Cases on the pattern map
Real cases placed on the three patterns (battle line, stag hunt, chicken). Many sit cleanly in one pattern; thirteen fit two or three, because the pattern is in the payoffs and payoffs move.
Cases on the pattern map
How real cases sort into the three patterns of Patterns of collective action. Names: battle line (Prisoner's Dilemma), stag hunt (assurance game; see Stag hunt), chicken (Volunteer's dilemma; the two-player form is Chicken (game)). The fourth cell, no problem, is where cooperating pays anyway.
The map is built from two questions (Greed and fear):
- Greed: if you pull your weight, do I gain by slacking?
- Fear: if I pull mine alone, do I lose?
Clean cases are written inside their cell. The numbered cases fit more than one pattern: a dot on a border fits both cells, the dot in the middle fits all three, and an outlined dot is the same case in a second cell. The dashed diagonal joins the stag hunt and chicken: cases on it fit both, mostly because of a many-player threshold. The order of dots along a border means nothing.
Clean cases
| Pattern | Taking (restraint) | Building (contribution) |
|---|---|---|
| Battle line | Newfoundland cod; Moloch and races to the bottom | Open source, research, the public-goods experiment |
| Stag hunt | Northern Rock bank run | Protests and revolutions; the union drive in Norma Rae; the Potemkin mutiny |
| Chicken | Brinkmanship; Dr. Strangelove; who gets the best fishing sites at Alanya, Turkey (Ostrom) | A person collapses in the street |
| No problem | Probably leaded petrol (each country gains from its own phase-out) | Meerkat sentinels |
Cases that fit more than one pattern
Thirteen cases fit two patterns or more. The last column says what moves them between patterns.
| Case | Patterns | Taking or building | What moves it |
|---|---|---|---|
| Hoplite battle line | Battle line / stag hunt | Building | Each man gains by easing back (battle line), but the line holds only if enough stand (stag hunt). Krentz's casualty ratio suggests a threshold. |
| Herds scatter; buffalo turn on the lions | Battle line / stag hunt | Building | Group defence works only if enough stand. |
| Anglo-German naval race (before 1914) | Battle line / stag hunt | Taking | Whether each side wants a bigger navy anyway (battle line) or builds only because it fears the other's (stag hunt: the security dilemma). |
| Limited Test Ban Treaty | Battle line / stag hunt | Taking | As the naval race. Verification set what could be banned. |
| Heartbleed and OpenSSL (xkcd 2347) | Battle line / chicken | Building | Many small users, each with a small benefit: battle line. One big firm that gains enough to fund it alone: chicken. After 2014 big firms funded it, possibly a case of one big player solving it (not yet checked). |
| Wikipedia and the open source maintainer | No problem / battle line / chicken | Building | Many small edits are worth making for their own sake (no problem). Maintaining the core is not (battle line), unless one party picks it up (chicken). |
| The Great Stink (London, 1858) | Battle line, then no problem | Building | Those who could fix the sewers didn't bear the cost until the smell reached Parliament, which then gained enough to act alone. Partly a Principal-agent problem. |
| Playground bystanders | Stag hunt / chicken | Building | "We'd all have stood up if we knew the others would" is a stag hunt. "One person telling the head teacher is enough" is chicken. |
| Plataean breakout (428 BC) | Stag hunt / chicken | n/a | Enough must attempt it for it to work (stag hunt); too many makes it riskier. |
| Liberum veto | Stag hunt / chicken | n/a | Any one noble could block the Polish parliament, so each hold-out plays chicken. Needing every vote makes it a stag hunt where the least willing member decides (a weakest-link game). |
| Climate | Battle line / stag hunt or chicken | Taking | Cutting emissions with a smooth cost is a battle line. A known tipping point turns it into a stag hunt or chicken (Taylor's lake that dies past a pollution threshold is chicken; Barrett's argument for a stag hunt is not yet checked). |
| Balinese subak and water temples | Coordination / battle line | Both | Synchronised planting is pure coordination. Sharing water between upstream and downstream is a battle line (Lansing; not yet checked). |
| Frontier AI race | Battle line / stag hunt / chicken | Both | All three, depending on whether labs think racing pays (battle line), would slow if others did (stag hunt), or are waiting for someone else to pause (chicken). |
What the doubles have in common
Almost all are one of two kinds:
- Many-player threshold cases. Below the threshold it is a stag hunt: nobody wants to be the only one. Above it each would rather someone else made up the numbers, which is chicken (Taylor, The Possibility of Cooperation, 1987, pp. 41–43). On the map they sit between those two cells, crossing both lines.
- Cases whose payoffs change with a parameter: open or limited access, an unseen or a salient disaster, one big player or none. Heckathorn ("The Dynamics and Dilemmas of Collective Action", 1996, p. 257) and Ostrom (Governing the Commons, 1990, pp. 46–48) both note that small changes in parameters change the game.
The pattern is in the payoffs, and payoffs move. That is also how fixes work: a fine removes greed, a refund guarantee removes fear, and each moves a case towards "no problem".
Cases that don't fit
- Not a dilemma: meerkat sentinels, probably leaded petrol (both "no problem").
- Not a payoff structure: Twelve Angry Men (an information cascade); the Aral Sea (a central planning decision); the Ik and the Donner Party (social breakdown); Jaws (agency: the mayor).
- Two parties, not a group: vampire bats, cleaner fish, acacia ants. These are bilateral exchange; reciprocity and reputation are the remedies.
- Pattern fits, taking or building doesn't: the liberum veto, and the two-party cases above.
Full working, with sources and open checks: docs/plans/2026-10-29-typology-notes.md (KR4.2).
