How's your poker face? Why it's so hard to sniff out a liar

May 19, 2014 by Ricky Van Der Zwan And Anna Brooks, The Conversation
Interesting hand … could you keep it a secret? Credit: Carsten Tolkmit/Flickr, CC BY-NC-SA

As the annual World Series of Poker gets rolling in Las Vegas later this month, hopeful competitors will be buying in and getting their poker faces on.

But why is it such a challenge to recognise deception – both on and off the poker table – even with past experience to draw on and lots of cues seemingly available?

Most of us are proficient liars. We all lie, probably every day, about something or other. Ever answered the standard question of "how are you?" with a less-than-forthright reply?

We understand the concept of lying before we turn four: Charles Darwin reported his son, a few months shy of his third birthday, trying to lie and there are data suggesting the behaviour can manifest from as young as two years.

And just as everyone engages in deceptions, everyone wants to know how to tell if someone else is lying. It seems as though it should be easy – there are "tells": sweating, eye movements, micro-expressions, changes in body posture and even changes in speech patterns, that can help us recognise a lie.

Those signals are a type of natural polygraph. Like mechanical lie-detector tests, they rely on a set of physiological changes that occur when we lie. Telling a porky pie, even a so-called white lie, requires cognitive and emotional effort.

Lying activates our autonomic nervous system, and the more venal the lie – the more there is at stake – the more activated the becomes.

Why is it so hard to detect a lie?

Pants on fire (if only it was that easy)

The answers are surprising.

First, there is "noise" in the lie-detection system: there are many things that activate the human autonomic nervous system.

Nervousness is a good example. People typically get nervous when

  • they are being interrogated, about anything
  • they meet for the first time someone to whom they are attracted (which, by the way, is one of the circumstances under which we are very likely to lie about something)
  • the stakes are high – when much depends on what they do, or how well they do it
  • there's confrontation involved: a deadline, great expectations … even in-laws.

When we are nervous we sweat more. We sweat a different type of sweat and so we smell different. We fidget and our hair stands on end. We either don't make any or make exaggerated eye contact. We change the way we speak and, without knowing it, the pitch of our voice changes.

Those changes also occur when we are lying. So it is a myth that there exists a reliable, unique set of cues that signal someone is lying. Some behavioural cues certainly are correlated with lying, but most of those also are correlated with other behaviours too.

Second, there is the cost to the lie-detector of a "false alarm". Socially speaking, it's a high-stakes game: the fear of the damage and embarrassment wrought by mistakenly calling someone out on a lie, combined with the high burden of proof involved, stack the decks against successful "prosecution".

Perhaps most surprisingly though, we are generally less interested than we think in actually discerning the truth. We are, very often, willing to accept as truth lies that smooth social interactions.

Similarly, lies that are congruent with our world-views or, and especially, with our self-image will less often be "called out". In other words, we actually are very skilled at not recognising lies.

I lie, therefore I think

Of course, the little white lies we tell to keep conversations flowing or to compliment (or at least avoid offending!) our friend/partner/boss seem hardly interesting. Juicier are the venal deceits that, when detected, leave trust shattered and lives changed. As it turns out, all lies, big or small, are tactical deceptions.

Tactical deceptions require the liar to actively manipulate information to mislead another. They are interesting because the creation of such a deception has been interpreted as evidence that the liar has developed a theory of mind – I lie, therefore I think.

If that is true the implications are broad: both old world and new world monkeys have been observed in tactical deceptions. The same is true for other great apes, and even ravens.

Lies, damned lies, and experts

Mark Twain, lamenting his lack of skill with numbers, stratified statistics as a worse than average form of lying.

Nonetheless – and acknowledging there is no small opportunity for irony when a researcher asks about how often people lie – who lies and how often are open questions across the behavioural sciences.

We do know almost everyone lies. Women and men lie on average equally often, but about different things. There is some evidence too that men are better liars than women.

Perhaps unsurprisingly, estimates of how often we lie vary wildly. That is partly because context is important. Lying is, after all, a type of social glue, and – not surprisingly – people in surveys.

So the next time you pull up a chair at the casino or with mates at a poker night, remember – while you may find it hard to tell if your opponents are lying, they're probably also finding you hard to read.

Explore further: True story: Not everyone lies frequently

Related Stories

True story: Not everyone lies frequently

December 13, 2013
Does everybody lie? We are taught that this is common sense and that most people tell little white lies. But perhaps this isn't true. A recent paper published in Human Communication Research found that many people are honest ...

Deception can be perfected

December 6, 2012
With a little practice, one could learn to tell a lie that may be indistinguishable from the truth.

Liars find it more rewarding to tell truth than fib when deceiving others

January 23, 2014
A University of Toronto report based on two neural imaging studies that monitored brain activity has found individuals are more satisfied to get a reward from telling the truth rather than getting the same reward through ...

The unconscious mind can detect a liar—even when the conscious mind fails

March 24, 2014
When it comes to detecting deceit, your automatic associations may be more accurate than conscious thought in pegging truth-tellers and liars, according to research published in Psychological Science, a journal of the Association ...

Recommended for you

Short-course treatment for combat-related PTSD offers expedited path to recovery

January 23, 2018
Symptoms of Post-Traumatic Stress Disorder (PTSD) can be debilitating and standard treatment can take months, often leaving those affected unable to work or care for their families. But, a new study demonstrated that many ...

Priming can negate stressful aspects of negative sporting environments, study finds

January 23, 2018
The scene is ubiquitous in sports: A coach yells at players, creating an environment where winning is the sole focus and mistakes are punished. New research from the University of Kansas shows that when participants find ...

Social and emotional skills linked to better student learning

January 23, 2018
Students with well-developed and adaptive social and emotional behaviours are most likely to excel in school, according to UNSW researchers in educational psychology.

Study of learning and memory problems in OCD helps young people unlock potential at school

January 22, 2018
Adolescents with obsessive-compulsive disorder (OCD) have widespread learning and memory problems, according to research published today. The findings have already been used to assist adolescents with OCD obtain the help ...

People with prosthetic arms less affected by common illusion

January 22, 2018
People with prosthetic arms or hands do not experience the "size-weight illusion" as strongly as other people, new research shows.

Intensive behavior therapy no better than conventional support in treating teenagers with antisocial behavior

January 19, 2018
Research led by UCL has found that intensive and costly multisystemic therapy is no better than conventional therapy in treating teenagers with moderate to severe antisocial behaviour.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.