Forensic Psychology For Dummies®

Visit to view this book's cheat sheet.

Table of Contents

Forensic Psychology For Dummies®


About the Author

David Canter drifted into Forensic Psychology in 1986 when he was asked by Scotland Yard to give guidance to a major police investigation into a series of murders and rapes. The value of this guidance opened doors to many other police investigations and brought him into the work of psychologists in many other areas of legal activity. He became a Chartered Forensic Psychologist and developed postgraduate courses recognised by the British Psychological Society as a step towards chartered status. Hundreds of those who were his students now have senior jobs in universities, police forces and many other organisations around the world. He has been a Professor of Psychology at the University of Surrey in the South of England, where he was also Head of the Department, and at The University of Liverpool, where he now has Emeritus status. He is currently Professor of Psychology at the University of Huddersfield where he directs the International Research Centre for Investigative Psychology. He writes for major newspapers, notably The Times, and often contributes to radio and television news and documentary programmes in the UK and overseas. He wrote and presented a six part TV documentary series Mapping Murder that was broadcast around the world.


For Rosie, Robin and Felix in the hope that what is dealt with in this book will always remain irrelevant to them.

Author’s Acknowledgements

The work of many colleagues has been drawn on unashamedly in this book. It is not the For Dummies format to cite these directly. However, I would like to mention that I have found the work of my colleagues Kevin Browne and Donna Youngs, as well as more distant associates Curt and Anne Bartol to be of particular value. Graham Davies reviewed the draft thoroughly and I have incorporated his suggestions, although of course any errors are mine. The compendium put together by Jennifer Brown and the late Elizabeth Campbell, is also a masterwork that I found very useful. Lionel Haward, sadly missed, encouraged me in the early days of my involvement with the law, so his influence is never very far from this book. As ever, I am grateful to my agent, Doreen Montgomery, for her help. My obsession with getting this book written has been endured by Sandra Canter with her love, support and good humour that is taxed every time I take up one of my writing commitments.

Publisher’s Acknowledgments

We’re proud of this book; please send us your comments at . For other comments, please contact our Customer Care Department within the U.S. at 877-762-2974, outside the U.S. at 317-572-3993, or fax 317-572-4002.

Some of the people who helped bring this book to market include the following:

Acquisitions, Editorial, and Vertical Websites

Project Editor: Jo Jones

Commissioning Editor: Claire Ruston

Assistant Editor: Ben Kemble

Development Editor: Andy Finch

Copy Editor: Martin Key

Technical Editor: Graham Davies

Proofreader: Andi Sisodia

Production Manager: Daniel Mersey

Publisher: David Palmer

Cover Photos: © Kitch Bain / Alamy

Cartoons: Rich Tennant ()

Composition Services

Project Coordinator: Kristie Rees

Layout and Graphics: Carl Byers

Proofreader: Lauren Mandelbaum

Indexer: Christine Karpeles

Special Help

Brand Reviewer: Jennifer Bingham

Publishing and Editorial for Consumer Dummies

Kathleen Nebenhaus, Vice President and Executive Publisher

Kristin Ferguson-Wagstaffe, Product Development Director

Ensley Eikenburg, Associate Publisher, Travel

Kelly Regan, Editorial Director, Travel

Publishing for Technology Dummies

Andy Cummings, Vice President and Publisher

Composition Services

Debbie Stailey, Director of Composition Services


I first encountered Professor David Canter’s work and world in a book he published in 1994 called Criminal Shadows. Its subtitle was ‘Inside the Mind of the Serial Killer’, and it interested me because I felt it might help me get beneath the skin of the fictional criminals I was writing about in my ‘Inspector Rebus’ novels. That book was clear-sighted and level-headed. Hannah Arendt had already coined the term ‘the banality of evil’ to describe Nazism and the atrocities which took place in its name. Professor Canter explained that real-life serial killers are seldom like their rococo fictional equivalents. These killers tend towards the banal and colourless; they are lucky rather than preternaturally skilful – and they seldom play complicated mind games with their pursuers.

There is still a place for the likes of Hannibal Lecter in fiction, of course, but he and his ilk belong to the realm of legend and folk-tale. The book you are currently reading will explain why – but it will do a lot more. Professor Canter is an entertaining, comprehensive and comprehensible guide who pricks the myth (perpetuated in film, on TV, and in novels) of the forensic psychologist as a gifted but antisocial loner with drink and relationship problems. In real life, forensic psychologists look at why humans commit crimes and what types of crime they are likely to commit. They also ponder the nature of evil, and whether evil itself can ever be ‘diagnosed’.

In this book you will find a clear explanation of terms such as psychosis, schizophrenia and sadism - terms bandied about in life as in fiction, but not always with any great degree of accuracy.

Professor Canter also looks at the ways in which we can tell if someone is lying, taking in everything from body language to brain-mapping. Forensic psychologists work with various law agencies and may be called upon to help with witness interviews. One of many fascinating cases discussed here concerns a kidnapped bus driver and the use of hypnosis to garner witness evidence.

As a criminal profiler, the author is well-equipped to debunk many of the common misconceptions around that specialism. Profiling can be helpful to the police, but it has to be used with care. Professor Canter cites the case of an attacker who had long fingernails on one of his hands. The investigating officers deduced that they were looking for a guitarist. Had this been a Sherlock Holmes story, they would undoubtedly have been correct, but there was actually another less obvious explanation.

Importantly, Professor David Canter also looks at how forensic psychology can aid victims of crime. Victims are often forgotten about, in life as in fiction. Here they are given due prominence.

Whether you are a serious student or have a casual interest, this book will deepen your knowledge of forensic psychology. I dare say crime writers will find it useful, too, even though we continue to portray our killers as exaggerated monsters with penchants for puzzles, fava beans and a nice chianti.

Ian Rankin


In 1985, a senior police officer at Scotland Yard asked me to attend a meeting to plan an investigation into a series of rapes and murders committed around London. Up until that point during my work as a psychologist, I’d had very little contact with the police or criminals and was rather taken aback when asked whether I ‘could help catch this man before he kills again’. I agreed to assist the investigation and its eventual success changed my life. As a result I was drawn ever more intensively into a wide range of police investigations, and then into commenting on psychological evidence presented in court. I began considering rehabilitation programmes for offenders and examining processes for assessing the possible risk they posed if they were released. I talked to killers and burglars and many other criminals and their victims.

I was now part of the burgeoning field of forensic psychology, reading its journals, giving keynote addresses at conferences, and debating with colleagues and students how many aspects of behavioural science (particularly psychology) were informed by, and carried consequences for, the full range of legal issues. I became increasingly enthusiastic about the evolving ways in which psychology is influencing all aspects of the legal process.

Since that fateful day, I discovered that many people, in all walks of life, have questions about what makes criminals tick, and how psychology can be used throughout the investigation, prosecution, treatment and rehabilitation of criminals and to help their victims. This book aims to answer those questions.

About This Book

In this book, I cover what happens from when a crime is first reported through to dealing with convicted offenders and, where possible, helping them to desist from future criminality. I include many examples of forensic psychology in action to bring the excitement of this professional activity to life.

Here are a few things, however, that you won’t read about in this book: the motives that so delight crime fiction writers (greed, jealousy, revenge . . . in fact I avoid using the vague term ‘motive’ at all); whether criminals did (or didn’t) get on with their mothers; or whether something is wrong with their biology. Instead, Forensic Psychology For Dummies gives you a much wider and more interesting landscape to explore. I go beyond the myths of such popular ideas as ‘offender profiling’ and deeper than whether criminals are born or made. In this book, I show you what forensic psychologists actually do, and why they do it in the ways that they do.

Although psychologists tend to drift into jargon, writing about most of what they do without technical terms is perfectly possible. On the few occasions when specialist words are needed, I make sure that their meaning is clear. So, if you know absolutely nothing of psychology, this book is for you. If you’ve read or studied any psychology before, many aspects are here presented in a new light. If you’ve already had some contact with forensic psychology or are considering it as a career path, the breadth of coverage provides a map to help you find your way.

Forensic psychology is a professional area of activity. So I do describe some of the requirements and challenges that professionalism creates. But even if you’re only curious as to what all the fuss is about, knowing the underlying principles and processes may come in handy if ever you come into contact with a real-life forensic psychologist (they aren’t usually scary, honest).

I think of books in a library as being in conversation with each other, drawing on what they’re about and offering connections for others to pick up. Forensic Psychology For Dummies is part of a gaggle of books chatting to each other. Where you can get more detail elsewhere I make that clear, but bear in mind that I’m using my own point of view to cover what’s written about in other books and, as in any conversation, not everyone agrees with each other. So if you want to check out what others have to say, by all means take a look at Criminology For Dummies by Stephen Briggs (Wiley) and Forensics For Dummies by Douglas P. Lyle (Wiley). Because forensic psychology has such close contacts with the law I mention the legal issues whenever I absolutely have to, but I’m a psychologist not a lawyer. So if you want to get to grips with all that stuff, do what I do and read Law For Dummies by John Ventura (Wiley), although be warned that it’s about the law in the US and every country has its own way of doing legal things. Although the views of criminologists, political scientists, historians and anthropologists, to name just a few, are extremely valuable I don’t engage with these disciplines. This book is about forensic psychology and psychologists focus on individuals and their relationships with others.

Conventions Used in This Book

I use a few conventions to help you find your way around this book easily:

check.png Italic highlights new, often specialist, terms that I always define nearby, and is also sometimes used for emphasis.

check.png Boldfaced text indicates the action part of numbered steps.

Although I keep the number of technical terms and jargon to an absolute minimum, all professional activities include words that have precise meanings for people within that profession. Mastery of these italicised terms enables you to bluff your way in any discussions of crime and criminals.

I try to avoid specific gender stereotyping, but the writing can get very lumpy if I do so all the time. Therefore, every now and then I refer to an individual offender as ‘he’. The fact that the great majority of criminals, 80 per cent or more, are men means that referring to them as male is usually accurate. Of course, this assumption doesn’t mean that women never commit crimes; it just keeps the writing simpler. If I need to refer to specifically female criminals, or make clear that a higher proportion of offenders than normal of a particular crime are female, I do so.

You should also note that a very high proportion of Forensic Psychologists are women, so sometimes it makes sense to refer to them as ‘she’ or ‘her’.

I’d love this book to be a laugh-a-minute, but squeezing humour out of rape and murder, or even the more mundane crimes of burglary and robbery, is difficult if not inappropriate. Criminals themselves aren’t comic (although some of them are clowns). As an expert in court I manage to get a smile out of the jury from time to time, and so whenever I can I do the same here. But please don’t see these attempts to enliven the topic as implying that anything is other than serious.

What You’re Not to Read

One of the problems with most books is that they start at page one and carry on in a straight line until they end on the last page. But ideas don’t always sit along a line so neatly, and often you don’t want to find out about things in the sequence that the writer wants to tell you.

This book is written to take account of such human foibles. In general, each chapter is self-contained and you can read the chapters in any order you like, although the book makes greater sense if you do read chapters in the numbered order. But to help out, I also make any information that you can safely skip easy to recognise. The grey boxes dotted throughout this book (known as sidebars) contain historical examples or more detailed theory that may otherwise break the flow of the text. You can skip them or just flick through to get the feel of what’s going on.

Foolish Assumptions

I’ve lectured on psychology to many different audiences for nearly 50 years (‘it don’t seem a day too long, guv’), which helped me to keep a vision in my mind of you while writing this book. The word Dummies in the title means only that I assume you’re not an expert in forensic psychology, but that you’re intelligent enough to use this book in the way that works best for you. I assume that you have some combination of the following interests:

check.png You’re fascinated by crime and criminals, but want to know more than you can get from fictional accounts or glib documentaries.

check.png You think that you may want to be a forensic psychologist, but are curious as to what it’s all about.

check.png You know a little about the criminal justice system and wonder how the scientific study of people can contribute to it being more effective.

check.png You’re studying psychology and are fed up with artificial laboratory experiments and details of which area of the brain lights up when people do odd things, and so you want to know what psychologists do in the real world.

check.png You’re studying crime or the law, writing an article or book, or making a documentary, and you want to know more about psychology and how it connects with the law.

How This Book Is Organised

Except for the first and last parts, each part of this book deals with a different context in which forensic psychology happens. So you can choose the area that you’re most curious about and start there.

Part I: Nailing Forensic Psychology: A Moving Target

Forensic psychology is a rapidly expanding area and takes on different forms in different places. This part, therefore, gives you an ‘efit’ of forensic psychology to help you recognise it when you stumble across it. Chapter 1 examines what forensic psychologists do (and don’t do) and who they deal with, Chapter 2 describes some of the aspects of what makes someone break the law and Chapter 3 shows how forensic psychology relates to the legal process.

Part II: Helping the Police Solve Crimes

Many fictional accounts of crime investigations use some sort of psychological intervention to help solve the case. In truth, this aspect is a minutely small part of what forensic psychologists do, but it does get the juices flowing and is a crucial point on your journey into the world of forensic psychology.

Getting good information from victims and witnesses during interviews (which I discuss in Chapter 4) isn’t as easy as the movies may have you believe. Not everyone the police talk to tells the truth, and so detecting deception (or indeed bare-faced lying) is a challenging topic, to which I devote Chapter 5. Making use of the information the police do collect opens up the topic often referred to as ‘offender profiling’ (see Chapter 6). Chapter 7 covers the important but often neglected subject of helping the victims of crime and Chapter 8 discusses crime prevention and reduction.

Part III: Measuring the Criminal Mind

Like every science, forensic psychology relies on precise and reliable measurement. But people, especially criminals, aren’t static lumps of material that can be plonked on a laboratory bench to have refined measuring tools applied to them. Therefore, various assessment procedures have been developed to weigh up important characteristics of offenders, such as determining their mental state and its relevance to the legal process, a subject I describe in Chapter 9. A small, but crucial, subset of criminals have no obvious mental problems and are often characterised by commentators as ‘evil’. Chapter 10 looks directly at what this description can mean and offers a less sensational account.

Part IV: Viewing Psychology in Court

Forensic psychology started life as guidance to legal proceedings and is now a common feature of many court hearings. I describe how this process works in Chapter 11. The new developments, especially in the US, of guiding lawyers to be as effective and understandable as possible are covered in Chapter 12.

Part V: Helping and Treating Offenders

Many forensic psychologists end up in prison . . . to help prisoners, of course, and sometimes prison management. Chapter 13 looks at the different forms of psychological help and treatment that are now available for offenders. Two particularly important areas are violence and sex offending, and so they have their own chapters (14 and 15, respectively). Youngsters who become involved in crime pose a particular challenge and so I devote Chapter 16 to them.

Part VI: The Part of Tens

If you want to know more about the professional aspects of forensic psychology, I describe ten vital aspects in Chapter 17. Chapter 18 lists ten stages in the career of many people who become professionals in this area. But because forensic psychology is such a rapidly evolving profession, I also list ten areas that are emerging in Chapter 19. In Chapter 20, I describe ten great examples of cases in which forensic psychology successfully made a significant contribution.

Icons Used in This Book

This book uses different icons to highlight important information. Here’s what they mean:

remember.eps This icon indicates stuff that’s really worth bearing in mind.

mythbuster.eps This icon indicates where I set the record straight on common misconceptions.

anecdote.eps I use this icon to show you where I draw on my own experience to bring you real-life stories.

regionaltipoff.eps This icon tips you off to where I describe differences across the globe or where I focus on one country or jurisdiction.

strangebuttrue_weddings.eps This icon reveals unusual nuggets from the realms of criminal investigation and behaviour.

Where to Go from Here

You can read this book in any order you like, because I write it so that the text makes sense wherever you start. You can flick through and look at the cartoons (which to be honest is how I explore For Dummies books) or just go straight to the Part of Tens for some useful summaries. But if you’re new to the subject, I think you’ll get more out of it if you read Chapter 1 first. Most importantly, though, enjoy!

Part I

Nailing Forensic Psychology: A Moving Target


In this part . . .

The work done by forensic psychologists covers an increasingly wide range of topics; everything from exploring how to detect deception and malingering all the way through to helping families who have juvenile delinquents in their midst. Other examples are helping witnesses to remember and assessing how dangerous a person really is. These professional contributions occur in many different institutions: law courts, prisons, special secure hospitals for people sent there by the courts, in the community at large and on rare occasions even as part of police investigations. They concern themselves with all sorts of criminals from arsonists to terrorists and crimes starting with every letter of the alphabet in between.

At the heart of what forensic psychologists do is an understanding of criminals, their actions and the causes of their behaviour. This links to many other people who are interested in criminals such as criminologists, lawyers and even doctors and geographers. The difference is that psychologists focus on the person rather than patterns of crime, with that person’s thoughts and emotions rather than physical or sociological processes. To get started, there is a lot of ground to clear about what forensic psychology is and the basis of what forensic psychologists do. In this part, I map out the fundamentals to get you ready for the more detailed stuff later.