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.

If you want to know more about nonverbal behavior and how it affects personal relationships, visit our Master of Science in Nonverbal and Deceptive Behavior, which you can take in English or Spanish, with special grants for readers of the Nonverbal Communication Blog.

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. 

If you want to know more about nonverbal behavior and how it affects personal relationships, visit our Master of Science in Nonverbal and Deceptive Behavior, which you can take in English or Spanish, with special grants for readers of the Nonverbal Communication Blog.

Friends of the Nonverbal Communication Blog, this week we present the paper “Effectiveness, Attractiveness, and Emotional Response to Voice Pitch and Hand Gestures in Public Speaking”, by Rodero, E. (2022), in which the author carries out a study to know how the variations in the tone of voice intensity, and the frequency and exaggeration of hand gestures influence the effectiveness of public speeches.

When we see and hear a person speaking, we can distinguish two distinct parts of the communication that are very important: what the person says and how he or she says it, that is, the content and the form of the message. Or, in other words, verbal and nonverbal communication, both equally important. 

The author decides to focus, in this case, on nonverbal communication, since every part of our body, every movement, facial expression or variation of tone, has a meaning. In fact, our brain can create an impression about a person giving a speech in just milliseconds, just by looking at his/her face, his/her body, or listening to his/her voice. 

We have already mentioned on numerous occasions that there are different channels of nonverbal communication. On the one hand, we have everything related to kinesics, such as gestures, postures or movement; there is also paralanguage, which are the features of the voice; proxemics, which refers to space and distance management; the appearance of people, such as clothing, jewelry, even skin color. 

Nonverbal communication signals can influence perception and message processing. We use our body and voice changes to reinforce or qualify what we say, convey emotions, attitudes, intentions, regulate the flow of communication….

According to experts, charismatic leaders use variations in tone of voice, eye contact, gestures and facial expressions to differentiate themselves from the rest. The way television presenters, for example, use their voices and gestures when speaking in public is crucial to engage the audience, attract their attention and provoke emotions. 

This research analyzes the effectiveness, appeal and emotional response of different strategies related to tone of voice and hand gestures in public speeches. But why these two elements?

First of all, voice plays a very important role in our social relationships, and therefore in persuasive messages, such as public speeches. How we use our voice is called prosody, and it represents the set of characteristics we use when speaking. 

One of the most important components of prosody is intonation, yet research on the influence of intonation variations when it comes to public speaking is scarce, despite its importance. 

In 2011, a study found that substantial changes in pitch increased persuasiveness and credibility, and in 2021 it was concluded that a higher and more varied pitch in the voice is related to greater charisma. In public speeches, a moderate emphatic intonation is considered the most effective, captures more attention and provokes greater excitement, improving comprehension, due to its dynamism. 

However, although these changes are very positive, excessive variations could be counterproductive and make the speech exaggerated and unnatural, so the author’s hypothesis is that the moderate strategy would be the best option. 

On the other hand, we have hand gestures. According to experts, people who use hand gestures are perceived as more effective, persuasive, credible, dominant, outgoing, sociable and honest. Therefore, there is a tendency to associate positive traits with hand movements. 

A study conducted with TED talks concluded that hand gestures make the speaker appear more convincing. However, as with the tone of voice, too much intensity could be overdone and cause distractions. 

For the study, a total of 48 videos of short speeches were recorded in which three variations of voice pitch (soft, moderate, intense) and three intensities of hand gestures (soft, moderate, intense) were combined. 120 university students formed the study sample. 

The findings showed that the nonverbal communication cues examined were relevant in determining the effectiveness and attractiveness of a public speech.

The strategy with moderate pitch variations, in terms of tone of voice, was the most effective and attractive, followed by the high variation style and, in third place, few variations. The result is in line with the findings of previous studies.

A balanced strategy with tone changes, neither too few nor too many, is perceived as more dynamic and therefore more effective, since a more expressive voice is always perceived better than a dull voice, and brings charisma. 

As for gestures, it was exactly the same. The moderate strategy was the most successful, followed by the strategy of many gestures and, in last position, few gestures. 

By combining strategies related to voice tone and gestures, the author obtained the novel finding that, when the voice uses moderate variations in tone, both moderate gestures and exaggerated gestures are effective. 

The results of this study allow us to advance in the analysis of nonverbal cues, especially, as is logical, in the study of voice tone and gestures. The author points out the need to devote greater efforts to studying the effects of both channels combined, which, as we have seen, can offer promising answers to interesting questions. 

If you want to know more about nonverbal behavior and how it affects personal relationships, visit our Master of Science in Nonverbal and Deceptive Behavior, which you can take in English or Spanish, with special grants for readers of the Nonverbal Communication Blog.

Friends of the Nonverbal Communication Club, this week we present the paper “Intrapersonal Behavioral Coordination and Expressive Accuracy During First Impressions” by Latif, N.; Human, L. J.; Capozzi, F. and Ristic, J. (2021). In this article the authors examine whether expressive accuracy is related to the variability in the coordination between a person’s head and body movements.

If there’s something that worry us in social interaction is, without doubts, the first impression. How do others perceive us? Are we transmitting how we really are or, on the contrary, a wrong image altered by being nervous?

During the history of the nonverbal behavior, numerous aspects have been studied in order to understand other people’s personalities attending to how they express theirselves. For instance, and as we already know, much attention has been paid to facial expressions, gestures, or body movements.

What’s new about this study is the authors choose a very specific aspect (variability in the coordination between a person’s head and body movements) and try to find a nexus between it and how accurately people perceive our personality in first impressions.

But why this topic?

Simply because head and body movements play a very special role in social communication. As an example: we use them to transmit interest in a conversation, to show we are listening or paying attention, maybe that we want to go…

Due to the importance of these movements, and to the interest in writing an article about a very specific aspect of human behavior, authors decided to investigate whether expressive accuracy, and how others perceive our personality, is related to the variability in the coordination between a person’s head and body movements.

In order to that, they made an experiment which consisted in recruit, on one hand, 105 volunteers, at least 18 years of age (the observed group) and, on the other hand, 94 (the observer group).

The observed group completed an initial personality questionnaire, plus, family or friends of each individual were asked about their personalities to contrast the information and consolidate a personality profile. In addition to that, each one of the members of the observed group completed a video-recorded interview, so the other group could examinate their nonverbal behavior.

The observer group watched the interview and answered the personality questionnaire for each volunteer of the other group.

The results were clear: people that, during the interview showed a great variability in coordination between head and body movements, were perceived (according to the personality profile obtained at the beginning of the experiment) more accurately than the ones with a low variability.

Plus, a correlation between expressing a higher variability and being perceived as socially skilled was observed.

Other important data obtained in the study, is that these movements’ variability seems to have a relation with personality traits that are easily to observe, such as if we are extroverted, energetic or nice to others. It happens the other way round if we are talking about personality traits hard to observe, for instance being depressed or blue: this seems to have less relation.

It’s important to mention that, when variability in head and body movements’ coordination is low, looks like others don’t detect our personality so easily.

But, why does variability in head and body movements’ coordination seem to promote expressive accuracy?

Chiefly, is possible that, when this variability is high, it’s easier for us to shed clues to others about our personality. If we move our head and hands when we’re talking about something, and then somebody changes the topic and we stop moving and freeze, the person we’re talking to is eager to think that the first subject was more important to us than the second. We’re giving clues to our listener.

Secondly, variability in coordination of these movements affects to our interlocutor’s attention. Namely, these changes keep the person listening to us, watching our faces, our body, our gestures. The opposite happens when the variability is low. Thus, when variability is high, the person we’re talking to would catch more easily our personality traits, just because pays more attention to us.

Despite the results of the study and its conclusions are solid, authors mention the necessity of keeping delving into the subject, of obtaining corrections, to get more accurate answers to such complex issues.

NonVerbal Communication Blog