Pinocchio grew a long nose when he lied. Although few people expect to see a nose visibly change when someone lies, many believe that nonverbal behaviors provide clues to a person's honesty. A nose scratch. A mouth cover. Hang wringing. Leg tapping. Over the years, different claims have been made about these and other nonverbal behaviors as possible cues to deception. Do these nonverbal "tics" really mean that a person is lying?
Deception detection is a huge area of behavioral science and can inform such questions. For example, many people believe liars avoid eye contact when lying. But looking away when answering questions (gaze aversion) has not been scientifically validated as a sign of deception. The idea that people avoid eye contact when lying is more a myth than reality, a myth that is believed around the world despite being largely disproved by science. In fact, liars are more likely to look interviewers in the eye when answering in order to appear honest.
What Does the Research Show?
For decades, many prominent researchers searched for the single behavioral tell that was a cue to deception. But a seminal meta-analysis published two decades ago provided ample evidence that there is no one, single telltale sign of lying. Pinocchio doesn't exist.
Research and application in this area is difficult because the verbal and nonverbal indicators of veracity and deception are complex, varied, and unique to individuals. Cues don't always mean the same thing in different people or even in the same person at different times.
Furthermore, nonverbal behaviors can signal many different mental states beyond veracity and deception, such as discrete emotions (anger, disgust, or fear), general affective states (open or closed, relaxed or tense), specific verbal words or phrases, and cognitive processes (confusion, concentration).
Fortunately, many studies published since that meta-analysis have demonstrated that nonverbal behaviors can differentiate truthtellers from liars. These studies diverge from earlier research partly because they approximate real-life situations in which catching people lying is important and has real consequences.
The research to date points to this conclusion: cues to deception (and veracity) do exist and can occur in multiple channels of behavior—face, hands, body, verbal style, or verbal content. Specifically, certain nonverbal behaviors have been scientifically validated as deception indicators while others have not. Facial expressions of emotion and microexpressions, some gestures, fidgeting (in some contexts), and some aspects of voice differentiate truthtellers from liars. Moreover, some behaviors are indicators of veracity while others are indicators of deception, and all behaviors must be interpreted in context.
Using the Science to Improve Understanding of Others
How can people leverage this area of science in their daily lives? First, learn about the world of nonverbal communication and nonverbal behavior, and all the various mental states that are signaled by which behaviors. For example, specific facial expressions of emotion can be signaled by face and voice; specific cognitions and cognitive processes can be signaled by face, voice, and gesture; and general affective states can be signaled by specific body movements. Important information can be gleaned from others without them speaking. With words, nonverbal behaviors can complement, supplement, qualify, and contradict words. Learning to read and interpret these behaviors well can provide important insight into the minds of others and improve communication overall, aside from making judgments of veracity or deception.
People who want to detect deception could learn how to read microexpressions—extremely brief (faster than half a second), involuntary, unconscious facial expressions of emotion. Most people don't see them, and those who see them see something but don't know how to interpret them. Microexpressions signal concealed, suppressed, or repressed thoughts and feelings. Being able to identify microexpressions when they occur can provide people with important cues to others' mental states beyond the spoken word.
Learning to ask good questions and to listen more than one talks is critical, as is honing active listening and observational skills. When trained on scientifically validated indicators, professionals and laypersons alike get better at detecting deception. People can learn to be more sensitive to other people's states of mind, including when they are telling lies or truths, by listening more and paying attention to their deeds as well as their words.
For Further Reading
Matsumoto, D., & Wilson, M. (2023). Behavioral indicators of deception and associated mental states: Scientific myths and realities. Journal of Nonverbal Behavior (Special Issue on Innovations in Nonverbal Deception Research). https://doi.org/10.1007/s10919-023-00441-w
Matsumoto, D., & Wilson, M. (2023). Incorporating consciousness into an understanding of emotion and nonverbal behavior. Emotion Review, 15(4), 332-347. https://doi.org/10.1177/17540739231163177
Frank, M.G., Svetieva, E. (2015). Microexpressions and deception. In: Mandal, M., Awasthi, A. (eds) Understanding Facial Expressions in Communication. Springer. https://doi.org/10.1007/978-81-322-1934-7_11
David Matsumoto is Professor of Psychology at San Francisco State University and Director of Humintell, a company that engages in research, consultation, and training in investigative interviewing, threat assessment, social influence, and cross-cultural adjustment.
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