Spontaneous Changes in Indefinitely Repeated Prisoner’s Dilemma Games
Prof. Shi QI
Associate Professor of Economics
College of William & Mary
Date: 13 October 2025 (Monday)
Time: 15:00-16:30
Venue: E22-G015
Host: Prof. Jia YUAN, Associate Professor in Business Economics
Abstract
This study investigates spontaneous changes in behavior within indefinitely repeated Prisoner’s Dilemma (IRPD) games, focusing on how teams—rather than individuals—make decisions and adjust strategies over time. Using experimental data with both perfect and imperfect monitoring, we find that spontaneous changes, including unilateral deviations and shifts in initial actions, are frequent, systematic, and persistent, contradicting the view that they are merely random trembles. To uncover the underlying motivations, we analyze within-team chat dialogues with a novel coding methodology that combines human coders and large language models (LLMs). This approach reveals that teams deviate from equilibrium strategies for reasons such as leading by example, experimenting with payoffs, or exploiting trust, with patterns varying across monitoring conditions. Our dynamic modeling shows that team play promotes faster learning, more stable cooperation, and strategy improvisation, providing new insights into the mechanisms of cooperation and highlighting the value of AI-assisted qualitative analysis in experimental economics.
Speaker
Prof. Shi QI is an Associate Professor of Economics at the College of William & Mary. His research focuses on industrial organization, industry productivity, regulation and policy, and organizational behavior, with a particular interest in how market structure and policy shape firm behavior and performance. His publications appear in leading journals such as the RAND Journal of Economics, Management Science, and the American Economic Journals.
All are welcome!
