What Is the Forensic Psychology of Deception? A Forensic and Criminal Psychology Podcast Episode

Whenever we think about professional lie detectors, we tend to think about the “experts” we see in crime dramas. The sort of people who can expertly and instantly tell if a person is telling or not, and some people claim to be able to do this in real life. Is there any truth in this claim? In this forensic psychology podcast episode, you’ll learn about the forensic psychology of deception, how lie detection works and why psychology is interested in lie detection and more. If you enjoy learning about criminal behaviour, deception and applied psychology then this is a brilliant episode for you.

Today’s criminal psychology podcast episode has been sponsored by Forensic Psychology of Deception: A Criminal Psychology Guide To Deceit, Lying and Criminal Deception. Available from all major eBook retailers and you can order the paperback and hardback copies from Amazon, your local bookstore and local library, if you request it. Also available as an AI-narrated audiobook from selected audiobook platforms and library systems. For example, Kobo, Spotify, Barnes and Noble, Google Play, Overdrive, Baker and Taylor and Bibliotheca.

Introduction To The Forensic Psychology Of Deception (Extract from Forensic Psychology of Lie Detection COPYRIGHT 2025 CONNOR WHITELEY)

To kick off this fascinating book, we need to understand what actually deception is, why psychologists are interested in the area and what are some of the theories around lie detection that the literature is built on, at least in the early days.

Ekman’s Theory of Lying

As a result, our first theory that is critical in the development of lie detection as a field of study comes from Ekman and his theory of lying. Since the modern study of lie detection can be traced back to Paul Ekman’s book Emotions Revealed and whilst it is largely outdated by modern standards, especially in 2024. The book was very useful in generating ideas, interest and studies as different researchers wanted to explore the ideas written in this book.

In addition, Ekman believed that because of his academic work published in 1992 and 1996, that lies have to involve a person intending to mislead a victim and a victim that is unaware of that intention. For example, if a friend asked me to post an anniversary card at 7 am in the morning because I was going to work but I didn’t post it until 4 pm that day but I said that I had posted it at 7 am because I didn’t want them to know the truth then that is a lie. I misled my friend and they didn’t know I was misleading them.

An oddly specific example I know but I might have lied because I didn’t want them getting distressed that it wasn’t done exactly as they instructed.

Anyway, Ekman’s ideas follow the concept that not all forms of deception or misleading information can be considered a lie. At first, I didn’t really understand this idea because surely every type of deception involves a lie to someone or you convincing someone of something that isn’t true. Yet when we think about it, there are types of deception that don’t involve lies. For instance, magicians are very open about their deception, as well as a secret isn’t lying if other people know that it’s a secret. A final example is that false memories of sexual abuse aren’t technically lies according to Ekman, because the intention isn’t to mislead.

Therefore, current academic research focuses on developing a set of interviews and procedures that make it more difficult for people to hide cues of their lying from police officers and other people. This is a large focus of the book and we get to cover some of my favourite interview sets that are absolutely fascinating and I’m excited to share them with you.

Why Is Lie Detection Difficult?

In addition, Ekman laid out some basics about lying that we need to take a moment to appreciate because they help people to understand why lie detection is so difficult and it isn’t as easy as laypeople imagine.

One of the first problems that make lie detection hard is that more often than not, we don’t have baseline measurements for the interviewee for their “manipulation”. For instance, we don’t actually know how their touch, stroking and other small ways how a person manipulates their body is normal for them. One person might naturally blink a lot and someone else might blink rarely because that is normal for them. The problem with this is that it makes lie detection very difficult because when someone lies they typically have lying cues but if we don’t know how these cues cause changes to a person’s body, we cannot be sure if a body manipulation is a cue or something that is normal to that person.

This first problem is made even more difficult when we consider that body manipulations are related to strong emotions, not always if someone is lying as well as you cannot make lie detection judgements on emotions alone because they are often misleading signs of deception.

Secondly, the lying contexts can make lie detection difficult because lying contexts vary wildly. For example, it is easier to tell a lie if you have time to prepare for it compared to when you have to lie on the spot.

Personally, I was very, very good at telling lies about certain topics as a child because I had to to survive, so in certain contexts around my sexuality, I was an expert liar. Yet if I stole something or if I had to lie about something that didn’t directly impact on my survival chances then I was a worse liar, so context can be everything in lying.

We explore this in a lot more depth later on.

Thirdly, assessing a person for lying is very complex because we need to monitor everything in a person from their facial features to changes in their voice. Therefore, one of the biggest mistakes that someone trying to detect lies can do is to only focus on the voice and facial aspects. These might be the easiest parts of a liar to focus on because these can be useful lying cues. Yet equally, these are the easiest cues for a liar to change, monitor and manipulate so it is critical that lie detectors focus on more cues too.

As a result, Ekman suggested in his 1992 paper that it is important to look out for “leakages” in the way how the liar’s strong emotions manifest themselves. His ideas included looking for faster breathing, an increase in sweating and swallowing amongst others. As well as Ekman suggested looking out for negative emotions like fear that might manifest as louder speech because that is associated with anger and speech pauses and errors. Also, if an interviewee has a whitening of the face then this suggests fear and a lack of a story’s preparation too.

“Leakages” and lying cues play a major part in this book.

Building upon this further, Ekman proposed that facial features are key to telling if someone is lying or not. Since if someone is actually happy then this real emotion involves facial movements as well as real sadness and fear requires forehead expression. Whereas anger, according to Ekman, is very difficult to fake based on his 1985 theory.

Furthermore, the muscles involved in anger are very hard to control so an innocent person might struggle to control their anger, but a liar might struggle to make their anger look real. Then being able to tell whether these muscles are being used could be a reliable and important indicator of lying behaviour.

Throughout the book, we’ll see how reliable these facial markers are for lie detection.

In terms of research support, Hatz and Bourgoeus (2010) tested these cues by getting college students to cheat on an experiment in a both real transgression scenario and a fake one that involved them being secretly filmed and confronted about their behaviour causing them to tell a lie, afterwards a panel of judges looked at their behaviour. The researchers demonstrated that the judges found that the truth-tellers were angry and used more angry words in the film compared to the liars.

How Good Are People At Lie Detection?

To wrap up this first chapter, we need to know a critical fact about people’s ability to detect lies because this forms a core part of the book. We need to understand that generally speaking people are little better than chance in their ability to detect lies, regardless of the fact that some people are better than others at detecting these forms of deception (Ekman et al., 1999).

We need to understand this fact because one of the main purposes of creating procedures and interview sets that maximise lying cues is so we can give interviewers the most chances to tell if someone is lying or not. People need these increased chances because people are naturally bad at telling if others are lying.

Also, Ekman believed that a person could be trained to better detect lies and I think there is some truth in that. As we explore this subfield in more detail in the other chapters, I think there are valid and somewhat reliable ways to improve lie detection abilities but you need very specific techniques that a lot of laypeople wouldn’t use or even know about unless they research the area in-depth.

Ultimately, the bottom line is that there is no single simple indicator that instantly reveals who’s lying.

Now that we understand some basics about lying behaviour, we need to explore whether so-called professional lie detectors are actually any better than laypeople?

This is going to be fun.

I really hope you enjoyed today’s clinical psychology podcast episode.

If you want to learn more, please check out:

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Forensic Psychology of Deception: A Criminal Psychology Guide To Deceit, Lying and Criminal Deception. Available from all major eBook retailers and you can order the paperback and hardback copies from Amazon, your local bookstore and local library, if you request it. Also available as an AI-narrated audiobook from selected audiobook platforms and library systems. For example, Kobo, Spotify, Barnes and Noble, Google Play, Overdrive, Baker and Taylor and Bibliotheca.

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Have a great day.

Forensic Psychology Reference and Further Reading

Whiteley, C. (2025) Forensic Psychology of Deception: A Criminal Psychology Guide To Deceit, Lying and Criminal Deception. CGD Publishing. England.

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