Researcher Robin Kranendonk defends her doctoral thesis

Recognising and interviewing suspects with a mild mental disability. This is the topic of the doctoral research Robin Kranendonk completed yesterday with her defence at Vrije Universiteit Amsterdam (VU). Robin is a criminologist and works as a researcher at the Netherlands Police Academy and the Netherlands Institute for the Study of Crime and Law Enforcement (NSCR). Suspects with a mild mental disability have a high chance that their disability is not recognised during police interviews. This impacts the way in which the interview is conducted. This is one of the conclusions drawn in Robin’s study.

In the past, Robin worked with vulnerable persons, including people distanced from the labour market due to psychological or physical problems. She also studied many interviews and examined the contents of official reports of police interviews.

The Amsterdam Law and Behavior Institute (A-LAB) offered Robin the opportunity to conduct research. A-LAB is a collaboration between the VU and the NSCR. In the context of her research, Robin studied the risks involved in recognising and interviewing suspects with a mild mental disability by the police. She also looked at protective factors to mitigate these risks, such as asking open questions and an attorney being present. ‘For me, this study brought together my interests in vulnerable persons and police interviews. I want to contribute to knowledge building on this important topic. I also appreciated the opportunity to deep dive into interviewing practice’, Robin says.

In the interviewing room

Since 2017, Robin had been conducting a literature study. She interviewed experts knowledgeable in recognising and interacting with people with a mild mental disability. She also interviewed criminal investigators, public prosecutors and attorneys. Robin: ‘I specifically asked them how they think they can recognise mild mental disabilities. And what they think is important in communicating with this group of people. Finally, I asked them how they think an interviewer can obtain the correct information and how this is done in practice. These interviews provided me with a picture of all possible risks, bottlenecks and protective factors in recognising vulnerabilities. And of ‘what works’ in obtaining correct and complete information.’

In the second phase of her study, Robin spent much time in the interviewing room. In preparation, she developed a coding system based on information obtained from literature and the interviews she conducted. She observed interviews in which the interviewers knew beforehand that the suspect had a mild mental disability. These often involved more serious criminal offences. In most cases, the interviewers had completed a specialist training programme for interviewing vulnerable suspects. Robin also observed officers from various police units. The interviews they conducted were often about frequently occurring crimes, such as theft and domestic violence. Most of the police interviewers in these frontline teams had not completed any specialist interviewing training programmes.

Important personal conversation

‘I looked at the extent to which interviewers made an effort to recognise a psychological vulnerability at the start of the interview. To do so, I analysed what questions they asked on certain topics from the Indications of Vulnerability Questionnaire included in the Interviewing Handbook’, Robin explains. When there was prior knowledge of a mild mental disability or mental illness, trained interviewers brought up more personal topics that could help them recognise vulnerability, including education and support by care professionals. They also asked more in-depth questions in relation to this.

Police interviewers with basic training and no prior knowledge of mild mental disabilities in the suspect tended to focus on more general topics, such as employment and debts. They asked less in-depth questions and seemed less aware of possible vulnerabilities. This may result in a mild mental disability being overlooked. But what are the indicators that point to a mild mental disability? These include support by care professionals, having attended special-needs education or daytime activity groups, or receiving benefits. Further indications may be that the person fails to understand procedures, their rights or the questions asked.

Vulnerabilities often go unnoticed during police interviews

Robin: ‘In 4 per cent of the suspects of frequently occurring crime studied (73 persons) there was prior knowledge of a vulnerability. Yet, my study found that 44 per cent showed clear signs of a mild mental disability. And in 52 per cent of cases, a mild mental disability or mental illness was suspected. Without the interviewers being aware of this before the interview started.’

Why do vulnerabilities go unnoticed so often? Robin believes the people affected are often very good at hiding them. ‘Shame plays a role in this. Some ‘streetwise’ suspects copy the language they’ve heard their care professionals use, for example. This allows them to come across as verbally strong, while they don’t really understand what they’re saying. This group may seem uninterested, defiant or aggressive. Not because they don’t want to cooperate, but because they don’t understand the situation they’re in. This behaviour is often seen as suspect or uncooperative. Other persons may seem very cooperative, which may also be misleading.’

‘A lack of information sharing between organisations, attorneys and the police can further complicate recognising suspects as vulnerable. The same goes for a lack of preparation before the interview. This poses risks. When a mild mental disability is not recognised, suspects are often subjected to a standard interviewing approach, without protective measures. For example, 74 per cent of suspects with a suspected mild mental disability did not have an attorney present at the interview. They may waive their right to an attorney, simply because they do not understand what it means. This can have serious consequences for the legal position of suspects.’

Incorrect statements and false confessions

‘When was it? How often did it happen? Who were you with?’. Suspects with a mild mental disability sometimes struggle to answer these questions. They have a hard time remembering such details. Additionally, they often struggle to find the right words, which may lead to miscommunications. Moreover, they tend to have a strong urge to please others. They easily take on suggestions and sometimes even confess to criminal offences for which they have not been arrested. It increases the risk of incomplete, incorrect or unintended incriminating statements.

In the worst case, it may even lead to false confessions. ‘Suspects believe they’ll be allowed to go home sooner, for example, but they don’t understand the consequences. As a result, they may not get access to appropriate help and protective measures. Furthermore, there’s a risk of less efficient criminal investigations, incorrect settlements, and repeat offences. So, a tailored interviewing approach is of the essence’, Robin argues.

Uniform approach when there are signs of a mild mental disability

But do interviewers actually adapt their approach when there are signs of a mild mental disability? To answer this question, Robin compared three groups of suspects. In the first group, there was prior knowledge of the suspect’s mild mental disability. In the second group, researchers suspected mild mental disabilities. And in the last group, no indications of mild mental disabilities were observed. ‘We looked at the types of questions asked, the interviewing techniques used, and the statements obtained.’

‘There were few differences in interviewing technique between suspects with and without indications of a mild mental disability. This may mean that interviewers with basic training missed the signs. Or were unsure or unwilling to adapt their interviewing approach. This study shows the effect of training on and prior knowledge of mild mental disabilities. Interviewers with relevant specialist training, paid more attention to explaining the suspect’s rights and to building rapport. They also used simpler language and fewer confrontational techniques.’

Proven, effective interviewing techniques

‘In every interview, it is important that suspects tell their own story. Without being influenced by how the questions are formulated. Otherwise, the answers to the questions tend to be very short. Open questions such as ‘tell me all about …, can you describe …, please explain …, what happened next?’ work well. Active listening, verifying answers and summarising what was said are other important techniques’, Robin explains.

This approach is in line with international guidelines, such as the Méndez Principles on Effective Interviewing for Investigations and Information Gathering. These Principles are a global protocol drawn up by the United Nations for effective interviewing without using pressure or force. It safeguards the rights of suspects. The protocol was also subscribed to by the Dutch authorities and can be applied in all types of interviews.

People with a mild mental disability tend to provide less information when they’re asked open questions. ‘But what you do get, is their own story, uncoloured by the interviewer’s suggestions’, Robin says. ‘It’s also important to be cautious when using ‘prompting techniques’, such as providing examples or complimenting the statements. They may yield more information, but you cannot be sure this information is correct.’

Concrete steps

‘My study offers concrete suggestions for the police, attorneys, public prosecutors and judges. How can you recognise a suspect with a mild mental disability? How do you interview such suspects effectively and according to the rules? And how can you limit risks?’. The study also provides examples from police practice and fragments of actual interviews. These insights can be applied directly to basic police training and specialist training modules. They apply to interviews with suspects, but also with victims and witnesses.

‘I wrote a detailed book in English. Together with the police organisation and the educational field, I’d like to put theory into practice. Maybe it’s possible to develop additional e-learning modules, virtual reality training or practical tools. For example, a poster on which all steps are explained clearly and visually. Such as: what should I look out for? What should I do if I suspect a vulnerability? Should I call in a specialist interviewer? I’d like to explain these concrete steps, so interviewers know what to do.’

Photography: Laurens Niezen