Interactive simulator

Game Theory Payoff Matrix Simulator

Two suspects are interrogated separately: confess or stay silent. This simulator lets you edit every payoff in the matrix, then highlights the Nash equilibrium — the cell where neither player can do better by changing strategy alone. The classic dilemma shows both confessing (D,D) as the equilibrium even though mutual silence would pay better, illustrating why individual incentives can produce collectively poor outcomes.

Prisoner's Dilemma Lab

Edit the payoffs, pick both strategies, find the Nash equilibrium

R — mutual cooperation

T — temptation

S — sucker

P — mutual defection

Payoff matrix — each cell shows (You, Opponent)
	Opp: Cooperate	Opp: Defect
You: Cooperate	(3, 3)	(0, 5)
You: Defect	(5, 0)	(1, 1) ★ NASH EQUILIBRIUM

Your move:

Opponent's move:

You earn 3, opponent earns 3

This is not a Nash equilibrium — at least one player would deviate.

How to read it

A cell is a Nash equilibrium when no player can improve by switching alone. With the classic payoffs (T=5, R=3, P=1, S=0), defecting always pays more no matter what the opponent does — so (Defect, Defect) is the unique equilibrium, even though both players would earn more at (Cooperate, Cooperate).

How to use it

Edit any payoff values in the matrix.
Press 'Find Nash equilibrium' to highlight equilibrium cells.
Try making cooperation pay better and watch the equilibrium move.
Compare the equilibrium with the socially best outcome.

What you will learn

Define a Nash equilibrium.
Explain the prisoner's dilemma logic.
Apply game theory to pricing, advertising, or arms races.

Model notes

This is a one-shot simultaneous game with ordinal payoffs; repeated games, mixed strategies, and communication are not modeled. Payoffs are illustrative, not measured.