Former FBI agent Mark Bouton lists twelve signs that someone may be lying: darting eyes, rapid blinking, long eye closures, three kinds of eye movement to the right, a smile that does not reach the eyes, face touching, pursed lips, sweating, blushing and head shaking that contradicts what is being said. They are easy to remember and often repeated. The problem is that decades of research show none of them reliably reveals a lie. Most are signs of stress, and honest people under pressure show them too. Here is each sign, what Bouton says about it, and what the evidence says.
Who Mark Bouton is
Bouton spent about thirty years as an FBI agent and is credited with helping to identify Timothy McVeigh as a suspect after the Oklahoma City bombing. That attack, on 19 April 1995, killed 168 people, including 19 children, and injured roughly 680 more. McVeigh was arrested about ninety minutes after the blast, when a state trooper stopped him for driving without a licence plate, and he was executed in June 2001.
After leaving the Bureau, Bouton wrote mystery novels and the guide "How to spot lies like the FBI". In a 2016 interview with Business Insider he explained that the signs have different causes, saying, "Some are caused by nervousness, some by chemical reactions, and others by physical reactions." His method is more careful than the list suggests: watch how a person behaves during relaxed small talk to establish a baseline, then look for clusters of changes when the pointed questions begin.
The eye signs (1–6)
1. Eyes darting back and forth
Bouton links shifting eyes to feeling trapped, a leftover of looking for an escape route. Yet the belief that liars avoid eye contact or look around nervously is one of the most widespread myths in the field. Reviews of lie-detection studies find that liars and truth-tellers show these behaviours at similar rates.
2. Rapid blinking
Bouton says people normally blink five or six times a minute and that a liar may blink several times in quick succession. The baseline figure is too low: adults blink about 17 times a minute on average, and much less while reading or concentrating. Stress can change blink rate, but some studies suggest liars blink less while they are concentrating on a story, then more afterwards.
3. Closing the eyes for a second or more
A normal blink lasts roughly a tenth to four-tenths of a second. Bouton reads longer closures as a way of shutting out an uncomfortable question. People also close their eyes to think, to remember or simply because they are tired, so a long blink tells you little on its own.
4–6. Looking up, sideways or down to the right
Bouton's three right-side signs all come from one idea: that a right-handed person looks to their left when recalling something real and to their right when inventing it, whether the memory is visual, a sound or a physical sensation, with left-handed people reversed. This idea comes from neuro-linguistic programming, a self-help movement of the 1970s, and it has been tested directly. In a study published in PLoS ONE in 2012, psychologist Richard Wiseman and colleagues found that liars and truth-tellers in a lab looked left and right about equally. A second experiment, using video of public appeals by people later convicted of harming a missing relative, found the same thing. Eye direction does not reveal lies.
Face and body signs (7–12)
7. No wrinkles beside the eyes
Bouton notes that a real smile bunches the skin under the eyes and creates crow's feet. This part is grounded in research on facial expression: a genuine, or "Duchenne", smile engages the muscles around the eyes, while a polite smile often uses only the mouth. But a forced smile shows politeness or discomfort, not necessarily dishonesty.
8. Touching the face
According to Bouton, lying causes a chemical reaction that makes the face itch. There is no good evidence for a lie-specific itch. Face touching is a common self-soothing gesture when people feel anxious or awkward, for whatever reason.
9. Pursed lips
Stress can dry the mouth, and people may purse or lick their lips in response. That is genuine physiology, but it follows anxiety, not deception as such.
10. Sweating
Sweat on the forehead, cheeks or neck is another stress reaction controlled by the nervous system. Heat, illness, caffeine and simple fear of being disbelieved can all produce it.
11. Blushing
Blushing is an involuntary response driven by the sympathetic nervous system, the same system behind the "fight or flight" reaction. People blush from embarrassment, attention or being accused, which is exactly when an innocent person might colour up.
12. Shaking the head while saying "yes"
Bouton points out that people usually nod along when they say something they believe, so a head shake that contradicts the words may reveal a mismatch. This kind of inconsistency between words and gestures can be worth noticing, but cultural differences and personal habits mean it is far from proof.
What research says about spotting lies
The most quoted figure comes from a 2006 review by psychologists Charles Bond and Bella DePaulo of more than 200 studies: people correctly sorted truths from lies only about 54 percent of the time, barely better than tossing a coin. Police officers, customs agents and other professionals did not do much better than anyone else, and in one large screening of around 13,000 people, only a few dozen showed a real talent for spotting lies.
The behavioural differences between liars and truth-tellers are small and inconsistent. If anything, studies suggest liars may move less, blink less and make fewer speech errors, perhaps because they are trying hard to control themselves. Overall impressions tend to work better than single cues: statements that sound uncertain, vague or implausible are more often false, while consistent, detailed and spontaneous accounts more often turn out true.
The danger of a checklist is that it targets nervousness, and nervous people are not necessarily dishonest. Being suspected of lying is stressful in itself. Psychologist Paul Ekman called this trap the Othello error, after Shakespeare's hero, who read his innocent wife's fear as proof of guilt.
Better ways to judge whether someone is honest
- Know the baseline. Compare a person's behaviour with how they usually act, not with a generic list.
- Look for clusters and changes, not single signs, and treat any change as a reason to ask more, not as a verdict.
- Ask open questions. Invite a full account in the person's own words, then ask for specific details. True stories tend to hold up under follow-up questions better than invented ones.
- Check the facts. Independent evidence, such as records, receipts or other witnesses, is far more reliable than body language.
- Stay fair. Avoid accusing anyone based on blushing, sweating or eye movements alone, especially at work or in personal relationships.
The twelve signs at a glance
- Darting eyes, face touching, pursed lips, sweating, blushing: signs of stress, shown by honest and dishonest people alike.
- Rapid blinking and long eye closures: blink patterns can change under stress, but not in a way that reliably marks a lie.
- Eye direction (up, sideways or down to the right): tested and found not to indicate lying.
- Smile without eye wrinkles: may show a polite or forced smile, not necessarily a lie.
- Head shaking that contradicts the words: a mismatch worth noticing, but only as a prompt for further questions.
Bouton's list is a useful reminder to pay attention, but the research is clear: the best lie detector is careful questioning and checking the facts.
Sources: Business Insider: How to tell someone's lying to you by watching their face; Encyclopedia.com: Mark Bouton; Smithsonian: Looking left or right doesn't indicate if you're lying; The Jury Expert: Looking for lying in all the wrong places; Wikipedia: Blinking; Wikipedia: Oklahoma City bombing.
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