The Real-World Applications of Investigative Interviewing Research

Reviewed by Dr. Dana Hirn Mueller

investigative interviewingA shirt color. A peculiar scar. A half-remembered license plate number. Any one of these details can turn a dead-end investigation into an open-and-shut case. Detectives start mining memories for these little golden nuggets in the earliest and arguably most important part of any criminal investigation: the investigative interviewing of witnesses and victims.

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Unfortunately, though, mistakes can happen in interviews. It happens all the time. And often with life-ending consequences.

According to the Innocence Project, a non-profit focused on holding the criminal justice system accountable for its failings, about 400 convictions to date have been overturned by DNA evidence. 69% of those wrongful convictions were the result of eyewitness mistakes — inaccurate memories gathered during interviews and accepted as truth during court proceedings.

These startling statistics beg the question, how can police forces, lawyers, insurance companies, and the criminal justice system as a whole better separate fact from fiction?

According to professor and experimental legal psychologist Dana Hirn Mueller of  Concordia University, St. Paul's Department of Psychology and Family Science, the answer is two-fold. She says there needs to be more research about interview techniques and more communication about that research outside of the academic arena.

“One thing that I noticed as I was coming up through graduate school is that we do research in our ivory tower,” she said in an interview with “This means that it doesn't often reach the practitioners for whom this research may actually be of benefit.”

But what does a psychologically-sound, science-backed investigative interview actually look like? And more to Professor Hirn Mueller’s point, do the nation’s law enforcement agencies know how to conduct such interviews? If not, how should law enforcement officials and psychology researchers bridge the gap? had the pleasure of learning more about topics in the field from Dr. Dana Hirn Mueller, Assistant Professor of Psychology at Concordia University, St. Paul. As an experimental and legal psychologist, a great deal of her scholarship has focused on ways to integrate psychological research with legal practice. Additionally, her central research interests concentrate on improving psychology curriculum at the undergraduate level, promoting undergrad research, and teaching.


Investigative Interviewing: The Good, the Bad, and the Reality

Using Psychological Research and Data To Create a More Just World


Investigative Interviewing: The Good, the Bad, and the Reality

Crimes are unexpected, happen fast, and often overwhelm the senses. As such, recalling details about a crime isn’t always straightforward. According to Professor Hirn Mueller, a productive investigative interviewer keeps this in mind and acts accordingly.

“When I talk with students about this, I try to get them to think about what would impact your recall in particular,” she says. “So if you have just witnessed, for example, a car accident, what might make you more likely to remember details of it? What might make you less likely to remember details?”

Professor Hirn Mueller and her colleagues explored these questions in a 2015 paper published in peer-reviewed journal Psychology, Public Policy, and Law. The study starts off by introducing readers to some investigative interviewing best practices. Each one comes backed by years of psychological research and is recommended by the NIJ (National Institute of Justice). The measures focus on:

  • Asking open-ended questions.
  • Utilizing context reinstatement to jog witnesses’ memories.
  • Communicating expectations about the level of detail interviewees should give.
  • Building positive rapports with witnesses and victims.
  • Facilitating nonverbal response options like drawing.

Together, these techniques make practical and theoretical sense. They discourage witnesses from answering questions about details they didn’t notice, encourage accurate recall, and generally put interviewees at ease with a sometimes painful, emotional process.

But the purpose of Professor Hirn Mueller and her colleagues’ research wasn’t to simply collect research-based guidelines about investigative interviewing. It was, in part, to determine how many law enforcement officers follow them and how often they use them in relation to counterproductive interview tactics.

The responses were, at best, mixed.

Examples and Effects of Counterproductive Interview Techniques

For every productive interview practice, there’s at least one non-productive or even counterproductive technique. Instead of open-ended questions, interviewers may ask stilted yes/no questions. They may even build a negative rapport with witnesses and make the interview needlessly tense. Or to collect information quickly, an interviewer may ask multiple, complex questions at once, overwhelming the witness and clouding their memory.

But perhaps one of the most dangerous counterproductive interview techniques is asking leading questions. A 1974 study on memory called the Loftus and Palmer Experiment demonstrates why.

In the experiment, participants were shown footage of two cars getting in a wreck. Some participants were asked, “About how fast were the cars going when they smashed into each other?” Others were asked the same question except the word “smashed” was replaced with hit, bumped, or collided.

A week later, participants were asked if they remembered seeing any broken glass at the scene of the accident. Participants who were asked the “smashed” version of the question were much more likely to say yes even though there was no broken glass present.

This goes to show that a single suggestive word can alter a witness’s memory recall. So even if detectives or other interviewers don’t intend to ask leading questions, when they do, they can make investigative interviews fertile soil for misinformation — misinformation that sprouts unintentionally dishonest testimonies and false confessions that end lives.

The Prevalence of Bad Investigative Interview Practices

Professor Hirn Mueller and her colleagues contacted an astounding 1,682 law enforcement departments across all 50 states. 271 individual officers consented to partaking in their electronic survey. 59 officers entered only personal demographic data or nothing at all, leaving them with 212 participants.

Not every participant answered every question, but the researchers asked them to:

  • Identify interview techniques in short video segments. Some were recommended techniques while others were counterproductive.
  • Report how often they used each technique.
  • Rate the effectiveness of each technique.
  • Report how many hours and what kind of training (lecture, reading, practice, etc.) they received in cooperative witness interview techniques.
  • Communicate if they were aware of research-based interview guidelines as provided by the NIJ.

“Encouragingly,” the researchers write, “out of those investigators who responded, most

demonstrated a reasonably good understanding of and distinction between productive techniques and counterproductive techniques.”

Professor Hirn Mueller and her fellow researchers also note that participants generally rated productive interview techniques as better at, “eliciting both accurate and plentiful information compared with counterproductive techniques.”

Despite this fact, participants reported using counterproductive interview techniques in 42% of their interviews. To highlight a couple, 71.4% said they used yes/no questions and 32.1% reported building negative rapports with interviewees. Many officers who use these techniques say they do so because they, like recommended techniques, elicit accurate and plentiful information.

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However, the intro of Professor Hirn Mueller’s paper cites multiple studies that highlight why these counterproductive techniques are, in fact, counterproductive (they confuse witnesses, alter their memories, encourage limited responses, etc.). So even though there’s plenty of scientific data out there about why officers should avoid certain interview techniques, those techniques are still being used to the detriment of countless innocent people and victims.

Therein lies the driving force behind Professor Hirn Mueller’s work and passion for psychology: making academic research more practical and accessible to people who can actually use it.

Using Psychological Research and Data To Create a More Just World

“What typically happens is we do our research,” Professor Hirn Mueller says, “and we present it at a conference that's attended primarily by legal psychology researchers. Or, we publish in a peer-reviewed journal that's primarily only consumed by other legal psychology researchers.”

That’s the insular cycle Professor Hirn Mueller wants to break with her practically-minded approach to psychology, an approach students pursuing any level of psychology degree can find purpose in.

“One thing that I try to do in my research, or at least to be mindful of, is to bridge that gap between research and practice,” she says. “In other words, how can we take what we learn in our research and help to apply that in actual practice?”

In keeping with this goal, Professor Hirn Mueller and her colleagues end their paper with a discussion about how they can cooperate with law enforcement agencies to make effective, scientific interview practices more common:

  • Ensure the distribution of NIJ guidelines. In their research, Professor Hirn Mueller and her colleagues discovered that only 2.3% of participants said they had both received and been mandated to follow these guidelines.
  • Make interview training more central to police academy curriculum. On average, participants in this study only received about five hours of interview training during their police academy education.
  • Implement continuous interview supervision and feedback. Even when law enforcement officers receive adequate training, they may need help avoiding counterproductive techniques throughout their long, varied, and often intense careers.
  • Distribute additional research and information. Along with NIJ guidelines, up-to-date research should be distributed, discussed, and put to use amongst law enforcement agencies. Ideally, relevant statistics would be shared by trusted sources within the law enforcement community itself instead of coming from some far-flung ivory tower.

When these things happen, fewer innocent people may have their lives ruined by court rulings based on inaccurate yet convenient information. Victims can get closure. Justice can be justice, fueled not by emotion and fallible instincts, but by research, data, and uncompromised truth.

This exciting union of academia and applied psychology doesn’t end with the criminal justice system, either. Social workers can use memory-focused research to help clients through volatile, searingly painful experiences. Executives in any industry can use it to form hiring practices that truly find the best person for the job.

“One thing that I try to convey is that because psychology is such a wide-ranging field, it really has facets in virtually every area of our everyday lives,” Professor Hirn Mueller says. “I really try to foster the idea within our students that even if they're not interested in actually pursuing a career in psychology, that it can impact not only their professional lives but their personal lives, as well.”

At every level, more psychological research on memory (and more discussion of it) stands to improve how our world operates and how the people in it understand each other and themselves — a prospect students can use to fuel their own research and launch rewarding, people-centered careers in psychology.