The study of individual behavioral variation, sometimes called animal personalities or behavioral types, is now a well-established area of research in behavioral ecology and evolution. Considerable theoretical work has developed predictions about its ecological and evolutionary causes and consequences, and studies testing these theories continue to grow. Here, we synthesize the current empirical work to shed light on which theories are well supported and which need further refinement. We find that the major frameworks explaining the existence of individual behavioral variation, the pace-of-life syndrome hypothesis and state-dependent feedbacks models, have mixed support. The consequences of individual behavioral variation are well studied at the individual level but less is known about consequences at higher levels such as among species and communities. The focus of this review is to reevaluate and reestablish the foundation of individual behavioral variation research: What do we know? What questions remain? And where are we going next?

中文翻译：

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一致的个人行为变异：我们知道什么以及我们要去哪里？

对个体行为变异的研究，有时称为动物性格或行为类型，现已成为行为生态学和进化论的一个成熟的研究领域。大量的理论工作已经对其生态和进化的原因和后果进行了预测，并且测试这些理论的研究也在不断增长。在这里，我们综合了当前的实证工作，以阐明哪些理论得到了很好的支持，哪些理论需要进一步完善。我们发现解释个体行为变异存在的主要框架、生活节奏综合症假说和状态依赖反馈模型得到了不同的支持。个体行为变异的后果在个体层面上得到了很好的研究，但对更高层面（例如物种和群落之间）的后果知之甚少。本综述的重点是重新评估和重建个体行为变异研究的基础：我们知道什么？还剩下什么问题？接下来我们要去哪里？