Friends of the Nonverbal Communication Blog, this week we present the paper “Strong, but Wrong: Lay People’s and Police Officers’ Beliefs about Verbal and Nonverbal Cues to Deception” by Bogaard, G.; Meijer, E. H.; Vrij. A. and Merckelbach, H. (2016),in which authors carry out a study to know how are police officers’ and civilians wrong about the cues to detect deception.
Deception is the main character of nonverbal communication. There are studies that report that we tell about two lies a day. However, more recent studies have shown that there are many differences at individual levels when it comes to lies and that idea cannot be considered absolute.
Despite this, what all the research says is that we have a lot of experience when it comes about lying and being lied, and yet our ability to detect deception is rarely above the level of chance, including for the police.
One possible explanation may be that people often have incorrect beliefs about what cues are sign of deception. For example, the belief that liars tend to look away has been proven flawed, but most people still trust it. Strömwall and Granhag reported that gaze aversion and increased body movement were strong signals of deception for police, judges, and prosecutors.
People tend to rely heavily on nonverbal cues when delivering verdicts of deception. However, numerous research shows that deception cannot be reliably inferred through only behavior. We also need to pay attention to verbal cues.
Masip (who has been, in several occasions, one of the professors of our master’s degree in Nonverbal Communication and Lie Detection) and Herrero conducted a study in which they asked police officers and civilians how lies could be detected. Both groups mentioned that they relied primarily on nonverbal cues.
Because people tend to rely on nonverbal cues, verbal content is often largely ignored, despite research showing that diagnostic accuracy can be improved when content is trusted. Surprisingly, little research has investigated the beliefs about these types of cues.
Some truth evaluation methods have been developed that are based specifically on the content of a claim, such as criteria-based content analysis (CBCA) or reality monitoring (RM).
The CBCA consists of 19 criteria that are expected to be more present in true statements than in fake ones. For example, there is evidence that liars tend to tell a less coherent story and are less likely to make spontaneous corrections to their stories. Also, they tend to describe fewer replays of conversations.
The CBCA was originally created to assess children’s testimonies in cases of alleged sexual abuse but has been successfully used in numerous studies with adults in different contexts.
The RM is used to analyze whether a memory is originated from a real experience or an imagined event. The reason for this is that a memory made of a real experience arises from perception and, consequently, will contain more sensory, contextual and affective information than memories that originate in the imagination.
Support has been found in previous studies for some RM criteria, for example, that liars include less perceptual, spatial, and temporal information in their stories, and that liars’ stories are less plausible than true stories.
In the study we are talking about, authors explore participants’ views of verbal and nonverbal cues through open questions, and to further examine their views of verbal cues, they were asked a series of closed questions, obtained from the CBCA and the RM.
The sample consisted of 95 police officers and 104 university students from the Netherlands. Police officers were professional detectives or interrogators with an average experience of 22 years.
When the students and police officers were given the opportunity to list the cues that they believed indicated deception, they spoke of stereotypical, unscientifically unsupported nonverbal cues, such as gaze aversion, nervousness, exaggerated movement, or sweating.
In addition, they mentioned more nonverbal than verbal cues for diagnosing lying, which is in line with previous research.
In the open questions, police officers mentioned fewer clues than the students in general, but among those they did mention, verbal clues predominated.
Most of the behavioral signs mentioned by the participants are based on the idea that lying makes liars anxious, and this anguish is shown in their facial expressions (they blush, sweat, blink…), or in their gestures (they are restless, their body moves, illustrative gestures appear…). However, people underestimate the importance of situational factors that can influence someone’s behavior. For example, truth tellers may also be nervous for reasons apart from deception, if, for instance, the style of the interview is intimidating, or they are afraid of not being believed.
Police officers are more cautious when it comes to talking about signs of deception, probably because making mistakes in their jobs is more serious for them than for the students interviewed.
Probably, these beliefs are so persistent due to the lack of feedback. In other words, no one confesses whether they have actually been lying after an interview, much less in a police environment.
A limitation of the study is that only beliefs about lying were investigated and the actual deception detection performance was not observed.
Although several studies have already shown the dangers of relying on stereotypical nonverbal cues, the current study reveals that people still believe these cues are useful in unmasking liars.
For professionals, these beliefs are especially harmful. Being aware of them might be enough to gradually shift their attention to verbal cues, which, based on the findings of this article and previous literature, should be more precise.
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