Whether going out on a date, traveling through a foreign country or interrogating a suspect in a crime, forensic psychology offers a wealth of tools to help decode people’s nonverbal behavior. These cues include gestures, vocal tones, body positioning, micro-expressions of the face, and often subconscious indicators of people’s internal states.
This guide offers a summary of some of the findings from well-established psychologists and legal experts. From Paul Eckman’s groundbreaking facial expression research to former FBI expert Joe Navarro’s findings of body language, this discipline can elucidate the less literal aspects of human communication.
Psychologist Dr. Paul Eckman is a legend in the world of deciphering facial expressions. Based on more than 50 years of research, Dr. Eckman has pioneered a coding system for people’s emotional displays involving hundreds of combinations of facial muscles, often scientifically correlated with distinct emotional states. He calls each observable facial movement an “action unit” or an AU and offers some online tools to help people gain mastery in decoding facial signals.
One of his main contributions to the research is micro-expressions, brief flashes of emotions revealed on one’s face. This training has been used by lie detection experts, actors, and Homeland Security officers.
So what are some of the telltale signs?
Science of People (2021) gives a thorough, introductory summary of Dr. Eckman’s work:
Contempt or hate
Aspiring forensic psychologists can sharpen their skills in identifying microexpressions through Dr. Ekman’s online Micro Expressions Training Tools course. Used by many Fortune 500 companies and individuals, this course teaches how to respond effectively to facial expressions in law enforcement and other workplace and personal environments. The goal of this program is to increase individuals’ abilities to increase emotional awareness and detect deception. The course is available in English, Spanish, and Portuguese.
Joe Navarro, a 25-year FBI veteran in counterintelligence agent, best-selling author, is an expert on body language and non-verbal communication. He writes on his blog JNForensics.com (2020) that many of the behaviors people typically associate with lying—avoiding eye contact, looking up to one direction, touching one’s face, clearing one’s throat—don’t indicate deception. He adds that even experts in the field can only tell if someone is lying roughly 60 percent of the time, slightly better than chance.
That said, Navarro has learned a lot from his 44-year-long career in detecting people’s inner lives from their comportment. And while he supports the validity of Dr. Ekman’s and other scholars’ research on micro-expressions, he makes the case that people’s entire body language reveals a more holistic expression of the truth. In his book Clues to Deceit, Navarro asserts more than 215 behaviors are linked to psychological discomfort, but most of them are not detectable in facial expressions alone.
Specifically, Navarro notes that the truth can be revealed in people’s feet. He uses two examples from his book “What Every Body is Saying” to show that the positioning of someone’s feet can show they are eager to leave or suppressing agitation. For example, if someone appears friendly, but their foot is pointing in the direction of the nearest exit, this is a body language cue that someone needs to leave even if their face indicates otherwise.
As well, a person may appear calm and friendly but showing signs of agitation if they are repeatedly rolling their body weight to the outside of their feet. Why do facial and feet expressions not correlate? Bound by social manners or deceit, humans may present information in a socially acceptable way using the prefrontal cortex. Still, our limbic system, the most primitive part of the human brain, can override the desires of the prefrontal cortex. These examples of feet direction and movement show how the limbic system expresses the truth within the body more accurately than a facial expression.
Moving up from the feet, Navarro shares another telltale sign he observed when interviewing suspects: innocent suspects stayed cool. In contrast, guilty suspects moved their bodies in an attempt to cool off. He calls these “ventilating behaviors,” which include running fingers through hair multiple times, lifting or repositioning hats to increase airflow, pulling at shirt buttons or lifting a shirt away from the chest area, pulling at collars, or even untucking and retucking shirts to cool off. Yawning, the kind that draws in cool air quickly with an inhale, is also a ventilating behavior to notice when wondering if someone is telling the truth or not.
Moving up the body, Navarro highlights the correlation between people touching their necks and chins and not telling the truth. This is an automatic pacifying action people use to soothe themselves when presented with stressful situations. In general, men tend to grab and massage their necks and chins while women delicately touch their “suprasternal notch,” or neck dimple, the round place between the collarbones that joins the neck to the chest.
Navarro once interviewed the mother of a fugitive on the run who was considered armed and dangerous. The woman answered his questions but touched her neck dimple each time he asked if her son was in the house. Each time she said no, but when he asked permission to search her home, he found her son hiding in a closet.
Informed by the work of Navarro, here is a breakdown of some body language cues neatly summarized in a report in Entrepreneur:
When reading into facial and body language cues, it’s important to remember that culture, neurodiversity, and psychological conditions can play a big part in how emotions are expressed—or not expressed.
According to Dr. Emily Cook, a marriage and family therapist, non-verbal communication is universally valued over verbal communication (as reported in Healthline 2020), but it’s also important to remember that cultures place different values on spoken and non-verbal communication and certain neurological or psychological conditions. Not being aware of these conditions can unnecessarily erode trust between people. Here are some examples of how non-verbal communication can appear from diverse perspectives from Healthline.
Eye contact in Western countries conveys respect while in many Eastern countries it’s considered disrespectful or rude depending on age and cultural hierarchy.
Greetings also convey many cultural differences; some cultures greet each other with handshakes, hugs, and cheek kisses while others greet each other with bows, hands in prayer position, or a simple chin nod without touching other people out of respect for their personal space.
Neurodiverse is a term used to describe people who are autistic. For neurodiverse people, fidgeting or not making eye contact may be a self-soothing response to cope with a situation that is overstimulating or unfamiliar.
People with psychological disorders may find it difficult to interact with peers in a way that follows cultural norms and expectations. People coping with anxiety or trauma may find verbal interactions difficult and may prefer not to touch anyone or be touched by other people.
While these research-backed cues to non-verbal communication can shine a light on what people are thinking, it’s essential to consider the context as well. Those who are shy, for instance, may display signs of discomfort that can be misconstrued as other negative emotions such as disgust or anger.
According to Navarro, it’s also crucial to establish trust or rapport with a person before trying to detect deception. He recommends that this baseline of more comfortable behaviors is important to establish a metric for more unusual facial expressions or body language patterns.
For further research on the meaning of non-verbal behaviors, the books and blogs of Dr. Paul Eckman and Joe Navarro, M.A. provide a comprehensive, research-backed overview, from head to toe.
Jocelyn Blore is the chief content officer of Sechel Ventures and the co-author of the Women Breaking Barriers series. She graduated summa cum laude from UC Berkeley and traveled the world for five years. She also worked as an addiction specialist for two years in San Francisco. She’s interested in how culture shapes individuals and systems within societies—one of the many themes she writes about in her blog, Blore’s Razor (Instagram: @bloresrazor). She has served as managing editor for several healthcare websites since 2015.