Imitation and the Evolution of Walrasian Behavior: Theoretically Fragile but Behaviorally [Dataset]

A well-known result by Vega-Redondo (1997) [18] implies that in symmetric Cournot oligopolies, imitation leads to the Walrasian outcome. We show that this result is not robust to the slightest asymmetry in costs, since 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 predictio
n, the Walrasian outcome is a good predictor of market outcomes. Finally, we suggest a new theory based on a mix of imitation and other learning processes that explains subjects' behavior fairly well.

Vega-Redondo（1997）[18]提出的经典结论指出，在对称古诺寡头垄断（Cournot oligopolies）市场中，模仿行为会导向瓦尔拉斯（Walrasian）结果。我们的研究表明，该结论在存在极细微成本不对称的场景下并不稳健：从长期视角来看，任意行为人选择完全相同行动的结果，都会以一定比例出现。随后我们开展实验以验证这一理论脆弱性，结果却与理论预测相悖——瓦尔拉斯结果能够较好地预测市场运行结果。最后，我们提出了一种融合模仿与其他学习过程的全新理论，该理论可以较为合理地解释实验被试的行为表现。