Interactive module
Prisoner’s Dilemma
See why individually sensible choices can make everyone worse off.
Rule ledger
caseTwo roommates are accused of stealing takeout and must stay silent or betray each other.
rule
Defect dominates because u(defect, s_other) > u(cooperate, s_other)questionWhen one strategy changes alone, whose payoff or fairness changes first?
Takeout Interrogation
TakeoutGroup projectsPrice discipline
Roommate A
A / B
Cooperate
Defect
Cooperate
-1, -1
-5, 0
Defect
0, -5
-3, -3
Trust score58
Roommate B
A action
B action
A payoff
-5
B payoff
0
1
Round 1: choose actions
How to read this result
Defection can look safer in a single round, but mutual defection lowers the shared outcome. The trust score shows how future relationships can change today's incentives.Formula
Defect dominates because u(defect, s_other) > u(cooperate, s_other)Betrayal is individually safer, but mutual silence creates the best shared outcome.
Step-by-step Explanation
Scenario
Two roommates are accused of stealing takeout and must stay silent or betray each other.
Why This Matters
Many trust problems in teams, markets, and politics have this same shape.
Beginner-Friendly Summary
Rational self-protection can destroy value unless repetition, norms, or trust change incentives.
Try changing the strategy and watch which result changes first.