Watch for inappropriate, unusual, or uncommon behavior. Also watch for common liars' mistakes like mismatching words and body language. They might say “no” while nodding “yes.” They could exhibit strange emotions (laughing when the subject is serious, for example).
The polygraph is the best-known technique for psychophysiological detection of deception. The goal of all of these techniques is to detect deception by analyzing signals of changes in the body that cannot normally be detected by human observation.
Interviewers can enhance their ability to detect deception by focusing on four areas of nonverbal behaviors: comfort/discomfort, emphasis, synchrony, and perception management.
Vocal tone is a powerful indicator of emotion – research has shown that a person's vocal tone will waver from the baseline in up to 95 percent of all deceptive statements.
The direction of their eyes: A 2012 study published in Plos One debunked the myth people look to the left when lying. A study by the University of Michigan found when participants lied, they maintained eye contact 70% of the time.
When it comes to detecting lies, people often focus on body language “tells,” or subtle physical and behavioral signs that reveal deception. For example, shrugging, lack of expression, a bored posture, and grooming behaviors such as playing with hair or pressing fingers to lips can give away a person who is lying.
Nonverbal cues are clues of deceit that are expressed through facial expressions, eye movements, and body language. Verbal cues are linguistic clues of deceit that are expressed in an individual's statement, such as stuttering, differentiation in pitch, etc.
Detecting a lie is not always as easy or straightforward as noticing unusual body language or behavior. However, the following are signs that could possibly be present if someone isn't telling the truth or they are withholding information: Avoiding eye contact. Being vague, or offering few details.
Lie detection commonly involves the polygraph, and is used to test both styles of deception. It detects autonomic reactions, such as micro-expressions, breathing rate, skin conductivity, and heart rate.
Remembering the baseline for a particular person, look for behaviors that deviate from that baseline. Also watch for common liars' mistakes like mismatching words and body language. They might say “no” while nodding “yes.” They could exhibit strange emotions (laughing when the subject is serious, for example).
The researchers found that active deception detection requires three things: gathering information to fact-check the communication content, strategically prompting deception cues, and encouraging honest admissions and discouraging continued deceit.
The first attempt to use a scientific instrument to detect deception occurred around 1895, when Lombroso applied a blood pressure instrument (hydrosphygmograph) to criminal suspects.
Research has consistently shown that people's ability to detect lies is no more accurate than chance, or flipping a coin.
Itching and fidgeting: Rocking the body back and forth, cocking the head to the side or shuffling the feet can also be signs of deception, says Glass, who completed a post-doctoral fellowship at UCLA focusing on Psychology and Verbal and Non-Verbal Communication.
In the literature on cues to deception, as in everyday life, lies about personal feelings, facts, and attitudes are the most common- place. Participants in studies of deception might lie about their opinions on social issues, for example, or about their academic interests or musical preferences.
There are many signs someone could be lying. For example, one may make too little or too much eye contact, sweat or flush in their face, fidget or enact unusual gestures, have trouble maintaining normal speech patterns, and have difficulty controlling the volume and tone of their voice.
Look for flared nostrils, lip biting, rapid blinking or sweating. These changes in facial activity signify an increase in brain activity as a lie begins. Some people will get a slight flush to their face when they are lying, so look for blushed cheeks as anxiety may set in.
Liars also tend to tense up when they're not being truthful, and this can include tightening the jaw and forehead. Both are connected to the "mental effort and stress" associated with telling a lie, according to Wenner. "They concentrate harder on what they're saying than simply telling the truth," she explains.
Deception can be found in the strangest of ways, some of which involve fidgeting and itching. “The head will be retracted or jerked back, bowed down, or cocked or tilted to the side,” behavioral analyst and The Body Language of Liars author Dr. Lillian Glass previously wrote.
Glancing upwards often suggests that a person is bored. It may mean that they are looking at their surroundings to find something that stimulates them more than the conversation they are currently having.