This special issue looks at how cognitive bias matters to international law. We wish to shed light on the legal frames, labels, and cognitive biases that shape our understanding of international rules, the application of these rules and outcomes of international adjudicatory processes. Adopting the behavioural approach to international law, we focus on actual rather than assumed behaviour of actors taking part in the international legal process. The central idea of this approach is that human cognitive capacities are limited (or bounded) by a variety of cognitive, emotional and social or group-based biases. Our aim is to explore how these biases operate on the individual, group, and state level in various spheres of international law. This Symposium therefore looks beyond the traditional understanding of international law as applying between states and focuses on how individuals as actors in the international sphere use international law language to influence other people, to create communities and to shape identities.

This Introduction first serves to explain the type of shortcuts we make in our decision-making. This description of biases is followed by an overview of behavioural literature in international law that has thus far examined how bias operates in different aspects of international law – in relation to sources, to compliance, and individuals taking part in the international legal process. We then turn to introduce the Symposium and explain its contribution to the existing literature.