Politics and International Relations, University of Edinburgh, Edinburgh EH8 9LD, UK.
Nature. 2011 Sep 14;477(7364):317-20. doi: 10.1038/nature10384.
Confidence is an essential ingredient of success in a wide range of domains ranging from job performance and mental health to sports, business and combat. Some authors have suggested that not just confidence but overconfidence--believing you are better than you are in reality--is advantageous because it serves to increase ambition, morale, resolve, persistence or the credibility of bluffing, generating a self-fulfilling prophecy in which exaggerated confidence actually increases the probability of success. However, overconfidence also leads to faulty assessments, unrealistic expectations and hazardous decisions, so it remains a puzzle how such a false belief could evolve or remain stable in a population of competing strategies that include accurate, unbiased beliefs. Here we present an evolutionary model showing that, counterintuitively, overconfidence maximizes individual fitness and populations tend to become overconfident, as long as benefits from contested resources are sufficiently large compared with the cost of competition. In contrast, unbiased strategies are only stable under limited conditions. The fact that overconfident populations are evolutionarily stable in a wide range of environments may help to explain why overconfidence remains prevalent today, even if it contributes to hubris, market bubbles, financial collapses, policy failures, disasters and costly wars.
自信是从工作表现和心理健康到体育、商业和战斗等广泛领域成功的关键因素。一些作者认为，不仅是自信，而且是过度自信——相信自己比实际情况更好——是有利的，因为它有助于提高雄心、士气、决心、毅力或虚张声势的可信度，从而产生自我实现的预言，即夸大的自信实际上增加了成功的可能性。然而，过度自信也会导致错误的评估、不切实际的期望和危险的决策，因此，这种错误的信念如何在包括准确、无偏见的信念在内的竞争策略的人群中演变或保持稳定仍然是一个谜。在这里，我们提出了一个进化模型，表明与直觉相反，过度自信会使个人适应度最大化，并且只要竞争成本与争夺资源的收益相比足够大，群体就会变得过度自信。相比之下，只有在有限的条件下，无偏策略才是稳定的。过度自信的群体在广泛的环境中具有进化稳定性这一事实，可能有助于解释为什么过度自信在今天仍然普遍存在，即使它导致了傲慢、市场泡沫、金融危机、政策失败、灾难和代价高昂的战争。
