Building from the Brain: Advancing the Study of Threat Perception in International Relations

“Threat perception” is frequently invoked as a causal variable in theories of international relations and foreign policy decision making. Yet haphazard conceptualization and untested psychological assumptions leave its effects poorly understood. In this article, I propose a unified solution to these two related problems: taking the brain into account. I first show that this approach solves the conceptualization problem by generating two distinct concepts that generalize across existing theories, align with plain language, and are associated with specific brain-level processes: threat-as-danger perception (subjectively apprehending danger from any source) and threat-as-signal perception (detecting a statement of the intention to harm). Because both types of perception occur in the brain, large-scale neuroimaging data capturing these processes offer a way to empirically test some of the psychological assumptions embedded in IR theories. I conduct two such tests using assumptions from the literatures on conflict decision making (“harms are costs”) and on coercion (“intentions are inscrutable”). Based on an original analysis of fifteen coordinate-based meta-analyses comprising 500+ studies and 11,000+ subjects, I conclude that these assumptions are inconsistent with the cumulative evidence about how the brain responds to threats of either kind. Further, I show that brain-level data illuminate aspects of threat perception's impact on behavior that have not yet been integrated into IR theory. Advancing the study of threat perception thus requires a microfoundational approach that builds from what we know about the brain.