Animal personality is defined as consistent individual differences across time and situations, but little is known about how or when those differences are established during development. Likewise, several studies described the personality structure of adult capuchin monkeys, without assessing the ontogeny of these personality traits. We analyzed the behavioral repertoire of 12 wild infants (9 males, 3 females) yellow‐breasted capuchin monkeys (Sapajus xanthosternos), in Una Biological Reserve (Bahia, Brazil). Each infant was observed and filmed weekly from birth until 36 months, through daily focal sampling. We analyzed the behavior of each individual in 10 developmental points. By means of component reduction (principal component analysis), we obtained four behavioral traits: Sociability, Anxiety, Openness, and Activity. We investigated whether there were developmental effects on those traits by fitting regression models for the effect of time on behavioral traits, controlling for monkey identity, sex, and cohort. Sociability (decreasing) and Anxiety (increasing) changed significantly along development. By means of repeatability analysis, we did not find intra‐individual consistency across time in those traits, so we cannot discriminate stable personality traits in early ontogeny. Our results show that the personality structure of capuchin monkeys is not established during early development, in agreement with the literature on human personality.

中文翻译：

---

对野生卷尾猴行为发展的纵向评估：前三年未建立人格

动物性格被定义为在不同时间和情况下的一致个体差异，但是对于在发育过程中如何或何时建立这些差异知之甚少。同样，一些研究描述了成年卷尾猴的人格结构，而没有评估这些人格特征的个体发育。我们分析了12头黄胸卷尾猴（Sapajus xanthosternos）的野生婴儿（9例雄性，3例雌性）的行为表），位于Una Biological Reserve（巴西巴伊亚州）。从出生到36个月，每周进行观察，并通过每日焦点采样每周对每个婴儿进行拍摄。我们分析了10个发展点中每个人的行为。通过减少成分（主要成分分析），我们获得了四个行为特征：社交性，焦虑性，开放性和活动性。我们通过对时间对行为特征的影响进行回归模型拟合，控制猴子的身份，性别和队列来研究这些特征是否对发育有影响。随着发展，社交能力（减少）和焦虑症（增加）发生了显着变化。通过可重复性分析，我们没有发现这些特征在时间上的个体内一致性，因此我们不能区分个体发育早期的稳定人格特征。