The trouble is that the things we typically rely on to help us read people—facial expressions, body language, word choice—can always show a degree of variability. The assumption is that lying people will all present themselves in the same predictable way, when it’s clear that individual differences are so broad as to make these observational tips and tricks close to useless. While the techniques we’ve discussed in previous chapters can tell us plenty about the personality of a sincere person who is not actively trying to hide anything, it’s another story when it comes to deception.

An even bigger problem is that liars have access to all the same information as would-be lie detectors. If someone knows that touching their face often will be perceived with suspicion, they can simply take care not to do it. In fact, if you are dealing with a person who is very accustomed to lying, or in some way almost believes the story they’re telling you, they may show no signs at all.

So, why bother learning to detect lies if it’s something that’s so difficult to get right? Because there are certain conditions under which lie-detection accuracy can improve. If we can understand these conditions and have realistic expectations of our accuracy, we actually become better readers of character and more likely to avoid being deceived.

Lie detecting is generally most accurate when:

• You have a solid baseline of behavior against which to compare current behavior

• The person doing the lying is spontaneous, i.e., they haven’t had any time to rehearse their lie or prepare themselves

• The lie comes with real consequences for getting caught—this may up the stakes and make liars more nervous

Unfortunately, there is no single cue or sign that is a reliable indicator of someone’s dishonesty. One person may suddenly get more talkative, another may have a little tic they never do otherwise, another may get very serious and distracted. Besides, even if you could reliably spot nervousness, you cannot definitively link it to a lie—the person may just be nervous because they know you distrust them!

We could turn things around and look at it from the other angle—instead of asking how we can become better at spotting deception, can we understand why we get deceived in the first place? From this point of view, nothing much can be done about the existence of liars, but we can certainly look to ourselves and ask what aspects of our own personalities, beliefs or behaviors are allowing detection to go unnoticed.

For most people, lying is understood as an absolute moral wrong. We don’t like to lie, but we also hate to think that we’ve been fooled by a liar. If we have an unconscious belief that nobody would really lie to us, or that we could detect it if they did, we are preserving our ego somewhat, and assuring ourselves that the world is largely a just place.

Most people are good and honest, and they simply don’t like sitting in judgment of another, preferring the comfort of extending trust—how many of us falsely believe that others will behave with all the same moral scruples as we would?

If we can own our own bias, our expectations and our own unconscious beliefs about what others tell us, we have a better chance at detecting deception. It’s nice to imagine that you’ve got a good radar for liars, and are a gifted “human polygraph machine,” but nothing can get in the way of proper observation and analysis as much as the comforting belief that you’ve done it already. The methods we used in earlier chapters to discover a person’s values and personality will need an upgrade if we hope to use them to spot a lie.

It’s All About the Conversation

Ask the man in the street how to spot a liar and he may tell you things like, “his eyes go shifty” or “he looks up and to the right” or, “he stutters.” Even properly trained professionals may trust some of these techniques as foolproof ways to spot lying. But sadly, if it was this easy, lying would be much less commonplace and nobody would ever be deceived. The truth is, good lie detection goes a lot further than spotting isolated behaviors.

Of course body language matters. But in a way, a lie is a verbal construction—it’s a narrative that’s presented dynamically, in real time, and always in the context of another person listening in active conversation. Spotting lies is more than just watching like a hawk for a facial twitch here or a sweaty palm there. It’s about working with the entire conversation.

In conversation, you are participating, too. You can ask questions, steer the discussion, and subtly put pressure on the person so that they offer you information, rather than you having to seek it out. Let’s reframe lie-detection as a conversational skill rather than a set of single, static observations.

Your spouse is acting suspicious and you’re asking them about where they’ve been for the last five hours. Your child is telling you a story about how they got their black eye. Or a colleague at work is explaining to you at length why they’ve decided to drop your project. All of these are living, dynamic conversations, and not simply one-sided performances given on a witness stand.

Your ability to detect a lie will come down to the way you engage with the person telling the lie. Your interaction needs to be strategic and proactive. The first thing to keep in mind is to use open ended questions to start off with. Let the other person speak first, and often, to give them time to lay out any possibly conflicting facts or threads you can unravel later to prove a lie.

The appropriately named Dr. Ray Bull of the university of Derby is a criminal investigation professor who has been studying the art and science of this conversational technique for years, publishing papers in multiple psychology, behavior and law journals. His main finding is that it’s the relationship between the interviewer and interviewee, and the process of lie detection, that matters more than anything.

You want to keep your input to a minimum, at least at first. If you have any evidence or information of your own, keep quiet about it for as long as possible. Remember, the liar is in a difficult position. They have to convince you of a story yet they don’t usually know what you know. Withholding this information is often enough to get someone to accidentally blurt out something that resolves the issue for you completely.

For a simple example, if your spouse is telling you some long-winded story about how they spent the evening with a friend, ask them a few questions about what they did together, what they ate, what the weather was like at the friend’s place, and so on. Watch what they say. At the end of the conversation, you might reveal that you happen to know that that friend is on vacation at the moment, but by not revealing you know this, you give the liar the chance to recite their planned story, and reveal the flaw in their own story.

Watch for how the information is presented in general. Liars will usually offer a complete and highly detailed account all at once, but have little to offer beyond that when questioned. After all, they’ve rehearsed it all in their heads already, but haven’t rehearsed answers to questions they haven’t thought of. People telling the truth, however, tend not to come out with everything all at once, but will easily answer when questioned further.

You could try this out directly—suddenly ask a random and unrelated question that the person will definitely not have thought about beforehand. Then notice whether they are floundering to make up something on the spot. Liars also generally take longer to respond to questions and pause more often while narrating their response. Truth-tellers may struggle to remember a detail, but they’ll be far more comfortable saying “I don’t know” whereas a liar can often be seen to be rushing to make up some detailed nonsense to fill their perceived gap in knowledge.

If you do notice a discrepancy or even a flat out lie, don’t let on that you do. Wait a little and watch. You may get to see the liar actively spinning a tale before your eyes. When you eventually do confront such a person with evidence of deceit, continue to watch their response. People caught out in lying may get angry or shut down, whereas a person who is telling the truth may merely act a little confused, and will simply keep repeating the same story.

Dr. James Drikell is the head of the Florida Maxima Corporation, which researches behavioral science issues like deception detection. He has some extra clues on how to analyze the stories of multiple people who may or may not be collaborating on a deception. He claims that when two people are in on a lie together, they don’t consult with one another in telling their story, and don’t elaborate on the other’s telling, whereas truth tellers do. If you suspect two people of lying, watch how they interact with one another—honest people will be far more comfortable and proactive about sharing the story telling.

Use the Element of Surprise

Put yourself in a liar’s shoes (or remember the last time you told a whopper!). You have a lot of little details to keep track of, and have to appear calm and confident while doing so. You can imagine that’s it’s far easier to get your story straight if you’ve had time to run through everything in detail first. In other words, the more time you have to prepare, the more you can calm your nerves and rehearse your response.

Spontaneous liars are worse liars. If you can arrange it so that you question/talk to the other person on the spur of the moment, you might have a better chance at catching them out in awkward and rushed lying. As with the conversation techniques above, you are not really trying to guess whether the story you are presented with is true or false based solely on body language etc. Rather, you are trying to get the other person to reveal themselves, and to trip up in their own web of deceit.

We’ve already seen that surprise questions can catch a person off guard, since they take a liar away from their rehearsed script. Watch for any sudden changes in confidence, speed of speech, or eye contact. A classic giveaway is if a person responds to a direct and simple yes/no question with an evasive answer.

This may signal them trying to buy time to think of a convincing lie. A truth teller would have no trouble responding immediately and directly. Repeating the question or offering a long-winded, overly-detailed response is another way to buy time.

For example:

“Hey, someone ate my lunch from the fridge! Mike, did you eat my stuff?”

“Uh, what stuff is that?”

“You know, my lunch. I had it right here. I even had a Post-It note on it . . .”

“Yeah, well, people in this office can be sneaky . . .”

“You ate it, didn’t you?”

“Your lunch? Are you calling me a liar?”

“Well, did you?”

“Man, this is rich. I can’t believe you’d actually suggest . . .”

And so on!

Again, it’s all in the way the story is presented. When you catch someone off guard, they will be a little flustered all of a sudden, or may even respond with anger. Watch for a sudden shift in mood or speech. Someone might hide their panic by appearing to get angry (“why ask me such a stupid question?” or “What? You don’t know?”).

If you suspect someone of lying and want to get to the bottom of it, be casual and offhanded, and ask them questions quickly and before they’ve had time to spin a tale. If you can do this, a lot of behavioral or body language observations might suddenly be more useful—watch for nervousness, or attempts to hide, both physically and verbally.

Some people may suddenly act a little offended, or incur God’s protection (“I swear to God!”) instead of answering the question directly and plainly. What you want to do is catch a person in a moment of unguardedness and watch their reaction to questions. Very occasionally, a person may be so flustered and embarrassed they immediately confess in a panic.

How to Increase Cognitive Load

Telling the truth is pretty easy—all you have to do is remember what you can and say it out loud. Telling a lie is far harder, cognitively speaking at least. You’re not remembering anything, you’re actively fabricating a new story—one that has to have sufficient credibility. A great way to get liars to give themselves up is to tax their already overloaded brains until they make a mistake and tell you more obviously what you want to know.

The best approach is not to behave as if you’re in a formal interrogation situation, with you playing the role of no-nonsense detective. Rather, be casual but keep the person talking. Listen closely and apply gentle pressure to parts of the story that seem a little thin. In time, the story could unravel or you could find a glaring inconsistency. If you push on this inconsistency, you may be rewarded with even more lies or irreconcilable differences.

A very interesting technique is to begin your conversation by talking directly about how honest the other person feels they are. This cues people to be more honest later on, or at the very least you will uncover a tension between the wish to appear truthful and the act of lying. This tension could push a person to confess on their own or at least fumble their lie.

Canadian researcher Jay Olson has written extensively about the power of persuasion, and it turns out persuasive techniques can be used to great effect when trying to unmask deceptions. It makes sense—you could try and passively detect a lie in another person, or you could actively massage the truth out of them using intelligent and targeted questions, tact and persuasion techniques.

When you increase cognitive load, you are essentially giving the other person too much to think about, so their lie falls apart. A useful technique is to actually state something untrue yourself, and watch their response. Not only will this tell you what their baseline behavior is to non-truths, but the extra piece of information will be one more straw on the camel’s back. Do this a few times, switching between true and false, and you are asking the liar to juggle a lot on the spot, mentally speaking.

You could also ask them to relay a story you already know to be true, so you can surreptitiously compare their presentation to the possible lie. This is helpful if you don’t know the person well but want to get a baseline on their normal behavior.

Ask unexpected questions that will have them temporarily abandoning the rehearsed story. When they come back to it, they may have forgotten the details themselves. Take an inconsequential part of the story and repeat it back to them with an extra piece you added, or a small detail incorrect. See what they do. If they genuinely think you’d just made a mistake, they may go along with the claim for ease.

You’ve been having normal, natural conversations your whole life—try to see if you can detect any stiffness, awkwardness or unnaturalness in the story presented. If you’re far along in the conversation and the cracks are beginning to show, you might even start to directly allude to the consequences of being found lying. This can confuse and stress a person, sapping their cognitive resources and making it more and more likely they’ll make a mistake or say something truly damning.

Finally, watch how emotion is expressed during a conversation. Joe Navarro, ex-FBI agent and expert in interrogation, reinforces the importance of clusters of behavior, rather than individual observations. Behind the cognitive fact of the lie, is an emotion: guilt, nervousness, fear, or even a secret thrill at getting away with things (called “duper’s delight” by those in the know).

Lies can often be presented with a kind of cool, calm detachment. You may see the person carefully add a bit of faked emotion here and there for effect, but if you know them well, these expressions may seem a little off somehow—either the emotion seems delayed, timed strangely, last too long or are of an inappropriate intensity.

This is because the cognitive load that comes with telling a big fib can interfere with genuine expression of emotion. A person struggling to keep up with their own lie will display many of the signs and clues Navarro talks about: pursed lips, angling the body away, touching the neck or face, or ventilating—i.e., doing things to cool off, such as opening the top button of a shirt or brushing hair off the neck and face.

As you increase cognitive load by asking complex and confusing questions, you can expect to see more emotion surfacing. Keep drilling down for specifics. A great way to observe the interplay between emotion and the cognitive load of recounting a fictional narrative, is to ask directly about emotions. Many people rehearse details but don’t plan ahead with how they’re going to respond emotional (i.e., pretend!).

For example, the FBI agent might ask how someone felt to “discover” a dead body. This might take the person a while to answer (because they didn’t build this piece of info into their lie) or they may reply with no emotion or else a very unconvincing display. The truth teller will be able to almost instantly answer in a genuine way, often displaying the same emotion there and then.

Besides asking questions, cognitive overload can be utilized in another way to reveal lying. Because of how much cognitive effort goes into fabricating a narrative and keeping it up, our brain pays less attention to other facets of relaying details. For instance, if a spouse is trying to lie about where they’ve been the entire day, they will likely narrate their explanation in a way that is devoid of emotion. Details about spending time with friends which would normally be told in a cheerful and happy tone or manner will, when lying, turn into a series of objective statements from which the speaker is detached. This happens because the liar cannot simultaneously be objective in their lie yet emotional when it comes to the details of the lie. As such, try to notice the emotions that a person conveys along with their narrative and analyze whether it really matches what they’re saying. Does the narrative seem rehearsed? Would you have been more expressive than them while recounting the same details? Questions like these can help you analyze lying better.

The flip side of this vocal detachment to their narrative is that the emotional cues are then expressed more noticeably in their body language. It is extraordinarily difficult for anyone, even trained liars, to mask certain non-verbal cues when they’re lying, and these are the ones you need to detect in clusters to definitively conclude that someone is lying. Some, like facial cues, are more easily hidden. However, studies show that lying produces arousal due to the anxiety and guilt that liars ordinarily experience (unless they’re psychopaths). This makes people more susceptible to displaying non-verbal behavioral cues than they normally would be. For instance, people blink more often when they lie because of arousal. Speech disturbances, slips of tongue, pupil dilation, are more signs of lying. Moreover, the frequency of these signs is also directly correlated with the complexity of the lie. So, if a person is blinking a lot more than the average person does, the scale of their lie is probably big too.

Thus, there are two ways you can use cognitive overload to detect lying. You can patiently poke holes into their story by strategically asking the right questions, or you can try to observe specific behavioral cues that accompany lying and cognitive overload. Better yet, use them together to arrive at more accurate conclusions.

General Tips for Better-than-Average Lie-Detecting

• Sit back and let the other person volunteer information, rather than pulling it out of them. Don’t let on what you know too early—or at all.

• Stay relaxed and causal. What you are observing is not the person themselves, but the person as they are in a quasi-interrogational situation with you. So don’t make it seem like an inquisition, otherwise you may simply be watching them feel distressed about the situation itself.

• Don’t worry about individual signs and clues like touching the nose, looking up to the right or stuttering. Rather, look at how the person responds in general to shifts in the conversation, especially at junctures where you believe they may be having to concoct a story on the fly.

• Listen for stories that seem unusually long or detailed—liars use more words, and they may even talk more quickly.

• Take your time. It may be a while before you uncover a deception. But the longer the other person talks, the more chance they have of slipping up or getting their story tangled.

• Watch primarily for inconsistencies—details of the story that don’t add u, emotional expressions that don’t fit the story, or abrupt shifts in the way the story is told. Being chatty and then all of a sudden getting quiet and serious when you ask a particular question is certainly telling.

• Always interpret your conversation in light of what you already know, the context, and other details you’ve observed in your interactions with this person. It’s all about looking at patterns, and then trying to determine if any disruptions in that pattern point to something interesting.

• Don’t be afraid to trust your gut instinct! Your unconscious mind may have picked up some data your conscious mind hasn’t become aware of. Don’t make decisions on intuition alone, but don’t dismiss it too quickly, either.