Behavioral International Law: An Introduction

[Tomer Broude is Vice-Dean and Sylvan M. Cohen Chair in Law at the Faculty of Law and Department of International Relations at the Hebrew University of Jerusalem.]

I’d like first to thank the Opinio Juris team, and particularly Prof. Chris Borgen, for inviting me to present my article manuscript, “Behavioral International Law”, in this online forum. Today I will devote my post to general observations on this project. In my second post I will discuss the range of available research methodologies in this area. A third post will discuss some concrete examples of behavioral research in international law.

Behavioral science has in recent years been applied successfully to many legal issues. A field that just a decade ago was entirely new now merits its own research handbooks (one forthcoming with OUP in 2014, edited by my Hebrew University colleagues Doron Teichman and Eyal Zamir). Behavioral research is now embedded in national and regulatory policy-making that clearly interacts with international affairs (see Cass Sunstein’s article on “Nudges.gov” here; the UK’s Behavioural Insights Team; and this conference in December on EU law and behavioral science). No less importantly, the groundbreaking work of cognitive psychologists such as Daniel Kahneman and the late Amos Tversky has been greatly popularized in a series of popular science books (see here, here, and here), making it more accessible to lawyers and policy-makers (for better or for worse).

Simplified, the central concept underlying research in this field is the recognition that human cognitive capabilities are not perfect or infinite; our rationality is ‘bounded’. The human brain makes shortcuts in judgment and decision-making that diverge from expected utility theory. Limiting aspects of bounded rationality and the shortcuts taken to overcome them – generally known as biases and heuristics – inevitably cause human decisions that would be regarded as erroneous if compared with theoretically/perfectly rational outcomes. As I explain in the article, this should at least give pause to standard rational choice approaches to law in general and international law in particular, whose assumptions about the rationality of states and other actors are often distant from behavioral realities.

Having said this, it is important to understand that behavioral economics does not aspire to replace one ideal-type decision maker (a perfectly rational one) with another (rationally imperfect) one. Rather, the behavioral research agenda aims to explore the characteristics of real decision-making processes of different types of actors, under different circumstances. So far, various important generalizable characteristics have been identified, but behavioralists do not claim that they exist equally among all decision-makers in all cases and under all conditions. The importance of a behavioral approach to international legal research, therefore lies mainly – but not exclusively – in its enhancement of the “empirical turn” in international law. Louis Henkin once asked “How Nations Behave”. Hypotheses and methods from behavioral science can help in answering this question, and others affecting the operation of international law.

Behavioral research has already entered the domain of international law, employed by both legal scholars and political scientists. These include applications of prospect theory to international trade disputes by Deborah Kay Elms; discussions of psychological effects on reactions to mass atrocities, as a cooperation between psychologists and legal scholars Ryan Goodman and Derek Jinks; applications of the behavioral availability bias to bilateral investment treaties, by Lauge Skovgaard and Emma Aisbett; a study of treaty design by Jean Galbraith; and ongoing experimental work by Emilie Hafner-Burton, David Victor and others at the University of California – San Diego, that focuses on behavioral traits of elite decision-makers.

These are significant contributions by any measure, and in themselves demonstrate the diversity of research that can emerge in this field. But it can also be opaque to international lawyers. In my article, I try to simplify (but not exaggerate) and systematize the variety of methods in which behavioral research can illuminate puzzles and problems in international law. I provide a general framework for engaging in such research and for engaging with it.

In this introduction, I would like to emphasize three inter-related points, before moving on to the methodologies and examples.

First, behavioral research is not merely an extension of law and economics or rational choice. Cognitive psychology can provide us with insights about human decision-making, without necessarily resorting to rational choice. For example, in the manuscript I discuss group dynamics (dissent vs. conformity) in judicial decision-making in the WTO. This discussion is informed by behavioral science, but in fact has more in common with sociological approaches to law than with rational choice. In keeping with the general call for caution in the advent of this type of research, I have deliberately eschewed terms (and their acronyms) such as “Behavioral Law and Economics”, let alone “Behavioral International Law and Economics”. I would not wish to see such a rich and inspirational field pigeonholed into the frames of rational choice and law and economics, that have proven disappointing in several senses. I am convinced that behavioral insights hold the power to illuminate a broad range of international legal issues outside of these now traditional, sometimes jaded, frameworks.

Second, behavioral research of international law is not another “-ism”. It does not hold a particular descriptive world view relating to the role of power in international relations, for example. Some “-isms” might prefer to ignore cognitive dimensions; that does not strengthen their claims.

Third, perhaps most importantly, though closely related to the former observation, behavioral international law is not, and should not be considered, to be a normative theory of law. Examining the way states, collectives and individuals engage within legal frameworks is first and foremost an empirical exercise. What we do with that knowledge becomes normative. Thus, as I will explain in more detail in a subsequent post, understanding the ways in which military commanders and targeting officers may succumb (or not) to decision-making biases relating to proportionality under international humanitarian law, is important because it can help us evaluate the effectiveness of international law – its substantive rules, its frames, its procedures – within its own normative constructions. This may lead to policy and legal recommendations, but would not necessarily alter the overarching normativity.