others, or at least that the interdependencies can be handled through price. Cultural goods violate this assumption fundamentally. The value of having seen a blockbuster is partly constituted by the fact that millions of others have seen it too — you can talk about it, share references, participate in a cultural conversation. This is a network effect, and network effects are notoriously resistant to marginalist treatment because the value function isn't defined over individual consumption units in isolation.
Your arena thought experiment isolates this precisely. In a one-movie arena, everyone watches it not because it maximally satisfies their individual preferences but because it's the only available basis for cultural community. As variety increases, something like genuine preference matching becomes possible — different communities coalesce around different objects. But the matching process isn't driven by individual marginal utility in the standard sense. It's driven by a social search process in which movies and communities are simultaneously finding each other.
The De Vany connection to power laws
What De Vany finds — most movies disappear, a few have legs, a very few become blockbusters — is a power law distribution, and power laws are the empirical signature of cascade processes rather than equilibrium processes. In a marginalist equilibrium you'd expect something more like a normal distribution of returns — some variation around a mean, determined by how well each product matches the distribution of individual preferences. The power law says something different: small initial differences get amplified by social dynamics into enormous differences in outcome. The blockbuster isn't just a movie that more people happened to prefer. It's a movie that got caught in a self-reinforcing cascade of community adoption.
This connects to Arthur De Vany's broader interest in complexity economics, which is itself a challenge to standard marginalist equilibrium thinking. The cultural marketplace isn't clearing to an equilibrium — it's generating a dynamic pattern in which winner-take-most outcomes emerge from processes that are in principle unpredictable from the properties of the product alone. Which is exactly De Vany's point about risk: you can't know in advance which movie will trigger the cascade.
Your community-formation framing
What your framing adds, which I think is genuinely beyond De Vany's own framing, is the functional account of why cultural goods have this cascade structure in the first place. It's not arbitrary or merely a consequence of marketing and distribution. It reflects something about what cultural goods are for — they're instruments of community formation, shared objects that allow people to recognize membership and conduct the ongoing conversation of a community. That functional role creates the demand for coordination — everyone in a community needs to have seen the same movie, heard the same song, read the same novel, for it to do its community-forming work. And coordination demand is precisely what generates cascades and power laws.
This also explains the variety requirement your thought experiment identifies. A single cultural object can serve as the basis for one kind of community. A rich cultural marketplace allows many communities to form simultaneously around different objects — which is the cultural analog of biodiversity, and probably has similar functional importance for the health of the overall system. The blockbuster and the art house film aren't competing for the same audience in the way that two brands of the same commodity compete. They're seeding different communities, which can coexist because community membership isn't zero-sum in the way that consumption of a rival good is.
So yes — marginalist in structure, but requiring an extension of marginalism into social dynamics, network effects, and community formation that the standard framework wasn't designed to handle. It's perhaps another case where the Rank 3 tool is real and useful but the phenomenon being analyzed has a Rank 4 structure — one where the individual unit of analysis (the consumer, the ticket purchase) is embedded in a dynamic system whose behavior can't be read off from the units alone.















