Forensic Psychology: Interviewing Suspects of Serious Crimes

Forensic Psychology: Interviewing Suspects of Serious Crimes

In early March, PaCCS Communications Officer Kate McNeil sat down with the University of Derby’s Professor Ray Bull to discuss his work on D-SCENT: Raising challenges to deception attempts using data scent trails. Here, his work focused on exploring the tools for interviewing used to produce clear evidence for arrests and prosecutions. This project was funded by the EPSRC, ESRC, AHRC and CPNI, and was designated as falling under the Global Uncertainties Umbrella. While the project began in 2007, the data produced during the study are still resulting in new findings and new papers even more than a decade later.

Kate McNeil: Thank you for taking the time to chat with me today! Would you mind getting started by telling me about how you ended up doing work on interviewing tactics for suspected terrorists?

Professor Ray Bull: I’m a forensic psychologist by training, and over recent  decades I have been conducting research on and with police organisations. That work on psychology and policing really began in the 1980s, when I was the lead author on a pioneering book called Psychology for Police Officers.

After that, I worked on issues related to investigative interviewing – the interviewing of suspects, witnesses and victims of crime in an ethical, non-coercive way. Throughout the late 80s and early 90s, I was asked by the Government to work with a law professor to draft what became the official government advice on how to best interview children who may have witnessed crimes or been the victims of crime. At around the same time, I became involved in knowledge translation – sharing the findings of psychological studies with a committee of senior police officers who were writing national guidance on what has come to be called the PEACE method of police interviewing, and I was also part of the team commissioned by government to write the official guidance on how to interview vulnerable people.

Those experiences helped to inform my understanding and gave me a solid foundation off which to begin an investigation into how to best interview suspects and witnesses of serious crimes such as terrorism.

What did the D-SCENT project involve in practice?

We conducted two substantial studies on strategic approaches to police interviewing. There are three main approaches used for police interviewing – early disclosure where police reveal everything they already know at the beginning; gradual disclosure, which is the incremental disclosing of information throughout the interview and the holding of some information back; and the  late disclosure approach pioneered in Sweden, where you only give away what you know at the end of the interview and then allow the suspect the opportunity to respond to what you know. We wanted to know which approach was most effective, and particularly whether police should reveal information that might not be in and of itself incriminating until the person says something to the contrary.

In the first study, we had 120 people take part in a mock terrorism crime, and then had an ex-police officer who had also held a PhD in a relevant area of psychology interview the suspects, while the interviews were filmed for observers. Here, we learned that the gradual disclosure interview approach enabled people who watched the recoded interviews better able to detect deception – and some of those observers were police officers.

In the second study, we had five senior detectives spend their free time conducting the interviewing of the suspects  of this mock terrorism, and after the interviews they had to decide whether people had committed acts of terrorism or whether they had committed similar acts that were  innocent. Here as well, we found that those police officers were better able to detect deception using the gradual disclosure approach. We’re now analysing more of the data to see whether, as was the case in the first study, people observing recordings of the interviews are also able to make better judgements about deception when this approach is used.

I’m surprised that you’re still analysing this data! Was this all planned from the start, or has the project built over time?

It’s built up over time. We initially completed the work we had said we would in our funding proposal, but both myself and another professor who was previously a postdoc on the project have continued to look at the data that wasn’t part of the main proposal. As we’ve disseminated the findings of the initial research, we received feedback from people asking about whether we did or could do other things with the data, and we’ve tried where possible to then take that feedback and run with it.

For example, we’re presently writing up a piece focused on interview recordings because in a number of countries, including in England and Wales, it is very common to record when interviewing  suspects of serious crimes like terrorism, and to have an interview advisor watching. 

How does this project fit with what you’ve been working on since?

Both myself and the postdoc who worked with me on this project (Professor Coral Dando) have since been invited to a variety of places around the world to update senior investigators on recent findings in psychological research which might be able to help them improve their training. The findings of the D-SCENT project are part of what we share when we go and talk around the world about these issues.

Have you encountered a lot of different ways of doing policing as you’ve travelled around?

Yes, but there’s been a big turning point around the world which has been led, for historical reasons, by the police in England. When interviewing terrorism suspects there are two main ways of doing it – the old-style, American coercive way, or the peaceful, relaxed humane way. And at last several countries are moving away from the traditional coercive approach and are interested in learning more about ethical investigative interviewing.

I’ve worked in more than 30 countries now, and it’s wonderful to see countries becoming more open minded. Places which used to take the view that nobody who is planning or has committed a serious crime like terrorism will ever tell you the truth are now changing tactics. The PEACE method, to which psychologists like me contributed, is becoming more popular.

All the research around the world now shows that if you use these peaceful investigative interviewing techniques, more suspected persons will tell you the truth than would have been the case if you coerced them. And there’s increasing awareness amongst policymakers and professionals that coercive approaches and torture-based approaches to interviewing or interrogation aren’t just inhumane, they also are less effective.

What’s it been like, working at a knowledge translation interface with police officers? Did you have to adjust your thinking to engage in effective two-way dialogue?

I’ve always believed in working with organisations, and the main one I’ve worked with over my career is the police. I think that as a university researcher, one should ask the professionals what their needs are, what their strengths and weaknesses are, how we can help, etc.. Obviously, that wouldn’t be the totality of the reasons for doing research, but it helps to design work that is likely to have impact, and which is likely to be well received.

Historically in the UK, many researchers saw their role as telling professionals what they should be doing in a one-sided conversation, and the professionals would then react negatively to that – as anyone would. In many countries, there’s still that lack of dialogue between universities and organisations such as the police, so as I go around and talk to people in other countries, I always recommend starting a two-way dialogue. It can be so helpful to understand the beliefs, opinions and problems faced by the people whom you are researching.

Do you have any other key messages for policymakers and police forces?

The crucial thing, which seems so obvious, is that when a suspect is being interviewed or interrogated, the professionals conducting that process have to be open minded. It’s possible that this suspect is innocent or is significantly more or less involved in the crime than you suspect. You have to be open to a variety of possibilities, and of course humans find it difficult to be open minded. The PEACE method tells you how to be open minded, and how not to base your decisions on weird behaviour like “oh, that person scratched their nose, so they must be lying.” That’s a load of rubbish. You need to concentrate on what the person says and compare it with what you know, and that’s the crucial basis of the recommendations we make to policymakers.

I also think it’s important to recognize that interviewing someone suspected of a serious crime such as terrorism and getting relevant information in an ethical way is a very high-level skill. It’s time consuming, and it’s not easy to do. In the old days, a lot of politicians and senior police wanted interviews to be done quickly, but if you do this quickly, you don’t get good information. It’s like a lot of things in life – doing it properly takes time.

I’ve also been working as part of a committee of 15 people involving the retiring UN Special Rapporteur on Torture which is producing a worldwide guidance document on how to interview suspects. The recommendations we’ll be making are grounded in an approach which is very similar to the PEACE method. We’re nearly finished writing this guidance document, and it is planned that it will eventually be made available to all UN member states. When that’s published, I think it will be a very important read for policymakers and police forces – so stay tuned.