Economic Theory

, Volume 68, Issue 4, pp 827–844 | Cite as

Frequency of interaction, communication and collusion: an experiment

  • Maria BigoniEmail author
  • Jan Potters
  • Giancarlo Spagnolo
Research Article


The frequency of interaction facilitates collusion by reducing gains from defection. Theory has shown that under imperfect monitoring flexibility may hinder cooperation by inducing punishment after too few noisy signals, making collusion impossible in many environments (Sannikov and Skrzypacz in Am Econ Rev 97:1794–1823, 2007). The interplay of these forces should generate an inverse U-shaped effect of flexibility on collusion. We test for the first time these theoretical predictions—central to antitrust policy—in a laboratory experiment featuring an indefinitely repeated Cournot duopoly, with different degrees of flexibility. Results turn out to depend crucially on whether subjects can communicate with each other at the beginning of a supergame (explicit collusion) or not (tacit collusion). Without communication, the incidence of collusion is low throughout and not significantly related to flexibility; when subjects are allowed to communicate, collusion is more common throughout and significantly more frequent in the treatment with intermediate flexibility than in the treatments with low or high flexibility.


Cartels Cournot oligopoly Flexibility Imperfect monitoring Repeated games 

JEL Classification

C73 C92 D43 L13 L14 



We wish to thank the editor, the associate editor and two anonymous reviewers for their helpful comments and suggestions. We also thank Andrzej Skrzypacz for his precious advice, and Charles Angelucci, Jeff Butler, Gabriele Camera, Martin Dufwenberg, Christoph Engel, Ernst Fehr, Tobias Klein, Wieland Mueller, Karl Schlag, Jean Robert Tyran and participants at the European ESA Meeting in Innsbruck, the M-BEES Workshop in Maastricht, the Industrial Organization Workshop in Otranto, the CRESSE conference in Rhodes, the EIEF-Bologna-Bocconi IO Workshop, the ESRC London Experimental Workshop (LEW), the Amsterdam Symposium on Behavioral and Experimental Economics (ABEE) and seminars at Humboldt University Berlin, the Stockholm School of Economics, Erasmus University Rotterdam, Tilburg University, University of California Santa Cruz, IFN Stockholm, the MPI for Collective Goods in Bonn, the Technische Universität Berlin, the University of Vienna and the University of Aix-Marseille for valuable comments.

Supplementary material

199_2018_1146_MOESM1_ESM.pdf (277 kb)
Supplementary material 1 (pdf 276 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of EconomicsUniversity of BolognaBolognaItaly
  2. 2.IZABonnGermany
  3. 3.Department of Economics and CentERTilburg UniversityTilburgThe Netherlands
  4. 4.SITE-Stockholm School of EconomicsStockholmSweden
  5. 5.Department of Economics and FinanceTor Vergata UniversityRomeItaly
  6. 6.Einaudi Institute for Economics and FinanceRomeItaly
  7. 7.Centre for Economic Policy Research (CEPR)LondonUK

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