Science-Based Interviewing: The Power of Open-Ended Questions and Nodding

In the world of science-based interviewing, certain techniques can significantly influence the effectiveness of your interviews and interrogations. Among these, there are many variations; one of the most prominent ones is asking open-ended questions coupled with nodding your head. Research supports the use of these questioning strategies, demonstrating how they contribute to the information supremacy philosophy, which means not only more information but also better quality information elicited during your interviews.

Open-Ended Questions: An Opening to Understanding

Open-ended questions are an incredible tool in any interview. They allow respondents to provide a narrative response in their own words rather than picking from a predetermined list of answer choices (leading questions), which can restrict the length of their answers. Pew Research Center notes the power of open-ended questions through an example from the 2008 presidential election. When respondents were explicitly offered "the economy" as a response option, over half chose it. Yet, when asked the same question in an open-ended format, only 35% mentioned the economy. Importantly, 43% of those who responded to the open-ended question gave a response not listed in the closed-ended version, highlighting the capacity of open-ended questions to reveal unanticipated perspectives and insights (Pew Research Center, n.d.).

Open-ended questions make science-based interviewing work better.

Open-ended questions make science-based interviewing work better as well. Field research has shown that open-ended questions elicit responses that are significantly longer and more informative—on average, six times longer than probing questions and nine times longer than closed yes–no questions. Despite their power, open-ended questions made up less than 1% of all questions asked in a study of real police interviews and were completely absent in over 60% of the interviews analyzed (Snook et al., 2012).

This election example translates directly to the interview and interrogation room: when you rely solely on closed, confirmatory, or leading questions, you risk boxing the person into predefined narratives, often your own predefined narratives (confirmation bias), ones you’ve already imagined or assumed. On the other hand, when you use open-ended questions, you step into a mode of discovery. This is where the "unknown-unknowns" live—those pieces of information that aren’t just missing but entirely outside your frame of reference until the interviewee brings them forward. It’s in this space that skilled investigators thrive, not by confirming what they think they know, but by learning what they didn’t even realize they needed to ask. This is apex curiosity. Each unexpected detail will reshape your understanding of the situation, sharpen your follow-up questions, often unlock entirely new lines of inquiry, and allow you to make more informed investigative decisions.

Curious investigators ignite their information-laden investigations by asking open-ended questions that don’t just fill in gaps; they uncover what no one even knew to look for. It’s where elite investigators separate themselves from the routine ranks. Open-ended questions ignite the process of deep discovery. If it's really about justice, it can't be about confirming your beliefs; it must be about finding the truth. You should demonstrate your commitment to truth and justice not in your marketing, but during the interview process. In action.

Nodding: An Active Listening Affirmation

While the words we use in conversation carry explicit meaning, our nonverbal cues also communicate volumes. Among these, the simple act of nodding, an immediacy behavior, can have a profound impact on the dynamics of a conversation. Head movements, including nodding, are integral to human speech. Casual observation reveals that both speakers and listeners use nodding as a form of backchannel feedback, coordinating it with other forms of gesticulation, like hand and facial movements.

Head movements are sensitive to speech rate and affect and can serve several functions. Speakers use them to structure discourse, indicate lexical repair, and signal a turn-taking shift, among other functions. Furthermore, head movements are tied to the motoric consequences of speech production. During speaking turns, "the head moved almost incessantly," with nearly 90% of recorded frames showing non-zero velocity. This contrasts with relatively little movement during pauses and listening turns, illustrating how head movements, including nodding, are closely linked with active engagement in a conversation (Hadar, Steiner, & Rose, 1983).

In the context of interview and interrogation, nodding takes on additional weight—not just as a natural gesture, but as a strategic cue. Fast nodding, in particular, serves as a nonverbal backchannel that signals to the speaker that you are listening, engaged, and receptive. This is especially powerful when paired with open-ended questions, which are designed to draw out unanticipated, detailed narratives. Research shows that fast nodding is most likely to appear when new information is being exchanged, reinforcing its role as a behavioral marker of attentiveness and information processing in real-time dialogue (Falk et al., 2023).

In wrapping up, open-ended questions and nodding are a powerful combination of active listening techniques supported by research and employed by great interviewers. Open-ended questions elicit rich, detailed responses, while nodding—especially when used deliberately—provides nonverbal affirmation and encourages further disclosure. Whether you're conducting an interview, having a casual conversation, or engaging in a challenging negotiation, integrating these strategies can significantly enhance your communication effectiveness. These are just two small pieces of science-based interviewing. Check out one of our events that may be coming near you soon—or reach out to schedule a private session for your team to learn more about what science-based interviewing can do for your investigations, whether criminal, human resources, compliance, corporate, or otherwise. Stay curious!

Falk, P., Cañigueral, R., Ward, J. A., & de C. Hamilton, A. F. (2023). Head nodding and hand coordination across dyads in different conversational contexts. https://doi.org/10.21203/rs.3.rs-3526068/v1

Hadar, U., Steiner, T. J., & Rose, F. C. (1983). Head movement during listening turns in conversation. Journal of Nonverbal Behavior, 8(4), 214–228. https://doi.org/10.1007/BF00987219.

Pew Research Center. (n.d.). Writing Survey Questions. Retrieved from https://www.pewresearch.org/methods/u-s-survey-research/questionnaire-design 

Snook, B., Luther, K., Quinlan, H., & Milne, R. (2012). Let ’em talk! A field study of police questioning practices of suspects and accused persons. Criminal Justice and Behavior, 39(10), 1328–1339. https://doi.org/10.1177/0093854812449216