Abstract Latent personality traits underpinning observed behavioral variation have been studied in a great many species. However, a lack of standardized behavioral assays, coupled to a common reliance on inferring personality from a single, observed, behavioral trait makes it difficult to determine if, when, and how conclusions can be directly compared across taxa. Here, we estimate the among-individual (co)variance structure (ID) for a set of four behaviors expressed in an open field trial, putatively indicative of boldness, in seven species of small freshwater fish. We show that the ID matrices differ in terms of the total amount of variation present, and crucially the orientation, and as a consequence, biological interpretation of the first eigenvector. Specifically, loading of observed traits on the main axis of variation in ID matched a priori expectations for a shy-bold continuum in only three of the seven cases. Nonetheless, when the “shape” of the matrices was compared in higher dimensions, there was a high level of similarity among species, and weak evidence of phylogenetic signal. Our study highlights the present difficulty of trying to compare empirical inferences about specific personality traits across studies. However, it also shows how multivariate data collection and analysis allows the structure of behavioral variation to be quantitatively compared across populations or species without reliance on ambiguous verbal labels. This suggests that the field may have much to gain from greater uptake of phylogenetically informed comparative approaches when seeking to test evolutionary hypotheses about the origin and maintenance of personality variation.

中文翻译：

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动物人格变异结构的比较方法

摘要：已经在许多物种中研究了支撑观察到的行为变异的潜在人格特征。然而，缺乏标准化的行为分析，加上普遍依赖于从单一的、观察到的行为特征来推断个性，使得很难确定是否、何时以及如何在分类单元之间直接比较结论。在这里，我们估计了七种小型淡水鱼在露天试验中表达的一组四种行为的个体间（共）方差结构（ID），这四种行为被认为表明了大胆性。我们表明，ID 矩阵在存在的变异总量方面有所不同，最重要的是在方向方面有所不同，因此，第一个特征向量的生物学解释也是不同的。具体来说，在七个案例中，只有三个案例中，ID 变异主轴上观察到的特征负载符合害羞大胆连续体的先验预期。尽管如此，当在更高维度上比较矩阵的“形状”时，物种之间存在高度相似性，并且系统发育信号的证据微弱。我们的研究强调了目前尝试比较不同研究中关于特定人格特质的经验推论的困难。然而，它还展示了多变量数据收集和分析如何允许在不依赖模糊的语言标签的情况下定量比较不同种群或物种的行为变异结构。这表明，在寻求检验有关人格变异的起源和维持的进化假设时，该领域可能会从更多地采用系统发育学的比较方法中获益匪浅。