Existing scholarship on animal models tends to foreground either of the two major roles research organisms play in different epistemic contexts, treating their representational and instrumental roles separately. Based on an empirical case study, this article explores the changing relationship between the two epistemic roles of a research organism over the span of a decade, while the organism was used to achieve various knowledge ends. This rat model was originally intended as a replica of human susceptibility to cardiac arrest. In a fortunate stroke of serendipity, however, the experimenters detected the way mother-infant interactions regulated the pups’ resting cardiac rate. This intriguing outcome thus became the model’s new representational target and began driving the development of an experimental system. Henceforth, the model acquired an instrumental function, serving to detect and measure system-specific differences. Its subsequent development involved creating stimulus-response measures to explain and theorize those differences. It was this instrumental use of the model that pushed the experimenters into unchartered territory and conferred to the model an ability to adapt to varied epistemic contexts. Despite the prominence of this instrumental role, however, the model’s representational power continued to guide research. The model’s representational target was widened beyond heart rate to reflect other functional phenomena, such as behavioral activity and sleep/wake rhythm. The rat model was thus transformed from an experimental organism designed to instantiate cardiac regulation to a model organism taken to represent the development of a whole, intact animal under the regulatory influence of maternal care. This article examines this multifaceted transformation within the context of the salient shifts in modeling practice and variations in the model’s representational power. It thus explores how the relationship between the representational and instrumental uses of the model changed with respect to the varying exigencies of the investigative context, foregrounding its contextual versatility.

现有的动物模型研究倾向于突出研究生物在不同认知背景下所扮演的两个主要角色中的任何一个，分别处理它们的代表性和工具性角色。本文基于一个实证案例研究，探讨了一个研究有机体在十年间的两个认知角色之间的变化关系，而该有机体被用来实现各种知识目的。该大鼠模型最初旨在作为人类心脏骤停易感性的复制品。然而，幸运的是，实验人员发现了母婴互动调节幼崽静息心率的方式。因此，这个有趣的结果成为模型的新代表性目标，并开始推动实验系统的开发。今后，该模型获得了一个工具功能，用于检测和测量系统特定的差异。它的后续发展涉及创建刺激反应措施来解释和理论化这些差异。正是这种对模型的工具性使用将实验者推向了未知领域，并赋予模型适应各种认知背景的能力。然而，尽管这种工具性作用很突出，但该模型的代表性力量继续指导着研究。该模型的代表性目标已扩大到心率以外，以反映其他功能现象，例如行为活动和睡眠/清醒节律。因此，大鼠模型从旨在实例化心脏调节的实验有机体转变为代表整体发育的模型有机体，在母体护理的监管影响下的完整动物。本文在建模实践的显着变化和模型表示能力的变化的背景下研究了这种多方面的转变。因此，它探讨了模型的代表性和工具性使用之间的关系如何随着调查背景的不同紧急情况而变化，突出了其背景的多功能性。