An evolutionary model of price competition among spatially distributed firms

Various studies have shown the emergence of cooperative behavior in evolutionary models with spatially distributed agents. We investigate to what extent these findings generalize to evolutionary models of price competition among spatially distributed firms. We consider both one- and two-dimensional models, and we vary the amount of information firms have about competitors in their neighborhood. Our computer simulations show that the emergence of cooperative behavior depends strongly on the amount of information available to firms. Firms tend to behave most cooperatively if they have only a very limited amount of information about their competitors. We provide an intuitive explanation for this phenomenon. Our simulations further indicate that three other factors in our models, namely the accuracy of firms’ information, the probability of experimentation, and the spatial distribution of consumers, have little effect on the emergence of cooperative behavior

Imitation with Intention and Memory: an Experiment

Three results emerge from a simple experiment on imitation. First, I find behavior which strongly suggests an intention to imitate. Second, players im- itate successful other players rather than repeating successful actions. Third, to find imitation examples, players use several periods of memory. This lends support to learning models with a non-trivial role of memory. The experiment analyzes imitation in an individual learning context. It sup- plements the results obtained for imitation in evolutionary processes.Imitation, Learning, Memory, Experiments

Imitation and the evolution of walrasian behavior : theoretically fragile but behaviorally robust

A well-known result by Vega-Redondo implies that in symmetric Cournot oligopoly, imitation leads to the Walrasian outcome where price equals marginal cost. In this paper we show that this result is not robust to the slightest asymmetry in fixed costs. Instead of obtaining the Walrasian outcome as unique prediction, every outcome where agents choose identical actions will be played some fraction of the time in the long run. We then conduct experiments to check this fragility. We obtain that, contrary to the theoretical prediction, the Walrasian outcome is still a good predictor of behavior

Imitation - Theory and Experimental Evidence

We introduce a generalized theoretical approach to study imitation models and subject the models to rigorous experimental testing. In our theoretical analysis we find that the different predictions of previous imitation models are due to different informational assumptions, not to different behavioral rules. It is more important whom one imitates rather than how. In a laboratory experiment we test the different theories by systematically varying information conditions. We find that the generalized imitation model predicts the differences between treatments well. The data also provide support for imitation on the individual level, both in terms of choice and in terms of perception. But imitation is not unconditional. Rather individuals' propensity to imitate more successful actions is increasing in payoff differences.Evolutionary game theory; Stochastic stability; Imitation; Cournot markets; Experiments

Learning and cooperation in network experiments

In this paper we study learning and cooperation in repeated prisoners' dilemmas experiments. We compare interaction neighbourhoods of different sizes and structure and we observe choices under different information conditions and estimate parameters of a learning model. We test robustness of the eastimator. We find that imitation, albeit a driving force in many models of spatial evolution, is often a negligible factor in the experiment. As a result, we find less cooperation