The Science of Being Completely Full of Sh*t

What Is a Pathological Liar?

“Pathological liar” is one of those expressions that’s thrown around without necessarily thinking about what it means — are some people literally incapable of telling the truth?

There is no properly agreed-upon definition of pathological lying. But not only does it have a proper name — Pseudologia fantastica — it’s also cited in the diagnostics of other conditions (like Munchausen syndrome), creating quite a complicated situation.

In 1915, husband and wife criminology team William and Mary Healy offered up one potential definition, which is still used by some parties today, defining it as “falsification entirely disproportionate to any discernible end in view, may be extensive and very complicated, manifesting over a period of years or even a lifetime, in the absence of definite insanity, feeblemindedness or epilepsy.”

So there’s a difference between bullshitting to get what you want and being a pathological liar — there needs to be at least some semblance of, for want of a better word, pointlessness to it to count. Claiming you graduated from Princeton in order to get a job is lying; spending many years claiming to have invented the question mark is pathological.

And confusingly, even pathological liars find telling the truth more rewarding than not. It’s all really complex.

How Common Is It?

But how many of these deluders are there? A 2010 study published in Human Communication Research found almost half of all lies were told by just 5 percent of people. A 2021 study published in Communication Monographs looked at 116,366 lies told by 632 participants over 91 consecutive days. Seventy-five percent of them told between zero and two lies per day, and 89 percent of the lies reported were classified as “little white lies” — i.e., harmless ones along the lines of pretending to like a crappy gift. The biggest bullshitters in the study, the most full-of-nonsense 1 percent, averaged 17 lies per day.

“People are mostly honest, except for a few pathological liars,” said study co-author Timothy Levine, of the University of Alabama at Birmingham. “There are these few prolific liars out there, and I think this study showed that they are a real thing. There is that kind of top 1 percent who are telling more than 15 lies per day, day-in, day-out.” 

Something worth bearing in mind is that the lies were self-reported, meaning participants could easily leave out anything they thought was either so small it wasn’t worth mentioning or so, uh, bastardy that they’d rather not share it. It’s also hard to imagine recording your 15th lie of the day without feeling like kind of a baddie, something likely to have affected results.

Self-reporting lies also brings up the issue of lying without realizing you’re doing so, something that other studies suggest we do a lot. In 2002, a study by Professor Robert S. Feldman — a high-profile figure in the world of lying studies — played conversations people had had back to them, asking them to look for lies and found they told far more than they thought they had. In a 10-minute conversation, 60 percent of people lied at least once. (While men and women have generally been found to lie just as much as one another, women tend to tell lies intended to make the person they are talking to feel better, while men opt for lies that make themselves look good.)

Can Lying Be a Good Thing?

While 17 lies a day can sound like a lot, depending on an individual’s lifestyle, it might not be. If you have a client-facing job and tell everyone you meet with that it’s good to see them, and it actually isn’t, that’s a lot of lies. Again, it all gets very complicated — being nice, or likable, or kind, or charismatic (four different things) might all involve a lot of little white lies. If someone asks how their new haircut looks, and it looks really shitty, what’s the right thing to say?

As Professor Kang Lee of the University of Toronto points out, we are taught from a very young age that being polite often involves lying. 

A modelling study done in Finland in 2015 found that there was something of a curve when it comes to honesty and building community relationships — while excessive lying is destructive, so is excessive honesty. In other words, a certain amount of “pro-social” lying makes everything run more smoothly. Ethicists have put enormous amounts of work into trying to work out where little white lies sit on the good/bad continuum, to basically no consensus at all.

However, Feldman argues that we should strive for more openness and honesty, even when it isn’t the perfect solution for every occasion, saying, “By asking others to tell us the truth ... you're going to have a better understanding of who you are and you’re going to end up leading a more authentic life.”

Meanwhile, neuroscientists at University College London found that the more small lies you tell, the more likely you are to tell bigger ones, as your amygdala (a part of the brain that gets very active when lying) becomes desensitized — tell people their shirt looks nice enough times, and before you know it, you’re in the “No, really, I am a war hero” area of bullshit.

What Makes Someone More Likely to Be a Pathological Liar?

In 2005, researchers at the University of Southern California found the first evidence of brain abnormalities in pathological liars — the prefrontal cortex is always very active when people are telling lies, but their study found that liars had 25 percent more white matter, and 14 percent less gray matter, in their prefrontal cortex than non-liars, suggesting there can be a physiological predisposition to being a bullshit artist.

In children at least, it can be linked with intelligence. The head of a 2025 study that found kids with better working memories make better liars said, “Parents may sometimes become frustrated when their child lies about sticking their hand in a cookie jar, but we can take heart that the more believable the explanation for the crumbs around their mouth, the more intelligent they are.” Along those lines, teenage liars are more popular than teenage truth-tellers. 

There are demographic trends, too. A 2014 study of 2,980 British people published in the Journal of Language and Social Psychology found that the biggest liars tended to be men in young adulthood in high-status occupations — pretty much exactly who you’d think, smooth-talking bastards in nice suits spinning webs of bullshit and thriving as a result. (That paper also reveals that the body of research done in this area is referred to as “the deception literature,” which just sounds cool. If that was the title of an eight-part Netflix show about a pair of psychologists diving into a dark world of conspiracy and intrigue, enjoying a cute will-they-won’t-they dynamic all the way through, someone would make many millions of dollars.)

And, just to complicate everything further, there are behavioral/nurturing factors that can make someone more prone to lying. A 2020 study published in the Journal of Experimental Child Psychology found that children who were told lies by their parents (along the lines of “If you don’t tidy your room I’ll call the police”) told more lies as adults. 

I’ll say it one last time: It’s enormously complex, as potentially all these things can feed into one another — could a physiological predisposition toward lying then lead to something verging on a brain-rewiring addiction? God damn it, it’s fucking insanely complicated.

Or maybe it isn’t, because maybe none of this is true. It could all be lies, lies, damned lies! Bullshit, bullshit everywhere, forever and ever and ever. God damn. God damn.