The Psychology Behind Detecting Lies

By Anagha Dogiparthi




Picture of Brain (Parts of the Brain | Introduction to Psychology)


Imagine you are transported back to your childhood days when your biggest fear was being caught for stealing a chocolate bar from the cabinet without permission. You quietly snuck from your bedroom, innocently thinking your parents were asleep or occupied and crept up to the cabinet. Your mouth watered with the anticipation of biting into a large, milky bar of chocolate, and you reached up and grabbed one. Little did you know your parents were standing right behind you, prepared to dish out the adequate punishment- but first, they had to interrogate you. Depending on what kind of kid you are, you would either lie about your devious crime, or you would confess immediately, fearful of the consequences. If you were the kid who lied, it’s almost a guarantee that your parents understood your deceit at once- but the real question is how did they do it?


Detecting lies can be narrowed into several categories ranked in order of details. A situation like the one previously described doesn’t require much talent, as it’s very easy to tell when a child lies most of the time. On the other hand, revealing evidence of criminal acts needs a lot more skill and precision to extract the most useful details in an interview.


One useful method often used by interviewers of criminals is “increas[ing] cognitive load by, for example, asking [the criminals] to tell their stories in reverse order. Truth tellers can rely on their memories to tell their stories backwards, often adding more details, but liars tend to struggle.” Interviewers can then determine the honesty of their interviewees by detecting the level of details provided, and how much hesitation or grammatical errors they use. This may not seem like a very big deal on a low level, but if the severity of the crime is large enough, it can end up providing justice to many victims.


Another useful method is encouraging interviewees to say more than the story that they have already provided. Since honest people will typically withhold certain pieces of information to avoid a big punishment, they will reluctantly provide the details necessary. On the other hand, since liars will have a crafted story they do not diverge from, they will likely not have the bandwidth or creativity to provide more information on the spot. As Aldert Vrij, a professor of applied social psychology at the University of Portsmouth says, “It’s particularly useful to ask unexpected questions in the interviews. Because liars often prepare their stories, surprise questions can leave them floundering for a response or contradicting themselves.”.



Police Interview (https://www.istockphoto.com/illustrations/police-interview)


There are also many well-trained computer programs that can detect lies based on the data provided, regarding common psychological behaviors. One of these computer programs is the one created at the University of Texas at Austin, which can “analyze written content and can, with some accuracy, predict whether someone is lying.”To program this device, three main “markers” seemed to stick out as major clues that someone was lying: fewer first-person pronouns, more negative emotion words, and fewer exclusionary words.



Psychology Software Tools (https://pstnet.com/)


The reasoning behind fewer first-person pronouns is that liars, not being fully confident in the stories they’re telling, refuse to acknowledge ownership of what they are talking about. As for more negative emotion words, such as “hate,” they are often used to express guilt and anxiousness indirectly. Being as nervous as they are, and sometimes feeling bad for what they have done, they have no choice but to express their emotions through words typically detonated as “strong” in a negative fashion. The last one, fewer exclusionary words, is a little bit more complicated. Exclusionary words are essentially words that separate two different things- this may include “but,” “nor,” or “except.” Since liars often want to leave their stories vague enough that they won’t get caught with evidence, they will refrain from using these words to help convince those around them of their innocence.


Do you recognize yourself doing these things when you lie? Well, it’s very common, though obviously on a smaller scale, to involuntarily express certain behaviors when doing something a lot of people do. For example, even telling the truth has its own separate behavioral clues.


These common psychological behaviors of liars, or even criminals, ought to give you a nice heads up the next time someone lies to you about something. In the future, if you’re in a situation like that, feel free to refer to this article!


References

Zimmerman, L. (2016, March). Deception detection. Monitor on Psychology.

https://www.apa.org/monitor/2016/03/deception.

Vrij, A., & Granhag, P. A. (2014, September 18). Eliciting Information and Detecting Lies in Intelligence

Interviewing: An Overview Of Recent Research. Wiley Online Library.

http://onlinelibrary.wiley.com/doi/10.1002/acp.3071/abstract.

Adelson, R. (2004). Psychological sleuths--Detecting deception. Monitor on Psychology.

https://www.apa.org/monitor/julaug04/detecting.