You Better Play 7: Mutual versus Common Knowledge of Advice in a Weak-Link Experiment

29 Pages Posted: 16 Jan 2012

See all articles by Giovanna Devetag

Giovanna Devetag

Luiss Guido Carli

Hykel Hosni

University of Milan - Department of Philosophy

Giacomo Sillari

Luiss Guido Carli

Date Written: January 16, 2012

Abstract

This paper presents the results of an experiment on mutual versus common knowledge of advice in a two-player weak-link game with random matching. Our experimental subjects play in pairs for thirteen rounds. After a brief learning phase common to all treatments, we vary the knowledge levels associated with external advice given in the form of a suggestion to pick the strategy supporting the payoff-dominant equilibrium. In the mutual knowledge of level 1 treatment, the suggestion appears on every subject's monitor at the beginning of every round, with no common knowledge that everybody sees the same suggestion. In the mutual knowledge of level 2 treatment, the same suggestion appears on each subject's monitor, accompanied by the request to "send" the suggestion to the partner in the round, followed by a notification that the message has been read. Finally, in the common knowledge treatment, the suggestion is read aloud by the experimenter at the end of the learning phase. Our results are somewhat surprising and can be summarized as follows: in all our treatments both the choice of the efficiency-inducing action and the percentage of efficient equilibrium play are higher with respect to the control treatment, revealing that even a condition as weak as mutual knowledge of level 1 is sufficient to significantly increase the salience of the efficient equilibrium with respect to the absence of advice. Furthermore, and contrary to our hypothesis, mutual knowledge of level 2 (as the one occurring in our "message" treatment) induces successful coordination more frequently than common knowledge.

Keywords: Coordination games, experimental philosophy, epistemic attitudes, weak-link game, conventions

JEL Classification: D01, D83

Suggested Citation

Devetag, Giovanna and Hosni, Hykel and Sillari, Giacomo, You Better Play 7: Mutual versus Common Knowledge of Advice in a Weak-Link Experiment (January 16, 2012). Available at SSRN: https://ssrn.com/abstract=1986203 or http://dx.doi.org/10.2139/ssrn.1986203

Giovanna Devetag (Contact Author)

Luiss Guido Carli ( email )

Via Salvini 2
Roma, 00197
Italy

Hykel Hosni

University of Milan - Department of Philosophy ( email )

via festa del perdono 7
Milan, 7-20122
Italy

Giacomo Sillari

Luiss Guido Carli ( email )

United States

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