Game theoryClassroom · multi-user
Ultimatum Game — Fairness & Rejection
Paired up, a Proposer splits 100 points and a Responder accepts (both paid) or rejects (both get nothing). Watch fairness beat cold self-interest.
You’ll learn: See why people reject 'free' money when a split feels unfair — contradicting the self-interested prediction that any positive offer is accepted.
- Fairness & reciprocity
- Inequity aversion
- Costly punishment
- Subgame-perfect equilibrium vs. behavior
Teacher guide
Students will learn to
- Experience both sides of a take-it-or-leave-it bargain.
- Contrast the game-theory prediction (offer the minimum, always accept) with what real people do.
- Connect rejections of unfair offers to fairness norms and inequity aversion.
Before the session — ask
- If someone offered you 5 of 100 points — free money — would you take it? Why or why not?
- What split would a purely self-interested Proposer offer, assuming a purely self-interested Responder?
After the session — discuss
- What was the most common offer, and how many low offers were rejected?
- Why might a Responder give up real points to reject an unfair split?
- How does this complicate the assumption that people only maximize their own payoff?
Timing
- Briefing & pairing3–5 min
- Offer & decide4–6 min
- Reveal & discussion8–10 min
Run it with your class
Students join with a code or QR — no account needed. Teachers start a session from the dashboard.