ZBC
Zombie Betrayal Coefficient, 0–100, from flaw weight, scenario, and seeded jitter.
Zombie Apocalypse Betrayal Index: Who in Your Crew Trades You for a Can of Beans?
Choose a crew type to reveal your squad Judas and betrayal hour in seconds — or fill real names and refine flaws later.
Survival math: game theory and the prisoner’s dilemma in a catastrophe
Pop-culture zombie nights in U.S. dorms and living rooms are jokes about loyalty. Underneath sits the same formal problem John Nash and John von Neumann framed for scarce resources: when does cooperation stop being an equilibrium?
In a repeated prisoner’s dilemma with a known end (the last can of beans), Nash equilibrium drifts from cooperate toward defect. Early hours still look like solidarity — shared barricades, shared watch. As the horizon shortens, the expected payoff of defecting rises. That is the Betrayal Coefficient’s narrative skeleton: flaws raise the temptation payoff; harder scenarios (sprinters, six-month siege) compress the timeline.
leaderZBC = 22 + round(ego × 0.35) + scenMod + jitter(±8)
friendZBC = flawWeight + scenMod + jitter(±8)
T = max(4, round(120 − ZBC × 1.1)) // hours since outbreak
Judas = argmax(ZBC across squad)
Victim ≈ argmin(ego − empathy)Tragedy of the commons shows up as the bunker pantry: medicine and calories are shared goods until someone starts a private stash. Isolation studies from polar winters and long-duration confinement analogs (including Mars-500-style protocols) keep rediscovering the same arc — high early cohesion, then factioning around ration fairness. The calculator is entertainment, but the phases map onto that literature.
Psychological roles in a survival group and survival odds
Background table — mean survival days and alliance % are illustrative, not the survival % matrix from the simulator.
| Group archetype | Main asset | Critical flaw | Alliance reliability | Mean survival time |
|---|---|---|---|---|
| Utilitarian leader (alpha) | Hard decisions under pressure | Tendency to cut weak links | Medium (50%) | 180 days |
| Moral compass (empath) | Keeps group psyche intact | Paralysis when violence is required | Very high (90%) | 35 days |
| Tech / medic specialist | Life-saving unique knowledge | Low combat fitness; needs protection | High (75%) | 140 days |
| Resource opportunist | Strong self-preservation | Zero loyalty when stocks < 3 days | Extremely low (10%) | 95 days |
| Reactive panicker | Fast threat detection | Noise + ally distraction | Low (25%) | 12 days |
Anatomy of betrayal: how alliances actually fall apart
- Shock & solidarity (0–48 h). Apparent unity, crisis altruism, joint base security.
- Rationing & suspicion (days 3–14). First accusations of hidden calories; cliques form.
- Sharp resource asymmetry (days 15–30). Empathy for the injured collapses; they are reframed as “extra calorie consumers.”
- Open betrayal. Night exit with the stash, transport sabotage, hostile takeover of supplies.
Press kit: naming the Judas in America’s dorm and group chats
Editors packing Halloween, campus, or disaster-prep packages can treat the Zombie Betrayal Index as a playful wrapper on game-theory loyalty: a named Judas, a betrayal hour on a 0–120 hour axis, and a four-person survival matrix. Pair a screenshot with a dorm or neighborhood group-chat survey — “who would steal the last flashlight?” — for a shareable social piece that still cites Nash, commons tragedies, and isolation research.
Quotable box
“An ideal survival cell is about four to six people: enough specialists for security, supply, and medicine, small enough that rationing stays controllable and mutiny stays rare. Pure selfishness wins only the first days; over a longer horizon, groups that practice reciprocal altruism — tit-for-tat — outlast loners. Betrayal itself has phases: shock solidarity in the first 48 hours, ration suspicion by week two, then open defect once the pantry looks finite.” — CalcBoxer Zombie Betrayal Index press notes
- Ideal group size: 4–6 people (role coverage without runaway mutiny risk).
- Best long-run strategy: tit-for-tat / reciprocal altruism — not pure egoism.
- Betrayal phases: 0–48 h solidarity → days 3–14 suspicion → days 15–30 asymmetry → open betrayal.
- Story hook: named Judas + betrayal hour + optional “leave Judas behind” survival delta.
FAQ — survival psychology in a group
What is the ideal group size for surviving a catastrophe?
Anthropological and military research points to an optimal tactical group of about 4 to 6 people. That size supports specialist role coverage (security, supply, medicine) while keeping food rationing controllable and mutiny risk low.
Is pure selfishness the best survival strategy?
No. Pure egoism works only in the first days. Over longer horizons, solo actors fail because they cannot maintain continuous watch during sleep and lack care for minor infections. Highest long-run survival appears in groups practicing reciprocal altruism (tit-for-tat).
How do you spot that a group member is planning betrayal?
Early signs include packing personal gear into one grab-and-go bag, refusing paired night watches, withdrawing from long-term planning talk, and avoiding eye contact during food distribution.
Glossary
Betrayal hour (T)
Hours after outbreak when that person’s alliance reliability collapses in the model.
Squad Judas
Highest ZBC in the four-person crew.
Tit-for-tat
Reciprocal altruism strategy that outperforms pure egoism in long-horizon survival games.
Sources
- Wikipedia: Nash equilibrium
- Wikipedia: Prisoner's dilemma
- Wikipedia: Tragedy of the commons
- Wikipedia: Mars-500
Page updated October 16, 2026.