My Six Discoveries#
Source: https://www.paulekman.com/blog/my-six-discoveries/
One Scientist, Six Discoveries, Fifty-Five Years of Accumulation (1955-2010)#
Discovery One: Nonverbal behavior provides accurate information. Moreover, this information is not difficult to understand; most people can effortlessly extract at least some information from it.#
It may be surprising now, but when I began my research, the prevailing consensus was that judgments based on facial expressions and body movements were at best a source of stereotypes. Clinicians knew this, but academia did not. The chair of the psychology department at Stanford University, who later became the head of the National Science Foundation, criticized me in the mid-1960s for wasting my time studying nonverbal behavior. He asked me if I had read the relevant literature and whether I did not realize how much of a waste of time it was.
My first publication documented the accuracy of certain judgments made by ordinary people through observing nonverbal behavior—regardless of whether they heard accompanying speech. I began analyzing the literature that reached completely opposite conclusions, explaining how these errors led to incorrect conclusions. My first book published in 1972, Emotion in the Human Face (ISBN 9780080166438), reanalyzed and reinterpreted sixty years of research on nonverbal behavior.
Discovery Two: There are bodily slips that leak suppressed information.#
This is a discovery, rather than a proof like the first one; it was completely unexpected and was found in my first experiment. I designed this study to verify whether nonverbal behavior could reflect the emotional atmosphere in interactions between two people. I arranged for the chair of the psychology department to criticize my classmates, one at a time, under pressure for a few minutes, and then praise them for their responses to these attacks. Thus, I obtained samples of the same person's behavior in very different emotional contexts.
One of my classmates made a "middle finger" gesture at the professor; she did not raise her finger as she usually would—this practice is typically adopted when deliberately making this gesture, referred to as "display position"—but instead placed her finger on one of her knees. She later denied making the gesture, although she admitted to feeling that way at the time. The professor said he did not see the gesture and expressed skepticism about what I said. Both were surprised when they saw the interview evidence I filmed. Since then, in a series of explorations revealing behavioral cues of deception, I found that bodily slips are among the most valuable and reliable cues. Their absence does not mean everything is fine; like other cues of deception, it is their presence that is significant.
Discovery Three: There is strong universal evidence for the emotions of certain facial expressions.#
When I began this research, I did not care whether I could find evidence of universality. Neither opponents nor supporters exceeded anecdotal evidence. I realized this was an opportunity to address a very old and important question, but time was running out. The evidence for this research had to be sought in visually isolated groups that could not learn the meanings of facial expressions through exposure to media or outsiders. I had to travel to the highlands of New Guinea in 1967 and 1968 to find these people. Two years later, contact with outsiders and Western media began to increase, but I had already obtained what I and most of the scientific community considered decisive evidence regarding the universality of six emotions: anger, disgust, happiness, fear, sadness, and surprise. I failed to study the expression of contempt, which I did not anticipate at the time (although now I know) would have a universal facial expression.
Discovery Four: A comprehensive and objective method for measuring all facial movements can be developed: the Facial Action Coding System (FACS).#
At that time, there was almost no interest in facial expressions, and thus no comprehensive and objective method for measuring facial movements. Some methods had been proposed, but they mixed description and explanation; for example, grinning, smiling, etc. No one knew, or perhaps no one cared, how many different facial expressions a person could make and which expressions were related to a person's emotional state. After failing in 1971 to create a quick measurement tool (Facial Affect Scoring Technique, FAST), Friesen and I spent six years developing a comprehensive tool based on anatomy—the FACS—for objectively measuring any action that facial muscles can produce.
Discovery Five: While deception can be detected through nonverbal behavior, most people cannot do this.#
After studying facial expressions and deception, I wondered if others could detect lies as I could. We showed video samples of people lying and telling the truth under threat of punishment to over 15,000 individuals from different professional groups. Ultimately, we found that only a few could accurately distinguish between lies and truth. The only exception was members of the U.S. Secret Service; as a group, they performed better than random guessing. Among other professional groups, the only difference was that law enforcement officers and psychiatrists were more confident, but their accuracy did not improve. Under my training on how to observe and listen, and through practicing these skills, most people could make more accurate judgments than random guessing.
Discovery Six: Some voluntarily made facial expressions can produce physiological responses of emotion.#
This completely unexpected discovery is very robust; by making the universal facial expressions we found in our research (such as anger, fear, disgust, and sadness), each of us triggered different patterns of autonomic nervous system (ANS) activity. According to Duchenne's suggestion, making the two facial movements he considered necessary for a pleasurable expression (zygomatic major and lateral part of the orbicularis oculi; in FACS terms: 6+12) did not cause significant changes in the autonomic nervous system but did produce central nervous system (CNS: EEG) activity observed in other pleasure studies. Emotion assessment theorists once dominated emotion research, believing that emotions were not genuinely produced, only physiological changes occurred, although most subjects reported that they indeed felt emotions when they made the specified facial movements.
Channels of Information for Lie Detection#
Source: https://www.paulekman.com/blog/unmasking-liars-understanding-the-clues-of-dishonesty/
Things to Watch for When Suspecting Deception#
If you want to unmask a liar, you can focus on several channels of information. These include: the liar's words, vocal cues and tone, body language, gestures, and facial expressions and movements.
Remember, there is no single clear sign of lying, but various clues can be sought in these different verbal and nonverbal communication methods.
The Liar's Words#
Among all the mentioned channels of information, liars often carefully choose their words. When preparing to lie, most liars carefully consider what they are going to say. However, carelessness, forgetfulness, or slips of the tongue may expose the liar through their words.
While we all know that speech can lie, my research has found that people generally tend to believe what others say and are often misled. I am not saying that speech can be completely ignored. People do indeed make verbal errors, and these errors provide clues of leakage and deception. Even without obvious mistakes, contradictions between verbal cues and body language, facial expressions, and vocal cues often reveal lies.
The Liar's Facial Expressions#
The face is usually the second most noticeable channel of information. This is because the face is the primary site for emotional expression, and together with voice, it may tell the listener how the speaker feels about what they are saying. Although this is not always accurate, as facial expressions can sometimes mask true feelings through emotional masks.
While liars may be aware that the face is a valuable source of information, few realize the changes in facial expressions until they become very obvious (macro-expressions). Unlike speech, the face is directly connected to areas in the brain associated with emotions, making it a rich source of information.
Facial expressions are a dual system, including intentionally chosen expressions and spontaneously produced expressions, which people may not even be aware of appearing on their faces. When people lie, their most obvious and easily seen expressions—often the ones people focus on the most—are usually false. The subtle signs of these expressions often go unnoticed, while fleeting hints of hidden emotions are typically overlooked.
Changes in the autonomic nervous system (ANS) can also be reflected in the face, such as blushing, paleness, and pupil dilation. These changes are unconscious and occur when emotions are triggered, and they are very difficult to suppress, making them very reliable cues.
One of the most helpful sources of facial leakage is micro-expressions. These expressions appear quickly and can fully display hidden emotions but are often missed. With practice, anyone can learn to interpret micro-expressions through our online training tools. You can also test your ability to interpret micro-expressions here.
The Liar's Body and Voice#
Compared to the attention given to speech and facial expressions, body language and vocal cues often do not receive equal attention. This provides lie detectors with an additional, potentially valuable source of information, as liars may not monitor these aspects closely.
Like facial expressions, voice is also connected to areas in the brain involved in emotions. When emotions are triggered, the tone and quality of the voice change, making it very difficult to disguise these changes.
The body is also a good source of leakage and deception cues. Unlike facial expressions or voice, most body movements are not directly connected to the brain areas involved in emotions. Hiding body movements may be easier than hiding changes in facial expressions or voice, but most people do not do so. People are rarely held accountable for the information revealed by their body movements. Body leakage occurs because it is often overlooked. Everyone is too focused on observing facial expressions and assessing speech.
One slip in body movements, called emblematic slips, can sometimes be a reliable cue of deception.
The autonomic nervous system (ANS) can also cause some noticeable changes in the body when emotions are triggered: for example, breathing patterns, swallowing frequency, and sweating. These body cues driven by the autonomic nervous system are difficult to control and may reveal deceptive behavior.
Deception Detection#
Source: https://www.paulekman.com/deception/deception-detection/
What is Deception Detection?#
Deception detection refers to investigative practices used to determine whether a person is honest and trustworthy. This is typically determined by considering certain behavioral and physiological cues, as well as broader contextual and situational information.
What Methods Are Used to Detect Deception?#
While historians are not entirely sure of the origins and timing of deception detection, it is clear that humans have been trying to figure out how to judge whether someone is lying for centuries.
Fortunately, these methods have undergone significant changes over time, initially shifting from unscientific tests (like the Salem witch trials) to more biologically oriented tests (like phrenology and graphology). Today's deception detection typically combines behavioral psychology (like human observation) and technology (like polygraphs and artificial intelligence).
Dr. Ekman's research in the field of deception detection primarily focuses on emotional nonverbal communication in the face and body.
Challenges of Deception Detection#
There is no single, clear sign of lying; no muscle twitch, facial expression, or gesture can definitively determine whether someone is lying. Therefore, most modern deception detection methods rely on multiple approaches to collect, analyze, and interpret emotional and physiological data.
However, any data collected merely reveals emotional cues that may be related to deception, and these cues may not be directly associated with deception. For example, during an interview, sweaty palms may indicate that the interviewee is afraid of being caught in a lie about their qualifications. Alternatively, sweaty palms may indicate that they are worried the interviewer does not believe their qualifications, even though their resume is completely honest. It is also possible that their palms are sweating due to concerns about other matters, such as a sick child at home.
In high-stakes situations, sweaty palms can have many different causes. Determining the true cause requires further investigation and analysis. It is easy to jump to conclusions, but this can harm all parties involved and must be avoided.
Do Polygraphs Really Work?#
Polygraphs operate on the same principles as detecting behavioral betrayal, and they face the same issues. Polygraphs do not directly detect lies; they only detect signs of emotion, so further investigation is still needed.
What Do Signs of Lying Look Like?#
Many observable signs are associated with lying, but not everyone will exhibit these signs. The absence of these signals does not mean a person is honest, but their presence, especially when multiple signals occur simultaneously, often suggests potential deceptive behavior.
In deception detection, a valuable aspect is first establishing a "baseline"—the behavior considered "normal" for that individual. The basic process of behavioral deception detection involves looking for cues that indicate some change or deviation from that baseline. These cues can be discovered through "hot spots" across multiple different observable channels, such as: facial expressions, body language, voice, language style, and language content.
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What Are Hot Spots?#
Dr. Ekman coined the term "hot spot" to refer to certain signs that indicate something is amiss; either that the whole story has not been told or that the details of the story have been altered. Hot spots signal some emotional or cognitive pressure; however, importantly, they do not reveal specific reasons. Further investigation and consideration of context are needed to validate your hypothesis.
Typical hot spots include:
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Deviation from baseline (for example, a normally talkative child being unusually quiet when asked about a broken vase)
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Brief conflicts between verbal communication and nonverbal expression (for example, assuring someone that you are not angry with them while clenching your jaw and raising your voice).
Facial Cues of Deception#
Micro-expressions#
When lying, the face typically contains two types of information—the information the liar wants to convey and the information the liar wants to hide. Usually, these hidden emotions leak out in the form of micro-expressions, which are brief (half a second or less), involuntary facial expressions that reveal true emotions.
Although Dr. Ekman cautions that a single micro-expression or leaked moment does not provide conclusive evidence of lying, micro-expressions are one of the most effective nonverbal behaviors for monitoring whether someone is being dishonest.
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False Expressions#
Any emotional expression can be faked and/or used to mask other emotions. Among all emotions, research shows that commonly faked emotional facial expressions are asymmetrical. Some genuine expressions are asymmetrical; it’s just that most are not.
In fear or sadness, a clue that an emotion is being faked is the lack of reliable forehead expressions.
A key clue that a happy expression is false is the absence of muscle engagement around the eyes when smiling. When the muscles around the eyes (lateral part of the orbicularis oculi, in Latin orbicularis oculi pars lateralis, FACS term AU 6) are not active, it is possible to distinguish between fake smiles and genuine smiles. This difference can sometimes be difficult to discern, and most of the time, we can easily be deceived by a fake smile, which may also explain why it is such a common emotional mask.
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A lie detector should never rely solely on a single cue of deception; multiple cues must be present. Facial cues should be confirmed by vocal, linguistic, or bodily cues. Even within the face, no single cue should be interpreted unless it occurs repeatedly and preferably confirmed by another facial cue.
Why Is Dr. Ekman Considered the World's Leading Human Lie Detector?#
Dr. Ekman is indisputably the leading expert in human emotions and nonverbal expression. His research in both fields has an intrinsic connection to the science of deception, and thus he has accumulated a wealth of insights and expertise in the field of deception.
However, Dr. Ekman does not consider himself a human lie detector; he states that no one can perfectly master the art of lie detection. He advocates that through more skills and data, we can make more confident judgments, although it is important to remember that we can never determine with 100% accuracy whether someone is lying.
Although Dr. Ekman rejects the title of "human lie detector," it is easy to understand why others still refer to him as such. As a consulting expert, Dr. Ekman works closely with top security and counter-terrorism agencies worldwide, including the FBI, CIA, and Scotland Yard. His expertise has even attracted the attention of Hollywood elites, leading to the creation of the hit television series Lie to Me.
To prevent government or private entities from monopolizing this knowledge, Dr. Ekman has transformed his research findings into publicly accessible online training tools.
Lie to Me#
Source: https://www.paulekman.com/projects/lie-to-me/
Dr. Ekman and Dr. Cal Lightman#
Dr. Ekman served as a scientific consultant for the television series Lie to Me. He analyzed and critiqued the scripts of each episode and explained the scientific principles of deception detection to the actors and crew.
The main character, Dr. Cal Lightman, is somewhat based on Dr. Ekman. Many plotlines in the series Lie to Me reference Dr. Ekman's personal experiences.
While Dr. Ekman's research greatly influenced the character of Lightman, Lightman's personal characteristics are not based on Dr. Ekman. For example, Lightman is British, divorced, and has a strained relationship with his only child. In contrast, Dr. Ekman is American, has been married for over thirty years, and has a good relationship with his two children.
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