Ultimatum Game
Proposer offers a split; responder can accept or reject. Rejection yields zero for both.
Frequently Asked Questions
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What does the game measure?
Fairness preferences and strategic behavior in social bargaining.
Why would anyone reject free money?
Because most people weight fairness as well as payoff: rejecting a stingy offer costs points but punishes unfairness — inequity aversion in action.
What offers are typical?
Proposers across cultures commonly offer 30-50% of the pot, and offers below roughly 30% are rejected at substantial rates, though rejection rates vary across populations.
What does this say about economic rationality?
That preferences are social: utility includes fairness, not only monetary payoff — a foundational result of behavioral game theory.
Am I playing against a real person?
No. Opponent choices in this demo are generated by a simple simulated strategy (not a real player), so results illustrate the payoff structure rather than measure interpersonal behavior.
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About the Ultimatum Game
Economic Behavior
The Ultimatum Game demonstrates the tension between self-interest and fairness norms. Proposers typically offer 40-50% of the stake, and responders typically reject offers below 20-30%. Rejections are economically irrational but psychologically meaningful — people would rather punish unfairness than accept a small gain.
Neuroscience of Fairness
Brain imaging studies show that unfair offers activate the anterior insula (associated with disgust) and dorsolateral prefrontal cortex (involved in decision-making). The willingness to reject correlates with insula activation — it's not just a calculation, it's an emotional reaction.
Cross-Cultural Findings
While the general pattern holds worldwide, average offers and rejection thresholds vary by culture and economic context. Studies in small-scale societies show both higher offers and higher rejection rates than typical Western samples, challenging assumptions about universal economic rationality.
References
- Güth, W., Schmittberger, R., & Schwarze, B. (1982). An experimental analysis of ultimatum bargaining. Journal of Economic Behavior & Organization, 3(4), 367-388. 10.1016/0167-2681(82)90011-7
- Forsythe, R., Horowitz, J. L., Savin, N. E., & Sefton, M. (1994). Fairness in simple bargaining experiments. Games and Economic Behavior, 6(3), 347-369. 10.1006/game.1994.1021
- Camerer, C. F., & Thaler, R. H. (1995). Anomalies: Ultimatums, dictators and manners. Journal of Economic Perspectives, 9(2), 209-219. 10.1257/jep.9.2.209
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About This Experiment
This experiment is an educational adaptation for demonstration purposes. It is not a clinical diagnostic tool. Results reflect your performance in this specific session and should not be interpreted as an assessment of your cognitive abilities.
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