The Enemy of My Enemy
21.01.2025
Alessandro Stringhi (University of Siena); Sara Gil-Gallen (Institute of Cognitive Sciences and Technologies, Italian National Research Council); Andrea Albertazzi (IMT School for Advanced Studies Lucca)
C73, C92, D81
Competition, Cooperation, Prisoner’s Dilemma, Repeated game
This paper studies how competition between groups affects cooperation. In the control condition, pairs of subjects play an indefinitely repeated Prisoner’s Dilemma game without external competition. In the treatment, two pairs compete against each other. No monetary rewards are tied to winning, isolating the bare impact of competition. In the treatment, cooperation increases by 16 percentage points. Strategies estimation shows a shift from selfish strategies (Always Defect) to cooperative ones (Grim Trigger). A theoretical model provides a rationale for the experimental results.
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Suggested citation: A. Stringhi, S. Gil-Gallen, A. Albertazzi, ‘The Enemy of my Enemy’, Nota di Lavoro 03.2025, Milano, Italia: Fondazione Eni Enrico Mattei