Be honest for a second: we all tell lies from time to time, whether it's fibbing about the reason we’re late or telling a loved one they look fab in that expensive new outfit when actually we think the opposite.
Research from the 1990s found that for most of us, this amounts to about one or two lies per day on average. These lies are usually quite harmless, though, and most of the time we do our best to tell the truth.
In contrast, there are some people who take lying to an entirely different level. For a study published in 2021, a team of US researchers asked hundreds of students to keep track of their lies for 91 consecutive days – of the 116,366 lies told, a disproportionate number flowed from the lips of a minority of prolific liars.
Another study found that five per cent of people are responsible for half of all lies told. These are the people who lie again and again, and whose lies are sometimes absolutely enormous.
Some prolific liars are able to use their deceit to their advantage, at least for a while. If and when they’re found out for the enormous whoppers they’ve told, they can end up becoming notorious because of it.
Think of Elizabeth Holmes (convicted in 2022 for defrauding millions out of investors after lying to them about the health technology her company, Theranos, was developing) or Lance Armstrong (the disgraced cyclist stripped of his seven Tour de France victories, who confessed to using performance-enhancing drugs after years of denials).
Other prolific liars might not draw such attention to themselves, yet they stand out for their willingness and ability to deceive on a regular basis – you might even know one in your own life.
There are two main parts to the story of why a minority of people are willing and able to lie so often. One aspect has to do with having the mental capabilities to deceive. The other aspect has to do with morality and having the kind of personality traits that make it easier to cope with, and justify, being chronically dishonest.
Fluid Intelligence
“Telling a convincing lie requires cognitive effort,” says Molly MacMillan, a researcher at the Memorial University of Newfoundland, Canada, who has written about the mental demands of lying.
Honesty is relatively low effort, she explains. Lying, by contrast, involves suppressing the truth, inventing a fabrication and then keeping track of it. Brain scan studies have shown all this mental activity leads to greater neural activation in areas responsible for cognitive control, as compared with telling the truth.
It’s for this reason that lying is much harder if you’re burdened with another mental task at the same time. “Studies have found that people are more likely to be honest when speaking in a second language, when tired or when occupied with another task or activity,” says MacMillan.
Indeed, one approach to conducting lie detection is premised on the idea of increasing ‘cognitive load’ – for example, asking a criminal suspect to tell their story backwards, so that it’s harder for them to maintain a lie.
The mental challenges involved in lying provide the first clues as to what is different about prolific liars – especially those able to get away with their lies. They need the mental aptitude to cope.
Consistent with this, a study published in 2023 tested the lying ability of 400 participants and found that those more skilled at lying in a spontaneous conversation tended to score more highly on ‘fluid intelligence’.
This captures a person’s ability to reason and problem-solve under pressure (in contrast to ‘crystallised intelligence’, which is more about being knowledgeable).
Other relevant research has looked at the link between counterfactual thinking and lying. Counterfactual thinking is when you wonder about how things could have gone differently (pondering “What if...?” or “If only...?”).
Some people are more inclined to it than others and although it's not the same as deliberate deception, both involve inventing other realities. In one study, researchers gauged participants' tendency for counterfactual thinking by asking them to write a diary entry about an incident and seeing how often they included this kind of reasoning, such as: If only I had done x, then y wouldn’t have happened.
The study showed that counterfactual thinkers were also more likely to lie to protect their reputation in a pair of hypothetical scenarios: to conceal why they didn’t attend a party or to cover their involvement in a traffic accident.
This again shows how people’s proclivity for lying is at least in part associated with having the mental skills or habits required for deception.
This cognitive part of the story is also supported by a body of research that’s looked into lying among children.
Among these findings, there’s evidence that young children with more inhibitory control (for example, they were better able to follow the paradoxical instruction to say ‘night’ or ‘Moon’ in response to a picture of the Sun or say ‘day’ or ‘Sun’ in response to a picture of the Moon) were also more likely to lie in another part of the study.
This makes sense given that lying involves inhibiting the truth.
Other studies with children are in a similar vein, for example, showing that kids aged six and seven who showed superior lying skills also scored higher on a test of verbal working memory (the ability to hold more words in memory over a short period of time).
Again, this is a vital skill for keeping track of an ongoing deception.
Given the mental demands of lying, it also makes sense that practice seems to make perfect. In 2012, an international group of researchers instructed some of their participants to tell more lies during an initial phase of the study.
After this training, lying became less cognitively demanding for these people, as if they’d got into the habit of suppressing the truth. This could help explain how prolific liars are able to keep up their deceptive behaviour: through sheer repetition of the behaviour, the act of lying likely becomes easier.
Lying personalities
The ability to lie is only part of the story. Of course, most intelligent and quick-witted people don’t go around spreading lies just because they can. From a young age, most children are taught that lying is morally wrong and, through life, many of us also learn that lying can backfire spectacularly despite the short-term advantages it may bring.
However, there are people with certain personality traits, especially high scorers in the so-called ‘dark triad’ traits of Machiavellianism (characterised by manipulation and lack of empathy), narcissism and psychopathy. These people seem to be much more comfortable with lying to get ahead or boost their reputations.
People who score highly on Machiavellianism are especially manipulative; high scorers on narcissism are ego-centric and grandiose; while high scorers on psychopathy tend to be callous and lack empathy.
It follows that people with these traits would not be concerned about using lies to their advantage and many studies have shown the willingness of people with these traits to lie more often – and, what’s more, to feel good about doing it too.
When it comes to deceptive skill, a 2011 study suggested a mix of psychopathic traits and high emotional intelligence (including the ability to control your emotional expressions) might be especially conducive, allowing someone to avoid revealing their true feelings while faking other feelings in a convincing manner.
A related reason that the people with the dark triad traits are willing to lie with such abandon is that they believe most other people are at it.
As Prof David Markowitz at the University of Oregon in the US and his colleagues put it, “Those who lie prolifically might feel justified in their deceptive behaviour because they believe that others are also lying at high rates.”
Some researchers, such as the psychologist Dr Christian Blötner at FernUniversität in Hagen, Germany, have focused on the trait of Machiavellianism in particular.
They observed how people with Machiavellianism use and understand less obvious deception: when inaccurate or meaningless information is used to gain advantage or avoid disadvantage (a type of lying the study refers to as ‘bulls**t’).
This is probably relevant to the kind of lies we're often subjected to during election time and during other contexts where people are engaged in flagrant self-promotion.
Blötner defines bulls**tting as “information expressed with indifference for truth, meaning or accuracy, which is supposed to impress, persuade or mislead others for individual advantages.”
His research suggests that people who score highly in the avoidance facet (the negative motivational tendency) of Machiavellianism are more inclined to bulls**t in an evasive way, such as avoiding a journalist’s questions.
Meanwhile, those who score highly in the approach facet (the positive motivational tendency) of Machiavellianism are more inclined to engage in so-called ‘persuasive bulls**tting’, such as by exaggerating their achievements.
What makes a good lie?
In 2019, a team led by Brianna Verigin at Maastricht University, Netherlands, surveyed nearly 200 people about their lying abilities and asked them what strategies they use to lie effectively. The results were not rocket science, but nonetheless, provide a hint as to how many prolific liars get away with their lies for so long.
The most commonly cited strategy was to keep lies clear and simple. This is a shrewd approach given what’s known about the cognitive demands of lying. The more straightforward a lie, the easier it’ll be to keep the details consistent and avoid getting caught out.
The next most commonly cited strategies were to keep lies plausible and avoid giving specific details. Lastly came embedding the lie within a truthful story.
For an idea of how this last strategy might work in real life, imagine a criminal suspect being asked where they were at the time of a robbery.
Instead of concocting a fictional alibi from scratch, the skilful liar might instead use their memory of a specific real episode from their life at a similar time of the day and week. That way, they could provide details as needed from the real memory, rather than having to invent fictitious information on the spot.
Pathological liars
Among the prolific liars, there’s also a smaller group of so-called ‘pathological liars’ with a condition sometimes known as pseudologia fantastica or ‘mythomania’.
These individuals tend not to lie with such strategic purpose and, in fact, their lives are usually made a misery by their compulsion to lie. Unlike many prolific liars, they might experience remorse, but from a young age, they just can’t stop themselves from lying again and again.
“Pathological liars tell lies with a greater frequency than most others and the lies told tend to cause [them] impairment in functioning, elicit distress and are more likely to pose a risk of danger to self or others,” says Dr Drew Curtis, the author of Pathological Lying: Theory, Research, and Practice.
Another key contrast with most prolific liars is that pathological liars might actually lack cognitive control. Whereas an effective prolific liar uses their mental prowess to suppress the truth and maintain a lie, the pathological liar simply can’t stop themselves spreading fictions compulsively, even as the costs mount up.
“It’s not clear that pathological liars have no moral compass,” explains Curtis. “Rather, executive functioning deficits may be related to pathological liars not being able to predict the future – the consequences of getting caught – when engaging in lie-telling.”
Lying ability is not the same thing as willingness to lie, but the two things are inevitably related. Understanding what makes prolific liars – as opposed to pathological liars – tick requires taking both these parts of the story into account.
Prolific liars think their deception is justified; they care more about getting ahead than being morally good. And, if they’re to keep their lying up for any length of time without getting found out, they need certain cognitive abilities to cope with the mental challenges involved.
These characters see lying as a useful tool, but the truth is, it’ll probably backfire.
As well as the high-profile downfalls of Lance Armstrong, Elizabeth Holmes and others, there’s also research showing that frequent liars experience a poorer quality of life and lower self-esteem. Another pertinent study found that lies told to a close partner were more likely to be found out.
So be warned, your parents were right: honesty is the best policy.
Our experts
Molly MacMillan, is a researcher at the Memorial University of Newfoundland, Canada. After graduating from Mount Allison University with a BSc in biology, she went on to Memorial to complete a Masters degree in cognitive psychology and her PhD.
Dr Christian Blötner has been at the FernUniversität in Hagen, Germany since May 2022, starting as a Research Assistant before becoming a Temporary Academic Councillor.
Beforehand, he worked multiple research internships at Westfälische Wilhelms-University Münster before becoming a tutor. Then, he went on to become a lecturer for the psychology courses at the Technical University of Dortmund.
Dr Drew Curtis is a director of a PsyD and MS counselling at Angelo State University as well as a published author. Along with 'Pathological Lying: Theory, Research, and Practice', he's done, he's also co-authored with Chris Hart the book 'How You Can Avoid Being Duped'.
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