deception detection


Friends of the Nonverbal Communication Blog, this week we present the paper “Looking guilty: Handcuffing suspects influences judgements of deception”, by Zloteanu, M.; Salman, N. L.; Krumhuber, E. G. and Richardson, D. C. (2022), in which authors carry out a study with police officers and civilian citizens to know how does the fact that suspects are handcuffed or not to the interviewers’ judgment.

Detecting deception may be crucial in forensic investigation contexts, where the judge’s and/or jury’s decision may depend on the credibility of victim, witness or suspect’s testimony. 

However, truthfulness trials are a major challenge, especially for those whose decision is the one that will condemn or acquit a defendant. 

As we have discussed several times before, people tend to be bad at detecting lies. Our judgment is biased toward overestimating the honesty of others and relying too much on ourselves. 

Given the enormous importance of these judgments in the legal context, it is vital to examine the role of situational factors in this process. 

For this reason, authors decided to use an experimental scenario in which they simulated a real interrogation. They handcuffed some people who were to play the role of suspects, and examined how this might affect the truthfulness judgments of those who had to decide whether the suspect was lying or not.

Before explaining the study and the conclusions, the authors give a brief review of the existing literature. 

The reality is that those who make these truthfulness judgments (hereafter we will call them “judges”) do so with poor quality. This is something that has been attributed, in part, to the lack of reliable behavioral cues that differentiate liars from truth-tellers. 

For example, people believe that liars touch themselves more, move more, tend to look away, and are generally anxious and nervous. However, these beliefs rarely match reality. 

In fact, one of the reasons the authors chose this topic for their study was that, according to studies from 2006, 2007 and 2004, liars tend to make fewer hand and finger movements and use fewer illustrative gestures compared to those who tell the truth. Therefore, the idea of restricting the movements of “suspects” in this study may have an impact on the discriminability of liars and truth-tellers. 

That is, in this case, the reality contrasted by different studies is contrary to popular belief.

On the other hand, the literature on deception detection has largely overlooked the impact of situational factors (external elements that influence the process) on liars and truth-tellers. That is, the situation in which they find themselves can affect their behavior. 

For example, manipulating people’s clothing can affect the judges’ empathy for the suspect. And wearing glasses can increase the judge’s perception of the suspect’s intelligence, honesty, and trustworthiness.

Authors decided to include police officers in this study because research with police professionals is often scarce in the field of deception detection. 

The available data suggest that police officers show similar performance to other citizens regarding this matter. This may be due to police officers relying on signals to determine deception that are not entirely correct. 

In the study at hand, a number of 83 people were obtained who would take the role of “judges”; of these, 23 were police officers. The suspects were 19 persons, who were randomly distributed into two groups: handcuffed and uncuffed persons. 

Prior to interrogation, the suspects completed four items from a questionnaire used to measure individual differences in Machiavellianism. Subsequently, two of these four responses were modified so that the suspect had two honest and two dishonest responses.

Afterwards, they were allowed to read the modified responses and were instructed to justify them to the interviewer when the time came. 

As expected by the authors, it appears that the handcuff manipulation affected both police officers and those who were civilian citizens. Statements made by handcuffed suspects were more difficult to classify for both groups. That is, the probability that a handcuffed suspect would be misclassified in terms of the truthfulness of his or her statement was nearly 65%.

One result that the authors found troubling was that police officers showed greater confidence in their decisions without being more accurate than the civilian citizen group.

Overall, both police and non-police officers performed worse on their task when the suspect was handcuffed, supporting the authors’ assertions that situational factors can negatively affect.

That is, the results illustrate that situational elements can affect people’s perception and judgment. Reducing the impact of these factors could improve forensic practices and, more importantly, deception detection procedures, while reducing the risk of potential miscarriages of justice. 

Authors recommend that future research along these lines should be devoted to studying in more depth how exactly it affects whether or not the suspect is handcuffed when it comes to making truthfulness judgments. They also note as very interesting a focus on the suspect’s ability to gesticulate.

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Friends of the Nonverbal Communication Blog, this week we present the paper “Intentional-Deception Detection Based on Facial Muscle Movements in an Interactive Social Context”, by Dong, Z.; Wang, G.; Lu, S.; Dai, L.; Huang, S. and Liu, Y. (2022), in which authors carry out a study using the facial electromyography technique to study the facial muscles that may be associated with deception.

Deception detection has been a social topic of interest throughout human history, in which facial expressions have played a key role. 

The face can be used as a clue to interpret the mental activity of a person and, therefore, it may be useful to know if we are facing an honest speech or not. 

We have already mentioned that there are two types of facial expressions, depending on their duration: macroexpressions and microexpressions. Macroexpressions are more frequent, last longer and are, therefore, easier to control and suppress. Microexpressions, on the other hand, are brief, subtle and more discreet. They are born from a failed attempt to hide or suppress emotions. Thus, they are believed to be the most reliable clues for detecting lies and dishonesty. Ekman argued, on this subject, that uncontrollable and quick muscle movements in the forehead area could be important clues to detect lies.

One of the techniques with the highest success rate for the study of microexpressions and their relationship with lying is the analysis of facial expressions on video. However, in this type of analysis an algorithm is needed to classify expressions, for instance, using facial action units (AUs), making manual annotation somewhat necessary. 

The truth is that the accuracy of humans in deception detection does not usually exceed randomness, based on previous research, reaching just over 50% accuracy. But what happens if we use computerized means? According to experts, accuracy would increase to approximately 70%. 

These computerized means, such as the polygraph, normally focus on analyzing physiological responses like facial temperature, pulse, heart rate, blood pressure… It is understood that the liar will suffer moments of emotional stress because he/her will be frightened, nervous and anxious when lying, and that is precisely what these indicators relate to.  

The problem is that innocent people who tell the truth may also be frightened and nervous in a situation where their honesty is being judged. Therefore, this method is not completely reliable. 

Other lie detection studies have relied on brain imaging techniques, such as electroencephalography, and have had very positive results. However, this method requires the use of inaccessible sensors and machinery. 

In recent years, facial electromyography has been proposed as a method to investigate facial muscle movements and their association with lying. It has had positive results, although its usefulness in this field needs to be further explored. 

This is precisely the method of analysis tested by the authors of the article, who carried out an experiment with 22 volunteers who were divided into pairs.

The activity consisted of a role-play: one of the two people would be the informant and the other would be the detective. The detective would ask a series of simple autobiographical questions, and others more extensive about personal preferences. In a second stage of the experiment, the roles were exchanged and finally, in a third stage, the subjects tried to recognize who was lying and when. While this was going on, the participants underwent facial electromyography. 

Authors obtained several interesting insights. First, it looks like humans tend to use the zygomatic muscle for expressions associated with positive emotions and to hide emotions while lying

On the other hand, the corrugator muscle was associated with expressions related to negative emotions (for example, frowning). 

Besides, most interestingly, it seems that those who lied in this experiment had a higher activity of the zygomatic muscle.

Therefore, since this muscle is associated with expressions of positive emotions, the authors infer that the liars may be experiencing some joy due to having succeeded in their lie. 

One idea that would support this proposal of the authors is the Duchenne smile, which, with zygomatic muscle activation, is an indicator of happy emotions. 

Both the zygomatic muscle and the corrugator muscle are located in the upper facial area and the muscles in this area are subject to less volitional control by the motor cortex that is responsible for their movement. As a result, some researchers believe that when people lie, their upper facial muscles filter out emotions more easily. This idea would be supported by the results of the authors’ experiment, which, while inviting further research on the subject, yield revealing information that should be taken into account. 

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Friends of the Nonverbal Communication Blog, this week we present the paper “No evidence that instructions to ignore nonverbal cues improve deception detection accuracy”, by Bogaard, G. and Meijer, E. H. (2022), in which authors carry out a series of experiments to know whether, when somebody receives the order of ignoring the nonverbal behavior of other person, effectively, he/she does, and pays more attention to verbal cues, making it easy the deception detection process, and doing it more effectively. 

When people are asked what they look for in a person when trying to unmask and uncover their lies, most of them answer that they pay attention to nonverbal signs such as gaze aversion or general nervousness.

People believe that such nonverbal signals are the most difficult to suppress and control, more so than verbal signals, therefore, they are very useful in detecting lies. 

This belief that nonverbal cues are a foolproof diagnostic method for deception diagnoses is common in most countries. Even dedicated experts such as police officers, correctional officers, probation officers, prosecutors or judges strongly believe it on many occasions. 

However, this belief is at odds with empirical research, which shows that the relationship between nonverbal cues and deception is actually weaker than we think. 

Knowledge of nonverbal communication cues is useful in many areas, but empirical evidence has shown that paying attention to them alone is not the most reliable method of catching a liar.

Judges and prosecutors are often warned not to pay attention to whether a witness looks away, moves, is nervous, or speaks too fast, as these signals may lead us to errors. 

Even police departments around the world, such as the Dutch police, expressly advise officers that stereotypical nonverbal cues do not indicate deception and therefore should not be used to make credibility judgments. 

Based on legal research, there is reason to be skeptical about the effectiveness of ignoring instructions when making a judgment. Authors point out that when evidence (that is, evident nonverbal cues) makes a significant impression on jurors, it is very difficult to eliminate the impact, even if they have been expressly instructed to please disregard a specific element. 

Empirical research shows that verbal cues are indeed more diagnostic for lying than nonverbal cues. Liars are generally less forthcoming, tell stories less convincingly and plausibly, and include fewer verifiable details. And therefore, people who rely more on these types of cues when making deception judgments outperform those who rely solely on nonverbal cues in accuracy. 

In addition, having training in what verbal behaviors we should pay attention to, is positively correlated with accuracy in lie detection. 

Thus, being instructed to pay attention to verbal cues is likely to result in increased accuracy in lie diagnosis. 

To test this, authors conducted three experiments that had more or less the same basis. Participants were asked to watch videos in which people were interviewed and told about events in their lives. Some of these stories were lies and others were true. The participants were divided into several groups, each with a condition: one group received no instructions at all, another group was instructed to ignore the nonverbal cues, and the last group was instructed to pay attention only to the verbal cues in addition to ignoring the nonverbal cues. 

The results show that giving instructions to ignore nonverbal cues is far from sufficient to prevent people from being influenced by them, and thus far from improving deception detection. 

In one of the three experiments it seems to have improved the latter point, however, not in a statistically significant way. 

Ignoring nonverbal cues seems to be a very complicated task, possibly because they play a vital role in everyday social interaction. This reliance on nonverbal cues is called visual bias.

It is suggested that future research should devote efforts to investigate this issue, as relying too much on nonverbal cues may lead us to make wrong decisions in diagnoses of truthfulness and deception, which, depending on the context, may go hand in hand with very negative consequences that, with research, could be prevented. 

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Friends of the Nonverbal Communication  Blog, this week we present the paper “Causal indicators for assessing the truthfulness of child speech in forensic interviews”, by Durante, Z.; Ardulov, V.; Kumar, M.; Gongola, J.; Lyon, T. and Narayanan, S. (2022), in which authors carry out a study to identify any factor that is relevant to discern between true and false declarations when it’s about forensic interviews to children. 

In other articles we have seen how interviews are carried out to obtain testimony in controlled settings when it comes to legal proceedings and investigations involving children who may have been victims or witnesses of a crime.

The child is in a stage of human life in which he/she is especially vulnerable, but, in addition, he/she can be influenced more easily, even trained or forced to admit or omit false information.

That is, the same developmental attributes that make children more vulnerable also make their testimony susceptible to manipulation.

To address these issues, legal experts have developed a basic framework for properly conducting interviews, which should be carried out by professionals trained in the field.

The process begins with relationship building, where innocent open questions predominate to help put the child at ease. Afterwards, the interviewer moves on to a somewhat more critical part, during which she obtains memories, directing questions, also open, towards the topic of interest.

Because of all that is at stake, legal experts and psychologists are dedicated to finding factors that indicate whether a child is prepared to disclose information and whether the information disclosed by the child is true or false.

A meta-analysis of studies conducted a few years ago demonstrates the ability of adults to detect children’s lies, with an overall accuracy rate of 54%, which only increased to 59% when trained people were asked. These are not very high percentages.

This is thought to happen because adults tend to have a bias towards believing that a child’s statement is always true.

The hypothesis underlying the authors’ study is that the way children adapt their behavior in response to an interviewer’s behavior, is a more informative sign of deception than the behavior itself.

To combat the difficulties in discerning between truth and deceit in an interview with children, the protocols are administered by a trained professional to obtain reliable testimonies. These interviews are designed to minimize secondary victimization and maximize the retrieval of valuable information without coercion or leading questions.

When that first contact is established, the interviewer asks about innocuous topics so that the child feels comfortable talking; then there will be questions that relate directly to the investigation, without pressuring the child to reveal specific details.

Deception detection studies have been largely limited to adult subjects, using video, audio, or text. Previous work in this area with children is usually done on linguistic characteristics of the interview.

Rather, this article uses acoustic features and considers the child’s coordination and behavior in terms of the interviewer’s, to better understand the child’s dynamics and personality in the interview.

To do this, approximately 200 interviews were conducted, each one with a child, conducted by two experienced interviewers.

The session begins with the child and one of the interviewers, in a room full of toys. The interviewer begins to engage with the child, but one of the toys breaks and a transgression happens. This interviewer tells the child that a different interviewer will come in to ask him/her some questions, and adds that he/she should not say anything about the broken toy to avoid getting into trouble.

The second interviewer follows the basic protocol, first building a relationship of trust with the child and then talking to him/her about the toy so that he/she tells him what has happened to it.

It seems that the best predictor of whether or not a child is telling the truth is his/her level of imagination. There is a very important relationship between children’s and interviewers’ use of vivid language that evokes clear mental images.

Children who plan to omit that an occurred transgression choose their language more carefully, severely that of the interviewer. Therefore, the child becomes more or less vague in his/her descriptions, depending on the level of specificity the interviewer is using.

In contrast, if a boy/girl is honest, he/she will not modify his/her behavior based on the interviewer’s discourse.

This relationship suggests that interview protocols require interviewers to modulate imaginative levels in their language, in order to more reliably track and differentiate between true and false testimonies.

In the future, dynamic systems models that incorporate the interaction of the speaker and the child’s behavior may provide more information and improve accuracy.

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Friends of the Nonverbal Communication Blog, this week we present the paper “Atypical behaviors found in some mental health conditions negatively affect judgements of deception and credibility” by Lim, A.; Young, R. L. and Brewer, N. (2022), in which authors carry out a study to examine some visible behaviors that we associate with an unbelievable speech, but also, are behaviors that people with some mental conditions can present. 

There is a general belief that what people say does not matter as much as their behavior when they say it, since it could indicate guilt, deception, regret…, etc.

In a 2006 study, 58 participants were asked when they knew someone was lying. The most common answers were: when there is an aversion to the gaze, incoherence, exaggerated body movements, certain facial expressions…

Only one of the elements was related to the content of the message: the inconsistency. Which leads us to think that we focus much more on non-verbal elements than on verbal ones, an idea consistent with numerous previous studies on the subject.

While the use of unreliable cues in lie detection is concerning in itself, it is likely to be problematic for people who have a disability or mental health condition as well.

For example, some people with social anxiety and social communication disorders have difficulty maintaining eye contact, which, rather than being a guilt avoidance mechanism, is more related to fear of social interaction.

On the other hand, repetitive body movements may be behaviors of people with neurodevelopmental disorders or autism spectrum disorders.

However, to an observer who doesn’t know much about the subject, these behaviors can be misinterpreted as signs of nervousness or guilt.

Another indicator of trustworthiness is emotional expressions. For example, there are studies that show that, in a trial, both victims and defendants are perceived as more credible when they show negative emotions (such as crying) rather than neutral (flat affect) or positive emotions (smiles).

Despite the fact that many studies have pointed out that it is necessary to pay attention to verbal signals especially, the stereotype that the most important are the non-verbal ones is very widespread, even for professionals such as police or judges.

This can be explained by attribution theory, which is based on the premise that individuals inherently seek to understand and explain observed behaviors, thus attributing a cause to the behavior.

In this study, authors examine the effect of four cues commonly associated with lying: gaze aversion, repetitive body movements, monologues, and flat affect. These behaviors are selected because they are associated with lying and also because they often appear in people with mental health problems.

It was hypothesized that individuals displaying these behaviors would be perceived as more liars and less credible.

The total sample was a total of 392 people of legal age, gathered through online tools.

They were shown a video of a game, in which one person had to choose whether or not to steal a small amount of money and then convince another person that they had or had not. If they got away with it, they got $50; if not, only 10$. The people in these videos were professional actors with a standardized script.

Results revealed significant effects of repetitive body movements and monologues on perceived deception, and significant effects of flat affect on credibility. It is important, as it could have important practical indications for people who often show these behaviors, for example, people with schizophrenia or mood disorders, people with neurodevelopmental disorders, autism spectrum, among others.

However, contrary to expectations, and also contrary to previous studies, gaze aversion did not have a significant effect on judgments of deception or credibility. It is possible that this happened because in this study this trait was studied individually, while in most studies it is interpreted within a context or accompanied by other behaviors that can give strength to the “lie effect”.

One limitation of the study is that it was not conducted with people with mental health conditions, so authors recommend the direct participation of these populations.

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Friends of the Nonverbal Communication Blog, this week we present the paper “Detecting deception using comparable truth baselines” by Bogaard, G.; Meijer, E. H.; Vrij, A. and Nahari, G. (2022), in which authors carry out a couple of experiments to know how the use of true base lines affects deception detection. 

We have already seen on several occasions throughout the different messages how the human capacity to detect lies is quite poor. Both the skill of laymen and the skill of professionals do not usually exceed the levels of luck.

Among the possible reasons that would explain the deficiency of these skills is the idea that people pay too much attention to behavioral signals, such as aversion to gaze and body movements. The reality is that there is not as much relationship as it is believed between these signs and deception.

Research has also shown that, in order to improve truth-lie detection accuracy, the observers should focus primarily on the content of people’s statements, as this has shown to be a more promising technique.

However, even verbal lie detection tools have a significant error rate, and one potential source of this error rate is individual differences in the verbal behavior of the liar; as meta-analytic research has shown.

That is, whether observers are able to detect a lie depends largely on the qualities of someone’s lying skills.

For example, fantasy-prone people are better at formulating believable lies, and people with verbal skills get away with it more often because they tend to include more detail in their false stories.

This is consistent with the finding that good liars report that they rely heavily on verbal strategies when lying.

One way to include the individual and verbal differences of liars in a lie detection procedure is through the baseline. That is, using a statement that is known to be true, or part of a statement that is also true, to compare between it and the lie.

The idea is that people are telling the truth during small talks, and any difference in behavior between this and the part of the interview that deals with the important issue being investigated is taken as a signal to pay attention to. attention and as a possible indicator of deception.

The problem is that this comparison is confusing. The topics covered in small talk are different from the ones being researched, and depending on the topic and personal relevance, people may respond differently. In addition, what is at stake contrasts substantially.

For this reason, there is the so-called “comparable truth baseline” (CTB). This baseline is used to be considered comparable to the research topic.

Previous studies have thrown up the idea that liars whose lies are accompanied by truth include more details. That is, good liars calibrate their deceptive responses against truthful information. Therefore, two contradictory ideas appear. On the one hand, if liars calibrate the amount of detail they report in their lie based on a previous truthful response, a CTB could decrease the discriminability between the lie and the truth. However, if the liars cannot gauge their responses, the use of a CTB has the potential to improve the discrimination between lying and truth.

That is why, in two different experiments, two aspects are investigated: first, if providing a CTB influences the detail of a subsequent statement provided by the same person; and second, if using a CTB statement would improve lie detection ability thanks to verbal cues.

In the first experiment 171 people participated; in the second, 138. In them, the participants were basically assigned the role of telling the truth or lying according to certain conditions, a process that is more explained in the original article, and then passing their complete statement through a tool used to evaluate the credibility of the speech , which is Reality Monitoring.

The analysis showed the existence of an interesting verbal pattern: the objective statements (the main ones and references to the research topics) of the truth tellers tend to include more temporal and auditory details than their reference statement, or their CTB, while the liars’ results showed the opposite pattern.

In the first of the experiments, no evidence appeared that the use of a CTB improves the accuracy when detecting truths and lies.

In experiment 2, those who used the CTB became worse at truth detection, but just as accurate at lie detection, compared to those who did not use the CTB.

However, authors mention that their results should be interpreted with caution, because their support is weak and it seems premature to use them as a reference. Therefore, they encourage other researchers to continue delving into this topic, plus, they leave the door open for future related experiments.

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Friends of the Nonverbal Communication Blog, this week we present the paper “Predicting Dishonesty When the Stakes are High: Physiologic Responses During Face-to-Face interactions identifies who Reneges on Promises to Cooperate”, by Zak, P. J.; Barraza, J. A.; Hu, X.; Zahedzadeh, G. and Murraya, J. (2022), in which the authors carry out an experiment where the subjects participate in a financial game, plus, they try to obtain evidence that there are some physiological changes that, according to previous literature, are produced in the body when one lies. 

We already know that communication and face-to-face interactions can influence the decisions we make, due to multiple non-verbal factors and even of a different nature that can activate stereotypes, such as gender, clothing, tattoos, attractiveness…

This is especially important in strategic and negotiation cases, where communication can increase each other’s understanding and strengthen cooperation, improving outcomes for both parties.

In addition, a very important fact is that the interactions prior to making decisions, the innocent or banal talks, also influence the strategic process. It is believed that, for the most part, they can increase cooperation.

Even so, we must take into account, in this era in which telematic meetings replace face-to-face meetings, that this influence of communication occurs much more easily in face-to-face meetings and not so much in remote meetings.

However, the opportunities to communicate also provide the opportunity to deceive and cheat. Deception and manipulation are the key of many strategic interactions, including military operations, negotiations, or even playing poker.

But there’s bad news for liars: concealment and distortion require extra cognitive effort. Deception involves several cognitive processes that are very costly, for example, the use of working memory and response inhibition. Physiological arousal, anxiety during communication, pupil dilation, among others, are signs associated with deception.

In addition, stress levels can be measured because the hormones associated with it increase their presence in the blood, so if lying causes stress, it could be found out when it is happening by observing the level of these hormones in our body.

From an evolutionary perspective, it is believed that creatures that live in groups, such as humans, have had to develop physiological mechanisms to identify individuals that are likely to cooperate with the group or not.

Some of these mechanisms may be consciously recognizable, such as the Duchenne smile. Others are only perceived unconsciously.

Authors’ intentions with this study were to assess the trust between adults who communicate face to face before participating in a game where, in pairs, and if they cooperate, they can win a significant amount of money.

75 subjects participated in the experiment. They had to participate in the so-called “trust game”. In it, software assigned pairs and a role to each of the two people in each pair. Player 1 had to transfer an amount of money to player 2, which would come from his own reserve. What was transferred to player 2 would be multiplied by a certain value. Player 2 would be notified of the amount received and should return to player 1 one quantity that would not be multiplied. If the cooperation between the two of them was good, he could earn up to $500.

Experts point out that the transfer from player 1 to player 2 measures trust, while the transfer from player 2 to player 1 measures trustworthiness.

However, the most interesting thing about this experiment is that the players had a chat for a couple of minutes before participating in the game. They were told that they could discuss a strategy to follow between them, although it was not mandatory.

The results obtained suggested that, although almost all the conversations between the pairs of the game resulted in a cooperative commitment, approximately one third of the players did not keep their promises. The initial hypothesis that researchers had was that high levels of stress hormones would be observed in those who lied. By measuring hormone levels before and after the interaction, it was seen how those who had lied had an increase in this type of hormone in their blood.

Additionally, when players lied, they reported, in post-game self-reports, increased negative emotions, revealing the psychological cost of cheating.

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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.

If you want to know more about nonverbal behavior and how it influences our personal relationships, visit our Nonverbal Communication Certificate, a 100% online program certificated by the Heritage University (Washington) with special discounts for readers of the Nonverbal Communication Blog. 

Friends of the Nonverbal Communication Blog, this week we present the paper “Gender affects body language Reading” de Sokolov, A. A.; Krüger, S.; Enck, S.; Krägeloh-Mann, I. y Pavlova, M. A. (2012), they carried out one of the first studies about the different abilities of men and women to understand nonverbal language.

Reading body language has an immense importance when it comes about adaptive social behavior and communication in general. This skill is part of the core of social competences.

Those people who can infer emotions in others, represented by body movements, are likely to be more successful in interacting with other people.

In addition, it is possible to discriminate between deception and truth by observing the body and all the nonverbal information that the person transmits to us, considering it as a whole and analyzing its consistency.

The dynamic body expressions, gestures and actions of others are a very rich and valid source to pay attention to in our social interactions.

It is known from previous literature that emotions expressed by dynamic bodies, compared to faces, elicit greater activation in several areas of the brain, including the superior temporal sulcus, which is critically important in the social brain.

But how do you know who to trust? These judgments are vital to social interaction, and it appears that men and women differ in the cues they pay attention to.

According to generalized beliefs, women show greater sensitivity to nonverbal signals: they better discriminate friendship from sexual interest and are more competent in recognizing emotions on the face. Even women with Asperger’s syndrome would better recognize the emotions of dynamic faces than men.

In addition, women tend to recognize emotions better from faces than from voices, while men show the opposite trend.

Surprisingly, however, the impact of gender on reading body language is largely unknown. In a study carried out in the early 1980s, the superiority of women in reading it was pointed out, but there is not much more literature on the matter, as there is with other aspects of nonverbal communication.

The article tries to fill the gap and clarify whether the gender of the perceiver affects the recognition of emotional expressions conveyed by the actions of others and, if so, how it does. More specifically, authors ask whether gender affects the recognition of emotions represented by body movement, or, in other words, whether females excel at recognizing emotional actions.

To this end, authors gathered 34 healthy adults between the ages of 20 and 36 who were enrolled in the study.

Authors used light dot screens depicting a person knocking on the door with different emotional expressions (happy, neutral, or angry) and showed this to the subjects. They had to infer which was the emotion of the person in that moment.

The light spot technique was used because it helps to isolate the information revealed by the appearance of other signals. The perceivers saw only a few bright spots placed on the joints of an arm, that, otherwise, would be completely invisible.

The results yielded interesting information. It seems that the effect of gender would be related to the emotional content of the actions.

Women tend to excel at recognizing angry actions, while men excel at recognizing the happy ones.

Additionally, females outperform males in recognizing emotionally neutral hits.

Women have been socially associated with a high sensitivity to emotional cues and subtle details; the reverse occurring with men, who may have a better performance in recognizing negative threatening expressions.

These assumptions are based on the different evolutionary and sociocultural roles of both genders.

The data is consistent with findings showing that men appear to exhibit stronger brain activation in response to positive images (depicting landscapes, sports activities, families, or erotic scenes) than women.

Finally, women have an advantage in recognizing neutral movements. It suggests that they are better attuned to the lack of emotional content in bodily actions.

Authors point out that future research should be directed at uncovering sex differences in brain activity during body language reading. Such research would also shed light on sex differences in neuropsychiatric conditions characterized by deficits in social cognition, such as autism spectrum disorders, depression, or schizophrenia.

If you want to know more about nonverbal behavior and how it influences our personal relationships, visit our Nonverbal Communication Certificate, a 100% online program certificated by the Heritage University (Washington) with special discounts for readers of the Nonverbal Communication Blog. 

Friends of the Nonverbal Communication Blog, this week we present the paper “The Limits of Conscious
Deception Detection: When Reliance on False Deception Cues Contributes to Inaccurate Judgements”,
by Stel, M.; Schwarz, A.; van Dijk, E. and van Knippenberg, A. (2020),in which authors explore the ideas
of unconscious thought, fake cues of deception and people’s ability to detect lies.

We have already seen in several articles how the ability to deception detection, in addition to being one of the most interesting fields in the study of non-verbal language, is an extremely important and practical skill in everyday life.

However, it is important to remember that most studies show that the level of this ability does not usually exceed the level of probability.

One of the arguments used to explain this is that people have a tendency to believe in the information that is presented to them. This is called the truth bias or the “default value of truth.” Since most communications are honest most of the time, the benefits of believing are higher than the costs of the occasional deception. Therefore, it is understood that people can detect truths with greater precision than lies.

So, if overconfidence gets in the way of a successful deception detection, wouldn’t mistrust be an antidote to it?

In this article, authors investigate whether people’s ability to detect deception varies depending on whether or not they feel mistrust.

Previous research shows that increasing suspicion would decrease truth bias. However, studies about the effects of suspicion on the accuracy of deception detection offer mixed results: some are positive and others negative.

But only a few studies on deception detection focused on the effects of mistrust instead of suspicion. They are similar concepts, but different. In a state of suspicion, the perceivers are not sure of the motivations of the others; while in a state of mistrust, negative expectations about these motivations are added. As a result, suspicious perceivers are more willing to seek information to determine whether or not someone else’s motivations are honest. On the other hand, mistrust affects the perceiver’s need to face a possibly threatening situation. By having different effects, they are likely to affect deception detection abilities differently as well.

According to some experts, distrust indicates that the environment is not the usual and, as a result, people avoid routine strategies, and examine deeply more people’s behavior. This encourages deliberate conscious processing, whereas when we have signals that a situation is safe, less effort cognitive processing is encouraged.

In other words, it is suggested that a state of mistrust would promote the conscious processing of information, while a state of trust would promote intuitive or unconscious processing. Decisions for both thought forms have differences: for unconscious thinking decisions, attention is directed elsewhere before making them; for conscious or automatic decisions, the decision is made immediately. All this makes these ideas attractive to authors and they decide to explore them.

Other findings suggest that conscious processes may hamper the ability to detect deception. Judging whether a person is truthful or deceiving us, can be a complex decision to make. First, we evaluate the signals, such as the level of detail, the plausibility of the story …, and this is cognitively demanding. Second, we must process verbal and nonverbal content, and pay attention to different types of observable cues. Because judging whether a person is telling the truth or not is a demanding process, the theory of unconscious thought suggests that the detection of deception can be better handled with it, since it is assumed that the unconscious thought would have more processing power.

Research focused directly on conscious and unconscious thinking showed that people’s ability to detect deception increased when they were prevented from consciously deliberating on the information presented.

For the experiment carried out, authors used covert manipulation, causing observers to adopt facial expressions of distrust (narrowed eyes) or confidence (wide eyes). The aim was to induce these states of mind, based on previous studies.

A total of 93 university students participated and watched eight video clips showing a person lying or telling the truth. The participants were then asked how much they trusted this person, requiring a score on a scale to measure this aspect.

A second study was conducted that investigated whether confidence in the use of false indicators of deception influenced mistrust in detection. 54 people participated in it. The experiment was similar to the first one, but the participants had to explain why they trusted or mistrusted the people in the videos.

Although increasing mistrust was expected to reduce the truth bias, the results did not show that distrustful people were less likely to mistake a lie for a truth. On the contrary, it happened that mistrust led the participants to confuse truths with lies.

That is, mistrust led participants to misjudge those who told the truth as liars. Furthermore, with study 2, it was shown that distrustful people relied more on false beliefs about lying when judging truth-tellers than when judging liars.

Although the existence or not of benefits in unconscious deception judgments was finally not directly proven, authors showed that contextually induced modes of thought affect the ability to detect deception, when confidence or mistrust was induced in the subjects.

One limitation is that the sample in Study 2 is quite small, and as such, the results should be interpreted with caution.

In conclusion, authors showed that contextual mistrust difficulties people’s ability to detect deception, especially for those who tell the truth, who are often judged as liars.

If you want to know more about nonverbal behavior and how it influences our personal relationships, visit our Nonverbal Communication Certificate, a 100% online program certificated by the Heritage University (Washington) with special discounts for readers of the Nonverbal Communication Blog.

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