Cooperation without coordination: signaling, types and tacit collusion in laboratory oligopolies

We study the effects of price signaling activity and underlying propensities to cooperate on tacit collusion in posted offer markets. The primary experiment consists of an extensively repeated baseline sequence and a 'forecast' sequence that adds to the baseline a forecasting game that allows identification of signaling intentions. Forecast sequence results indicate that signaling intentions differ considerably from those that are counted under a standard signal measure based on previous period prices. Nevertheless, we find essentially no correlation between either measure of signal volumes and collusive efficiency. A second experiment demonstrates that underlying seller propensities to cooperate more clearly affect collusiveness.