How to Spot a Liar: Kate White on the Techniques of Deception in Mysteries

At the heart of nearly every irresistible psychological thriller is a simple, deliciously dangerous idea: someone the protagonist knows—or has recently met—isn’t at all who they appear to be.

In these novels, trouble never bursts through the door wearing a ski mask. It strolls in smiling—capable, reassuring, perhaps downright charming. Sometimes it’s even the person brushing their teeth next to the protagonist in the morning. Then, either in one jolting moment or through a slow drip of unease, she realizes she’s missed something crucial. The danger didn’t arrive late. It was there all along.

What makes this premise so compelling is that it’s hardly confined to fiction. Real life is full of people who aren’t as advertised—and unlike in novels, uncovering that truth never ends up being delicious. The fallout doesn’t necessarily involve a body (at least let’s hope not), but it can still leave plenty of wreckage behind.

After researching and writing nineteen mysteries and thrillers (my latest is I Came Back for You, March 1, Thomas & Mercer), I’ve spent a lot of time talking to experts about deception. What I’ve learned has not only helped me sharpen my plots, but it’s also sometimes proved useful in my personal life.

Here are my favorite strategies for spotting a deceiver, even if he is brushing his teeth next to you in the morning (unfortunately, I speak from experience in that case!)

Don’t Bother Becoming a Body-Language Expert

When body language first became a popular topic, books and articles promised that liars routinely gave themselves away through specific expressions and gestures. A hand over the mouth. Eyes looking up to the right. Learn these so-called “tells,” the thinking went, and you could protect yourself from deception.

The problem is that this approach isn’t foolproof. “Tells aren’t universal,” explains psychologist Dale Atkins, author of eight books, most of which focus on self-development. “They vary from one person to the next.” Some people fidget, touch their face, or avoid eye contact simply out of habit or anxiety. And many commonly cited tells, she notes, are influenced by gender and culture, which makes them far less reliable than we tend to believe.

But Do Notice the Biggest Tell of All

While many so-called tells vary from person to person, there’s one type of behavior that consistently shows up with deception: inconsistency. “If someone offers an explanation and the details shift in the retelling—or if they later give you a suddenly expanded version—that should be a red flag for you,” says New York City psychiatrist Dr. Karen Rosenbaum.

Why can’t pretenders keep their facts straight? “When people lie, they’re also hearing themselves and deciding how the story sounds,” says Will Valenza, the retired chief of the Glens Falls NY police department. “They start worrying that you’re not buying it, so they gradually add details or even change certain details to make the story seem more credible. You see this a lot in news coverage of men who’ve murdered their wives and initially offer an explanation for why the women might be missing.”

Be Wary of Perfect Memories

A deceptive person will often rehearse a fake story in their mind, embellishing it with plenty of details in order to make it seem very real or to detract from the core lie they’re trying to bury. If you listen closely while they’re relating the story, you can notice that it sounds almost too precise.

I.S. Berry, author of the award-winning espionage novel The Peacock and the Sparrow, spent six years as a CIA counterterrorism officer. “When I spoke to someone, I always had to ask myself: could this information be trusted?” she says. “One of the things I came to see over time is that no one should know every detail. If someone rattled off multiple license plate numbers to me, I knew to be suspicious.”

Try a Very Pregnant Pause and See If It Leads to Squirming

BBC presenter and acclaimed media consultant Laura Trant has a deceptively simple trick for spotting liars: just go quiet and wait. “Silence can be very destabilizing for someone who’s lying,” she explains. “It makes them wonder if you’re buying what they’re saying—and then they start working harder to convince you.”

Dare to Be a Data Detective

If your instincts are on high alert, there’s nothing wrong with confirming details through public records, online research, or trusted contacts. Forensic psychiatrists, for example, assess a person’s mental state not just by talking to them, but by checking records and speaking with people in their orbit. As Dr. Rosenbaum puts it: “If someone is being truthful, they have nothing to fear from you doing a little factchecking.”

Most of All, Don’t Resist the Uh-uh Moment!

No matter how skilled you get at spotting deception, it won’t help if you ignore your instincts. “You have to pay attention to that gut feeling that says ‘uh-oh,’ something’s off,” says Dr. Atkins. Our minds love to rationalize inconsistencies—but one of the biggest mistakes you can make is dismissing that inner alarm.