Information about dangers can spread effectively by observation of others’ threat responses. Yet, it is unclear if such observational threat information interacts with associative memories that are shaped by the individual’s direct, firsthand experiences. Here, we show in humans and rats that the mere observation of a conspecific’s threat reactions reinstates previously learned and extinguished threat responses in the observer. In two experiments, human participants displayed elevated physiological responses to threat-conditioned cues after observational reinstatement in a context-specific manner. The elevation of physiological responses (arousal) was further specific to the context that was observed as dangerous. An analogous experiment in rats provided converging results by demonstrating reinstatement of defensive behavior after observing another rat’s threat reactions. Taken together, our findings provide cross-species evidence that observation of others’ threat reactions can recover associations previously shaped by direct, firsthand aversive experiences. Our study offers a perspective on how retrieval of threat memories draws from associative mechanisms that might underlie both observations of others’ and firsthand experiences.

通过观察他人的威胁反应，有关危险的信息可以有效传播。然而，尚不清楚这种观察到的威胁信息是否与由个人直接、第一手经验形成的联想记忆相互作用。在这里，我们在人类和老鼠身上证明，仅仅观察同种人的威胁反应就会恢复观察者先前学习和消除的威胁反应。在两项实验中，人类参与者在以特定情境的方式恢复观察后，对威胁条件线索表现出更高的生理反应。生理反应（唤醒）的升高进一步特定于被观察为危险的环境。在老鼠身上进行的一项类似实验通过观察另一只老鼠的威胁反应后证明防御行为的恢复提供了趋同的结果。总而言之，我们的研究结果提供了跨物种的证据，表明观察他人的威胁反应可以恢复以前由直接、第一手的厌恶经历形成的关联。我们的研究提供了一个视角，即威胁记忆的检索如何从可能是对他人观察和第一手经验的基础的联想机制中提取。