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Q&A: DeMatteo Discusses Groundbreaking Handbook on Psychology and Law

Professor David DeMatteo

September 29, 2023

Professor David DeMatteo, director of Drexel University’s JD-PhD in Law and Clinical Psychology, co-edited The Oxford Handbook of Psychology and Law with Kyle C. Scherr of Central Michigan University. Oxford University Press published the book in February 2023.

A Professor of Law at the Kline School of Law and a Professor of Psychology in the Department of Psychological and Brain Science, DeMatteo is a leader in mental health law and a prolific scholar whose research interests include psychopathic personality, forensic mental health assessment and offender diversion. His research has been funded by numerous federal and state agencies, as well as private foundations.

During an interview DeMatteo spoke about the growing field of psychology-law and the value of bringing together authors from the clinical and experimental sides of psychology-law in the new book.

The Oxford Handbook of Psychology and Law

How would you characterize this book?

I work within this field of psychology and law; it’s sometimes referred to as forensic psychology. And there are two distinct disciplines in the field. There’s the clinical forensic psychology, which is doing evaluations of justice-involved people and offering testimony in court and going into jails and prisons and that sort of thing, sometimes doing therapy with people who are incarcerated. And then there’s the experimental side of forensic psychology, which is the pure research component of investigating topics that are relevant to the legal system, whether it’s the reliability of eyewitness testimony or violence risk factors, and these fields are both contributing to our understanding of psychology and law, but there hasn’t been a comprehensive book that brought those two fields together. I wanted to sort of blur that relatively arbitrary line between those two fields. So that was the impetus for the book.

Who is your intended audience?

The goal was to provide this comprehensive resource … for students, early-career professionals, seasoned-career professionals …Primarily, the book is geared toward forensic mental health professionals—psychologists, psychiatrists who work in that intersection of psychology and law. We did have lawyers contribute to the book. I think that some of the chapters would be very relevant in informing lawyers to help them improve their practice

And if legislators were to review this book, there’s lots of things in there about how policy could be changed based on social science evidence. We have, not surprisingly, a lot of outdated laws that are not very informed when it comes to certain topics for which mental health is relevant, and so hopefully we’ll have people who are in the right positions who could read this book and consider some of this information when they’re making changes.

Can you say more about how the book might be used by law professors and students?

It bridges the gap between psychology and law. My career has been about bridging that gap and increasing the communication between those two fields. Part of the idea with this book was that legal professionals—lawyers, law students—could look at this book and it would give them an understanding of the value of forensic psychology, the value of what we do as a field, which ultimately is going to inform and improve their practice in law.

What is most unusual about this book?

The mix of chapters on both the clinical and experimental sides. We included five foundational chapters upfront that intentionally blur the lines between these two areas because I never really liked the distinction between them…Some people are really rigid about which side they fall on, so we included these foundational chapters to intentionally blur that distinction. And we asked each chapter author to blur that distinction toward the end of their chapter. I think those are some of the unique aspects of the book.

You say in your preface, “The field of psychology–law has grown considerably over the past few decades.” Why is that the case?

Number one, more students and laypeople are just becoming interested in forensic psychology. There are TV shows and movies about some aspect of forensic psychology. There are a lot of true crime shows, and a lot of times they interview, in addition to law enforcement, mental health professionals to talk about these things. We’ve seen an increase in the number of training programs across the United States in forensic psychology, both at the undergraduate and graduate level, and I think part of what’s driving this is that the legal system is increasingly recognizing that psychology has something to offer, that we in individual cases can help the judge and the jury understand insanity or competence or these issues that are legal questions that involve mental health, so courts are starting to call upon us and rely on what we do. Related to that, legislators, policymakers, are increasingly paying attention to the research that we do.

So I think if you look at all of those things, they’ve contributed to the growth of the field. …There are multiple journals that address forensic psychology; there are professional organizations that focus exclusively on this relationship between psychology and law, both national and international; there are conferences that address this; and just anecdotally I can tell you that I get emails every week from people across the country wanting to know how to get into this field.

What current issues or trends does the book touch on?

One is the increasing overlap with brain science when it comes to forensic psychology. There's a lot of focus in academic units on brain science in psychology. Drexel, as a case in point, recently changed our name from Department of Psychology to the Department of Psychological and Brain Sciences, and a lot of universities have been following that approach. When you poll high school kids about what they want in psychology training, a big thing that comes up is, they want the brain science–they want to learn more about that. We’re seeing increasing involvement of neuropsychology in forensic arenas, so that’s one of the big developments, and we have some chapters in the book that talk about that.

The other one I would say is an increased focus on diversity. We’re far from perfect, of course, but we are, as a field, becoming more aware of the limitations of our techniques that we’ve been using for decades when it comes to people of other cultures. … There are multiple chapters in the book that address diversity, how that plays into a particular topic area.

Why did you feel this project was important?

I value time—my time, author time–and I did not want to do another edited book that did not make a contribution to the field. I thought this project had the potential to push the field forward in a meaningful way, even if it’s just incremental. But [we wanted] to get people to realize that we’re all one field and we all have the same goal about informing policy and practice using psychology and social science evidence. To me that felt like a worthwhile goal for both the mental health people and the legal people, and that’s why I wanted to do it.

There are other handbooks of forensic psychology…but I do believe this is the first one, in the way we did it, that really draws together both big aspects of the field of forensic psychology. And we not only got really outstanding, all-star authors for this book—I think we had 114 or 115 co-authors altogether—but we also targeted people from underrepresented groups who typically don’t get the opportunity to publish as much, and we targeted early-career professionals…. So having that mix of established people and up-and-coming people and underrepresented groups, I also think makes a valuable contribution to the field.

This interview was edited for brevity and clarity.