Neuroscience and Behavior Unit, California National Primate Research Center, University of California, Davis, California, USA.
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California, USA.
Am J Primatol. 2024 Apr;86(4):e23591. doi: 10.1002/ajp.23591. Epub 2024 Jan 11.
Individual differences of infant temperament have been associated with future health outcomes that provide explanatory power beyond adult personality. Despite the importance of such a metric, our developmental understanding of personality-like traits is poor. Therefore, we examined whether young primates show consistency in personality traits throughout development. We replicated a Biobehavioral Assessment (BBA) at three time periods: 3-4 months, 1 year, and 2 years of age in 47 rhesus macaque (Macaca mulatta) subjects from large mixed-sex outdoor social housing units at the California National Primate Research Center. We report results for tests focused on responses and adaptation to the temporary separation and relocation, responses to a threatening stimulus, and ratings of overall temperament. We found consistently repeatable associations in measures of Emotionality; these associations were stronger in males, but also present in females, and broadly consistent between Years 1 and 2. We also explored whether behavioral responses to this experimental relocation might be influenced by their experience being relocated for other reasons (i.e., hospitalizations) as individuals' responses might be influenced by similar experiences to the BBA procedure. Only locomotion, during one of the assessments, was associated with past hospitalization events. Overall, repeatability in Emotionality-associated behaviors was evident across the 2 years, in both sexes. We did, however, find evidence of the emergence of sex differences via differentiated expression of behavioral responses during the BBA. We emphasize that there is likely contextual nuance in the use of these BBA factor-associated behaviors. Further research is required to determine whether and how shifts occur in underlying factor structure and the expression of associated behaviors.
婴儿气质的个体差异与未来的健康结果有关，这些结果提供了超越成人个性的解释力。尽管这种衡量标准很重要，但我们对类似个性的特征的发展理解还很薄弱。因此，我们研究了年轻灵长类动物在整个发育过程中是否表现出个性特征的一致性。我们在三个时间段重复了一项生物行为评估（BBA）：3-4 个月、1 岁和 2 岁，共有 47 只恒河猴（Macaca mulatta）来自加利福尼亚国家灵长类动物研究中心的大型混合性别户外社会住房单元。我们报告了针对对临时分离和重新安置的反应和适应、对威胁刺激的反应以及整体气质评分的测试结果。我们发现情感测量中存在一致的可重复关联；这些关联在雄性中更强，但在雌性中也存在，并且在 1 年和 2 年之间大致一致。我们还探讨了个体对这种实验性重新安置的行为反应是否可能受到他们因其他原因（即住院）而被重新安置的经历的影响，因为个体的反应可能会受到与 BBA 程序类似的经历的影响。只有在其中一次评估中的运动，与过去的住院事件有关。总体而言，情感相关行为在两性中在 2 年内都具有可重复性。然而，我们确实发现了性行为差异出现的证据，这是通过 BBA 期间行为反应的差异化表达表现出来的。我们强调，在使用这些 BBA 因子相关行为时，可能存在上下文细微差别。需要进一步的研究来确定是否以及如何在潜在的因子结构和相关行为的表达中发生转变。
