Diplomacy has an odd relationship with International Relations (ir) theory, particularly in the American context. While few scholars would likely argue that diplomacy is not a ubiquitous part of quotidian life in international politics or that summitry has been the site of significant breakthroughs and breakdowns, historically the practice of diplomacy has not been treated as one that carries significant causal impact on outcomes. There are several reasons for this, including the domination of structural theories that privilege the distribution of capabilities, institutions, and ideas. ¹ The main wager behind structural theories is that any individual agent, such as a diplomat, ambassador, or even leader, is going to be severely constrained and will have limited impact on outcomes. Diplomats are, as I have argued elsewhere, “more or less along for the ride” in these theories. ² Other reasons include significant skepticism about the utility of the interpersonal diplomatic meeting: in a world where anyone can dissemble or lie, of what use is diplomacy? At the end of the day the “problem of other minds” prevents any leader or diplomat from gaining sufficient access to the minds of their interlocutors and thus deriving the intentions of others is believed to be possible only through theorization and approximation. Costly signals, rather than cheap talk, convey information. From this vantage point it is easy to see how diplomacy may not only be viewed irrelevant, it could also be dangerous, as infamous examples such as Yalta and Munich illustrate. Misperception, in other words, looms large and the stakes are simply too big to rely on imprecise measures of intentions. A final problem relates to methods. It has, traditionally, been difficult for political scientists to study individuals, and their interactions in diplomacy, systematically: they are complex, messy, quirky, idiosyncratic and, it would appear, resist systemized attempts at explanation or prediction. Put simply, leaders and diplomats just might be sui generis as individuals, resisting scientific study. Therefore, in addition to questions of whether diplomacy matters for international politics, a key question remained as to how to study it, if it does.

This skeptical and dismissive American perspective not only puts itself in direct contrast to other approaches to international politics, such as the English School, which both takes diplomacy seriously and often views the international as the diplomatic, but also with practitioners of international politics who have long highlighted the virtues of meeting with friends and adversaries, during periods of both stasis and crisis, in order to maintain and build relationships. ³ As u.s. Vice President Joe Biden recently put it, “the conduct of foreign policy [is] personal […] You have to figure out what is realistically possible […] That requires establishing real relationships.” ⁴ Thus, the odd relationship of diplomacy to American ir is that there is a severe disjuncture between American ir theorizing on the one hand and what actual policymakers and diplomats report as important on the other. Why does this disjuncture persist, is the view changing, and will the two perspectives ever be fully reconciled? In what follows I will make the case that new social science methods, beginning to pay dividends in ir, offer significant promise in bridging this gap.

After the end of the Cold War, an event that structural theories did not anticipate and had difficulty explaining, a renewed interest in “first image” or individual-level theorizing emerged. Individual-level theories were used as a way of explaining transformational moments, conducted by individual diplomats and leaders, that changed the structure of the system. Eschewing grand claims about human nature, this renaissance takes a more nuanced and circumspect approach to diplomacy and above all highlights the relational or interactional elements of sociality that can create structures. It is diverse in orientation and interdisciplinary in approach, bringing in insights from psychology, sociology, social theory, biology, and other fields. ⁵ At the same time, insights from neuroscience have begun to provide insights into social interaction at a micro-foundational level, problematizing many of the assumptions made by skeptics. The ability to judge sincerity through face-to-face interactions, for example, not only has a long-standing basis in psychological studies, but is also buttressed by recent insights into how our brains operate in the context of a face-to-face interaction.

My own work attempts to reconcile the practitioner experience of diplomacy as an invaluable tool with ir’s general skeptical approach to the activity. As I argue in Face-to-Face Diplomacy: Social Neuroscience and International Relations, findings from psychology and neuroscience suggest that in face-to-face interactions individuals are better able to understand the intentions of one another. ⁶ Crucially, intention understanding is a precursor to trust building, an activity that ultimately allows leaders to transform relationships of enmity. Nicholas Wheeler, for example, argues that interpersonal bonding, through processes of face-to-face diplomacy, allow leaders to develop interpersonal bonded trust and escape the most deleterious aspect of the security dilemma: suspicion that the other side will defect. ⁷ Put another way, the disjuncture between American theories of ir and the practice of diplomacy can be bridged by bringing in interdisciplinary insights and methods that allow us to problematize the theoretical reasons why diplomacy was undervalued in the first place. In the end, we have an age-old practice (diplomacy) attempting to solve an age-old problem (security dilemma) brought into the 21st century through interdisciplinary methods (psychology and neuroscience).

Precisely because such an approach is interdisciplinary, dialogue across and among disciplines that engage in social interaction is necessary. Recent work on the utility of face-to-face diplomacy in intention understanding and trust building have identified several questions that will drive future research and can only be answered through dialogue with a variety of disciplines and borrowing their methods. I will outline four with the remaining space available.

First, drawing from psychology, diplomacy theorists have argued that psychological attributes such as traits, personality, and dispositions each have important effects on negotiation styles, decisions to engage diplomatically, or the ability to persuade others. One of the crucial questions that remains under-theorized concerns the interaction effects that occur when personality traits are pitted against one another. On the less extreme end, how do individuals with high/low emotional intelligence interact? More extreme, can two leaders with dark triad personality characteristics, for example, successfully negotiate and build trust with one another? Understanding not only how individual traits shape decision-making, but also how those traits interact with others who may have similar or divergent traits, will provide more nuanced understanding of what occurs in an interaction when leaders or diplomats meet.

Second, studies in neuroscience have demonstrated a remarkable ability for the human brain to rewire itself as a result of social interaction as well as merely thinking about sociality. Very short term training of different emotional capacities, such as empathy or compassion, lead not only to different decisions in economic games, but plastic changes at the neural level itself. It is likely that in the near future social neuroscience will allow us to hone in on what exactly activates prosocial cooperative behaviors in individuals, what activates selfishness and strategic thinking that leads to defection, and durability in how long the plastic changes in the brain remain after training. These insights may well lead to a revolution in how diplomats are trained in the classroom before engaging in diplomatic social interactions.

Third, one of the challenges posed to students of diplomacy and summitry is that it is very difficult to predict a priori when a diplomatic encounter will result in the creation of a positive social bond and when it will result in frustration or even anger. The normatively positive outcome of better understanding and ultimately trust that engendered between Mikhail Gorbachev and Ronald Reagan starting in Geneva 1985 is met by the disappointment felt by Vladimir Putin and Barack Obama over the course of several meetings between 2009–2015. How can we predict when leaders or diplomats will “hit it off” and when the relationship is doomed to fall flat? Micro-sociology may provide one set of answers. Randall Collins draws on a rich intellectual tradition of focusing on interaction rituals, building on Emile Durkheim and Erving Goffman, in this case face-to-face interactions in dyads or small groups, in order to theorize the experience of creating positive emotional energy, or personal chemistry. ⁸ The wager of the micro-sociological perspective is that while each interaction is unique in some regards – the individuals involved, issues discussed, positions/interests of the parties – we can nevertheless delineate particular structural characteristics of successful interaction rituals and use them to make predictions about what will come of a diplomatic interaction.

Finally, diplomacy has traditionally been studied from a decidedly classical physics perspective. States as “billiard balls,” diplomats and leaders as autonomous “rational agents,” one-way “causal forces,” and negotiation between “unitary actors” are the metaphors, and indeed the causal thinking, of most approaches to international security generally and diplomacy more specifically. Quantum theory, derived from insights in quantum mechanics, problematizes many of these metaphors at the subatomic level and raises questions about the nature of diplomacy and how we should be studying it if the quantum model applies at the macroscopic level, as some suggest may indeed be the case. ⁹ For example, entanglement, the notion that seemingly separate actors and events as viewed through a classical lens are actually interconnected to such an extent that each cannot be described independently from the other, implies a level of connection between human beings, groups, and institutions that we have yet to fully understand or appreciate. As Der Derian puts it, it may be that diplomacy is shifting away from “negotiation between states to negotiation among cities, municipalities, streets, and other byways of authority and representation.” ¹⁰ There are ramifications for the face-to-face dyadic meeting between individuals as well. As Wendt argues, while the classical model of interaction assumes that “minds are separable information-processing machines in well-defined states,” a quantum evaluation would suggest that “our minds are entangled through language and context and thus not fully separable.” ¹¹ The upshot for the problem of other minds, buttressing the neuroscience findings discussed above, is that through entanglement individuals are able to experience meaning directly, through language and context, rather than making inferences about their meaning. Note that this does not mean that individuals always express themselves in the way they intend, but rather “given how effortless everyday communication is, such cases are likely to be the exception rather than the norm.” Our dialogue with quantum has just begun and may well cause theorists to re-evaluate and re-theorize the meaning of diplomacy, from the ground up.

Each of these questions, and sources of dialogue between disciplines, has implications not only for how diplomacy is analyzed and how the role of diplomats is understood, but practiced as well. In particular, insights from psychology, neuroscience, sociology, and quantum may well lead to adjustments in how diplomats, and policymakers, are trained as well as how they undertake assignments. Traditional diplomatic training has tended to focus on core practice-oriented aspects of the job: negotiation and mediation, diplomatic protocol, and multilateral cooperation. The four areas of dialogue identified above point to the possibility of a different kind of training, one focused more concretely on the human element of diplomatic interaction and privileging the benefits of short-term training exposure on prosocial behaviors (understood not as naïve caring and sympathy, but rather attuned empathy and understanding of the other). As Olga Klimecki and colleagues have persuasively argued, plasticity of the brain means that we can train ourselves to react in certain ways to particular stimuli. ¹² Our emotional responses, and the brain functions that give rise to those reactions, are changeable and moldable through training. When trained in compassion, positive emotional responses and prosocial behaviors often follow. Training in intention understanding processes and social bond formation may similarly result in productive changes in practice.

In the end, while ir theory in the American context has been slow to appreciate diplomacy’s value and the nature of the ubiquitous diplomatic encounter, trends in social science methodologies, including psychology and neuroscientific, combined with recent insights from interdisciplinary perspectives, such as micro-sociological or even quantum mechanics, suggest a strong value of International Relations scholarship for the study of diplomatic history and diplomacy more generally. These insights not only help to shed light on the wisdom of practitioner claims regarding the utility of such practices, but may also serve as productive ways of changing diplomacy in the future.