(Editor’s note: This article is part of a Just Security series on the newly released “Principles on Effective Interviewing for Investigations and Information Gathering,” an expert-led initiative responding to a 2016 appeal to the U.N. General Assembly by then-U.N. Special Rapporteur Juan E. Méndez to develop such standards. The series outlines the origins and the scientific, legal, and ethical underpinnings of the guidelines, also known as the “Méndez Principles” in honor of its co-chair.)

During World War II, U.S. Navy Lieutenant Otis Cary was tasked with interrogating highly resistant Japanese prisoners-of-war (POWs). Unlike most of his fellow interrogators, Cary was both fluent in Japanese and intimately familiar with the complexities of Japanese culture. As a result, he was able to communicate in a clear and appropriately respectful manner. This allowed him to establish common ground between himself and the POWs by describing various experiences he had had while living in pre-war Japan. By expressing his abiding appreciation for the honorable sacrifices the POWs had made for their country – and how he thought Japan would recover from the war (an unpopular opinion to most Americans at the time) – Cary was able to establish rapport and trust with these POWs. A U.S. government study determined that he treated the POW’s in a “decent, humane manner … not as enemies, but as human beings.” Although Cary was an interrogator, not an ambassador, this approach nonetheless created an operationally useful relationship with the POWs that elicited vital intelligence.

This brief example is but one anecdotal illustration of what decades of behavioral science research has now reliably demonstrated: a rapport-based approach to interviewing subjects (criminal suspects, victims, witnesses, as well as intelligence sources) can help to secure a cooperative mindset and produce reliable disclosures. Indeed, work over the past decade has shown the value of these approaches in experimental laboratory research and in real-world settings, with field validation studies confirming the benefit of training interrogators in such approaches. Many of the studies have emerged from the extensive and wide-ranging research sponsored by the U.S. inter-agency High-Value Detainee Interrogation Group, or HIG.

Using such evidence-based tactics to build rapport and trust can set the stage for an ethical and effective interview.

Building Rapport 

Rapport is an interactive concept that characterizes the relationship between an interviewer and a subject (which can vary over time). An interrogation is typically perceived as beginning when rapport is absent, with the interrogator attempting to develop it at the outset and working to maintain it throughout (and sometimes reclaim it when lost). A popular theoretical conception of establishing rapport suggests that three elements must be present. First, both parties should be focused on the same objectives and attuned to a common mindset. Second, the interaction should flow comfortably. And third, both parties should generally have positive feelings toward one another.

Conversational rapport can be developed through questioning tactics that demonstrate respect and empathy. The interviewer is encouraged to give up some measure of control and therein allow the subject to provide their perspective without interruption and absent judgment or condemnation. When applied in an interrogation setting, these approaches have been shown to significantly increase perceived rapport — for example, between interrogators and terrorist subjects, mitigating the subjects’ counterinterrogation strategies and leading to increased information yield.

One conversational-rapport framework that has been shown to increase an interviewer’s ability to establish rapport and to elicit information is comprised of open-ended questions, affirmations, reflections, and summaries (OARS). Open-ended questions are questions that cannot be answered with a brief response or a simple yes or no. When answering these types of questions, subjects are likely to provide longer and more detailed narratives. Next, affirmations are declarations that highlight a subject’s statement, attributes, or experiences in a positive light. This is not flattery; rather it is an authentic attempt to acknowledge something that the subject believes and reflect on it in a positive manner without providing a rationale for a subject’s behavior. Reflections involve repeating short fragments of a subject’s discourse back to them. This simple yet powerful action illustrates both empathy and active listening by using the subject’s own words or phrases. Lastly, summaries involve offering back a concise, yet detailed, encapsulation of what the subject has said and can lead to an array of positive outcomes; summaries demonstrate that the interviewer was listening to the subject and offer them the opportunity to provide a correction. They also provide the opportunity to subtly shift the focus of the conversation and shine a light on discrepancies in a subject’s story in a constructive, non-confrontational manner.

Beyond conversational rapport, certain rapport-building tactics can facilitate relational closeness in an interview setting, including aspects of reciprocal self-disclosure, establishing common ground, and affirming the subject’s identity. Several studies have found support for the efficacy of these tactics to lower resistance in interview settings, leading to more information disclosed. For example, revealing personal information can improve a relationship by increasing liking toward the person disclosing. A well-established phenomenon in the clinical setting, individuals are not only more likely to disclose to people they like, they also find themselves developing a stronger affinity for the person to whom they disclose information (especially when the information is received with respect and empathy).

Because we appreciate people who are similar to us, emphasizing connections can facilitate rapport development and diminish obvious differences between interviewer and subject. Finally, when a subject has self-disclosed, an interviewer can increase rapport by responding in a manner that affirms the subject’s identity. Another approach is to offer feedback that confirms that the interviewer sees the subject as they see themselves. This provides a perspective that is consistent with their own self-concept (and, it should be noted, the feedback does not necessarily need to be positive, it only needs to match the subject’s perspective).

Establishing Trust

Trust is a unique component of a productive relationship that can be explained as a willingness to accept vulnerability, when accepting such vulnerability seems likely to generate a positive outcome. Although prolonged and sustained interactions are typically necessary for a subject to completely trust his or her interrogator, an interrogator can provide a sense of trustworthiness relatively quickly.

At the core of establishing trust is the concept of reciprocity, i.e., the mutual exchange between what is given and received. Reciprocity has been reported as valuable by practitioners and effective at increasing rapport in laboratory research. This central theme is further augmented by the critically important elements of empathy, genuineness, risk, and independence (the subject must perceive the reciprocal interaction as independent of the effort to elicit information).

Two trust-building tactics have been identified by researchers in which interviewers can demonstrate trustworthiness or show a willingness to trust. The interviewer can engage in an action that will make clear that if the person commits to something, then he or she will follow through. For example, if the subject would need their cellphone to contact family, the interviewer can commit to getting them their phone back despite potential bureaucratic roadblocks. The interviewer can also demonstrate a willingness to trust the subject by overtly creating circumstances in which they accept the risk that the subject might not fulfill their obligation. In this case, the interviewer could lend them their own phone to make that call, despite the risk associated with giving them access to such a personal object.

Effective Interviewing 

The demonstrated effectiveness of these evidence-based methods only strengthens the argument against torture and ill-treatment as an unnecessary, unlawful, and morally objectionable option. Moreover, this valuable scientific research provides a firm foundation for the international initiative to develop the Principles on Effective Interviewing for Investigations and Information Gathering via an expert-driven process that includes recognized authorities in law enforcement, counterterrorism, intelligence gathering, psychology, law, and human rights protection. As Otis Cary’s success exemplifies, it is possible to elicit reliable and actionable information without also bending our ethical and legal standards. The time has come to implement more widely these types of successful practices that are now backed by rigorous research.

(A launch event for the Méndez Principles took place on June 9th featuring speakers including U.N. High Commissioner for Human Rights Michelle Bachelet, Deputy Foreign Minister for Multilateral Affairs of Costa Rica Christian Guillermet Fernández, Ambassadors to the U.N. Mona Juul of Norway and Ramses Joseph Cleland of Ghana, U.N. Special Rapporteur on Torture Nils Melzer, and former U.N. Special Rapporteur on Torture Juan E. Méndez. A recording of the event is available here.)

IMAGE: Marines unloading Japanese POW from a submarine returned from war patrol. Ca. May 1945. Lt. Comdr. Horace Bristol. (Navy) Exact Date Shot Unknown (Photo by Department of the Navy, U.S. National Archives and Records Administration, via Wikemedia Commons)