Do Dynamic Compared to Static Facial Expressions of Happiness and Anger Reveal Enhanced Facial Mimicry?

Face your fears: direct and indirect measurement of responses to looming threats

This study investigated the emotional and behavioural effects of looming threats using both recalled (self-reported valence) and real-time response measurements (facial expressions). The looming bias refers to the tendency to underestimate the time of arrival of rapidly approaching (looming) stimuli, providing additional time for defensive reactions. While previous research has shown negative emotional responses to looming threats based on self-reports after stimulus exposure, facial expressions offer valuable insights into emotional experiences and non-verbal behaviour during stimulus exposure. A face reading experiment examined responses to threats in motion, considering stimulus direction (looming versus receding motion) and threat strength (more versus less threatening stimuli). We also explored the added value of facial expression recognition compared to self-reported valence. Results indicated that looming threats elicit more negative facial expressions than receding threats, supporting previous findings on the looming bias. Further, more (vs. less) threatening stimuli evoked more negative facial expressions, but only when the threats were looming rather than receding. Interestingly, facial expressions of valence and self-reported valence showed opposing results, suggesting the importance of incorporating facial expression recognition to understand defensive responses to looming threats more comprehensively.

Influence of child and adult faces with face masks on emotion perception and facial mimicry

Emotional mimicry, the imitation of others' emotion expressions, is related to increased interpersonal closeness and better interaction quality. Yet, little research has focused on the effect of face masks on emotional mimicry and none on (masked) child faces. To address this gap, we conducted an online experiment (N = 235, German sample, adult perceivers). Masks reduced emotion recognition accuracy for all expressions, except in the case of anger in masked child faces, where perceived anger was even increased. Perceived interpersonal closeness was reduced for masked happy and sad faces. For both child and adult expressers, masks reduced facial mimicry of happy expressions, with no mask effects for sadness and anger expression. A stronger mask effect on facial happiness mimicry of child faces was mediated by the degree of emotion recognition accuracy. Smiles shown by masked children were not recognized well, likely due to the absence of wrinkles around the eyes in child faces. Independent of masks, sadness shown by children was mimicked even more strongly than when shown by adults. These results provide evidence for facial mimicry of child expressions by adult perceivers and show that the effects of face masks on emotion communication may vary when children wear them.

Effects of positive and negative social feedback on motivation, evaluative learning, and socio-emotional processing

Social rewards and punishments are strong motivators. Since experimental work has focused on young adults using simplistic feedback, the effects of more naturalistic stimuli on motivation, evaluative learning, and socio-emotional processing with advanced age remain unclear. Therefore, we compared the effects of static (photos) vs dynamic (videos) social feedback in a social incentive delay (SID) task in young (18-35 years) and older adults (50-84 years) with neutral, positive, and negative feedback, on response times (RTs), and assessed the emotional valence of feedback cues and feedback videos. We found that anticipating positive and negative social feedback accelerated RTs regardless of age and without additional effects of video feedback. Furthermore, the results suggest a valence transfer from positive feedback videos to predictive cues in both groups (i.e., evaluative learning). Finally, older adults reported less pronounced negative affect for negative feedback videos, indicating age differences in socio-emotional processing. As such, our findings foster our understanding of the underlying cognitive and emotional aspects involved in the processing of social rewards and punishments.

The "zipper model of empathy" applied to violence in schizophrenia: A search for social cognitive underpinnings of lack of empathic behavior

BACKGROUND

The "zipper model of empathy" has been proposed for psychopathy. It postulates that empathic behavior may fail to arise due to impaired facial emotion recognition. In this study, we examined if the model may be of relevance for schizophrenia.

METHODS

In a sample of participants with schizophrenia and a history of severe interpersonal violence, associations between measures of social cognition (emotion recognition, theory of mind) and aspects of psychopathy (lack of empathy, lack of remorse) were investigated. A non-violent sample experiencing schizophrenia served as a control group.

RESULTS

Correlation analyses revealed a specific and statistically significant association between facial emotion recognition and lack of empathy in the violent sample. Follow-up analyses identified that neutral emotions were of particular importance. Logistic regression analyses confirmed that impairments in facial emotion recognition predicted levels of empathy in the violent sample experiencing schizophrenia.

CONCLUSIONS

Our results suggest that the "zipper model of empathy" may be relevant for schizophrenia. The findings further point to the potential benefit of including social cognitive training in the treatment of persons with schizophrenia and a history of interpersonal aggression.

Facial mimicry and metacognitive judgments in emotion recognition are distinctly modulated by social anxiety and autistic traits

Facial mimicry as well as the accurate assessment of one's performance when judging others' emotional expressions have been suggested to inform successful emotion recognition. Differences in the integration of these two information sources might explain alterations in the perception of others' emotions in individuals with Social Anxiety Disorder and individuals on the autism spectrum. Using a non-clinical sample (N = 57), we examined the role of social anxiety and autistic traits in the link between facial mimicry, or confidence in one's performance, and emotion recognition. While participants were presented with videos of spontaneous emotional facial expressions, we measured their facial muscle activity, asked them to label the expressions and indicate their confidence in accurately labelling the expressions. Our results showed that confidence in emotion recognition was lower with higher social anxiety traits even though actual recognition was not related to social anxiety traits. Higher autistic traits, in contrast, were associated with worse recognition, and a weakened link between facial mimicry and performance. Consequently, high social anxiety traits might not affect emotion recognition itself, but the top-down evaluation of own abilities in emotion recognition contexts. High autistic traits, in contrast, may be related to lower integration of sensorimotor simulations, which promote emotion recognition.

Visual perception of emotion cues in dogs: a critical review of methodologies

Comparative studies of human-dog cognition have grown exponentially since the 2000's, but the focus on how dogs look at us (as well as other dogs) as social partners is a more recent phenomenon despite its importance to human-dog interactions. Here, we briefly summarise the current state of research in visual perception of emotion cues in dogs and why this area is important; we then critically review its most commonly used methods, by discussing conceptual and methodological challenges and associated limitations in depth; finally, we suggest some possible solutions and recommend best practice for future research. Typically, most studies in this field have concentrated on facial emotional cues, with full body information rarely considered. There are many challenges in the way studies are conceptually designed (e.g., use of non-naturalistic stimuli) and the way researchers incorporate biases (e.g., anthropomorphism) into experimental designs, which may lead to problematic conclusions. However, technological and scientific advances offer the opportunity to gather much more valid, objective, and systematic data in this rapidly expanding field of study. Solving conceptual and methodological challenges in the field of emotion perception research in dogs will not only be beneficial in improving research in dog-human interactions, but also within the comparative psychology area, in which dogs are an important model species to study evolutionary processes.

What is missing in the study of emotion expression?

While approaching celebrations for the 150 years of "The Expression of the Emotions in Man and Animals", scientists' conclusions on emotion expression are still debated. Emotion expression has been traditionally anchored to prototypical and mutually exclusive facial expressions (e.g., anger, disgust, fear, happiness, sadness, and surprise). However, people express emotions in nuanced patterns and - crucially - not everything is in the face. In recent decades considerable work has critiqued this classical view, calling for a more fluid and flexible approach that considers how humans dynamically perform genuine expressions with their bodies in context. A growing body of evidence suggests that each emotional display is a complex, multi-component, motoric event. The human face is never static, but continuously acts and reacts to internal and environmental stimuli, with the coordinated action of muscles throughout the body. Moreover, two anatomically and functionally different neural pathways sub-serve voluntary and involuntary expressions. An interesting implication is that we have distinct and independent pathways for genuine and posed facial expressions, and different combinations may occur across the vertical facial axis. Investigating the time course of these facial blends, which can be controlled consciously only in part, is recently providing a useful operational test for comparing the different predictions of various models on the lateralization of emotions. This concise review will identify shortcomings and new challenges regarding the study of emotion expressions at face, body, and contextual levels, eventually resulting in a theoretical and methodological shift in the study of emotions. We contend that the most feasible solution to address the complex world of emotion expression is defining a completely new and more complete approach to emotional investigation. This approach can potentially lead us to the roots of emotional display, and to the individual mechanisms underlying their expression (i.e., individual emotional signatures).

An examination of autonomic and facial responses to prototypical facial emotion expressions in psychopathy

Meta-analyses have found that people high in psychopathy categorize (or “recognize”) others’ prototypical facial emotion expressions with reduced accuracy. However, these have been contested with remaining questions regarding the strength, specificity, and mechanisms of this ability in psychopathy. In addition, few studies have tested holistically whether psychopathy is related to reduced facial mimicry or autonomic arousal in response to others’ dynamic facial expressions. Therefore, the current study presented 6 s videos of a target person making prototypical emotion expressions (anger, fear, disgust, sadness, joy, and neutral) to N = 88 incarcerated adult males while recording facial electromyography, skin conductance response (SCR), and heart rate. Participants identified the emotion category and rated the valence and intensity of the target person’s emotion. Psychopathy was assessed via the Psychopathy Checklist-Revised (PCL-R). We predicted that overall PCL-R scores and scores for the interpersonal/affective traits, in particular, would be related to reduced emotion categorization accuracy, valence ratings, intensity ratings, facial mimicry, SCR amplitude, and cardiac deceleration in response to the prototypical facial emotion expressions. In contrast to our hypotheses, PCL-R scores were unrelated to emotion categorization accuracy, valence ratings, and intensity ratings. Stimuli failed to elicit facial mimicry from the full sample, which does not allow drawing conclusions about the relationship between psychopathy and facial mimicry. However, participants displayed general autonomic arousal responses, but not to prototypical emotion expressions per se. PCL-R scores were also unrelated to SCR and cardiac deceleration. These findings failed to identify aberrant behavioral and physiological responses to prototypical facial emotion expressions in relation to psychopathy.

Reading Your Emotions in My Physiology? Reliable Emotion Interpretations in Absence of a Robust Physiological Resonance

Affective states are expressed in an individual’s physical appearance, ranging from facial expressions and body postures, to indicators of physiological arousal (e.g., a blush). Confirming the claimed communicative function of these markers, humans are capable of distinguishing between a variety of discrete emotion displays. In an attempt to explain the underlying mechanism, characteristic bodily changes within the observer, including physiological arousal and mimicry, have been suggested to facilitate the interpretation of an expression. The current study aims to create a holistic picture of emotion perception by (1) using three different sources of emotional information (prototypical facial expressions, bodily expressions, and subtle facial cues) and (2) measuring changes in multiple physiological signals (facial electromyography, skin conductance level, skin temperature, and pupil size). While participants clearly discriminated between perceived emotional expressions, there was no overall 1–1 correspondence with their physiological responses. Some specific but robust effects were observed. Angry facial expressions were consistently responded to with a peak in skin conductance level. Furthermore, sad body expressions were associated with a drop in skin temperature. In addition to being the best recognized expression, viewing happy faces elicited congruent facial muscle responses, which supports the potential role of embodied simulation in emotion recognition. Lastly, tears were not only rated as highly emotional intense but also evoked a peak in skin conductance level in the observer. The absence of distinct physiological responses to other expressions could be explained by the lacking functionality of affect sharing in a non-interactive experimental context. Consequentially, emotional alignment in body and mind might especially take place in real social situations, which should be considered in future research.

Empathy for pain in individuals with autistic traits during observation of static and dynamic stimuli

Previous studies have reported that individuals with autistic traits, like those with Autism Spectrum Disorder (ASD), may have impaired empathic responses when observing static stimuli of others' pain. However, it remains unclear whether individuals with autistic traits exhibit impaired empathy for pain in response to dynamic stimuli. The present study addressed this question by recruiting 529 individuals whose autistic traits were assessed using the autism-spectrum quotient (AQ) questionnaire. Thirty participants who scored within the top 10% and bottom 10% on the AQ were selected into High-AQ and Low-AQ groups, respectively. This study employed painful whole-body action pictures and videos as static and dynamic stimuli. Both groups were instructed to judge whether the models in the stimuli were experiencing pain, and their reaction times, accuracy and event-related potential (ERP) data were recorded. Results showed that the P2 amplitudes were larger in the High-AQ group than in the Low-AQ group when viewing painful static stimuli, while no difference between the two groups was found when viewing painful dynamic stimuli. These results suggest that autistic traits influenced the emotional processing of others' pain in response to static stimuli.

Feelings first? Sex differences in affective and cognitive processes in emotion recognition

The recognition of emotional expressions is important for social understanding and interaction, but findings on the relationship between emotion recognition, empathy, and theory of mind, as well as sex differences in these relationships, have been inconsistent. This may reflect the relative involvement of affective and cognitive processes at different stages of emotion recognition and in different experimental paradigms. In this study, images of faces were morphed from neutral to full expression of five basic emotions (anger, disgust, fear, happiness, and sadness), which participants were asked to identify as quickly and accurately as possible. Accuracy and response times from healthy males (n = 46) and females (n = 43) were analysed in relation to self-reported empathy (Empathy Quotient; EQ) and mentalising/theory of mind (Reading the Mind in the Eyes Test). Females were faster and more accurate than males in recognising dynamic emotions. Linear mixed-effects modelling showed that response times were inversely related to the emotional empathy subscale of the EQ, but this was accounted for by a female advantage on both measures. Accuracy was unrelated to EQ scores but was predicted independently by sex and Eyes Test scores. These findings suggest that rapid processing of dynamic emotional expressions is strongly influenced by sex, which may reflect the greater involvement of affective processes at earlier stages of emotion recognition.

Light makeup decreases receivers' negative emotional experience

Makeup is widely used in modern society and has a positive effect on perceived attractiveness. However, little is known about the other possible outcomes of makeup use. In this study, we investigated whether makeup enhances a receiver's emotional experience. Dynamic faces with or without makeup are presented in Experiments 1 and 2. Participants were asked to imagine themselves video chatting with a target person (expresser) with different expressions: neutral, angry, sad, or happy, and then to appraise their own subjective emotional experience. Emotional valence, arousal, and willingness to communicate were also assessed in Experiment 2. The results showed that makeup improved perceived facial attractiveness and increased the willingness to communicate. More importantly, it revealed that wearing makeup could weaken receivers' negative experiences arising from the angry and sad conditions, which is not the case for the non-makeup condition, but could not affect the happy contagion. Furthermore, incremental changes in the amount of makeup were not accompanied by incremental changes in emotional appraisal (valence and arousal). Overall, we found that makeup may affect emotional contagion and interpersonal communication. Whether the alleviated negative experience due to makeup is adaptive may need further discussion.

Creation and validation of the Picture-Set of Young Children's Affective Facial Expressions (PSYCAFE)

The immediate detection and correct processing of affective facial expressions are one of the most important competences in social interaction and thus a main subject in emotion and affect research. Generally, studies in these research domains, use pictures of adults who display affective facial expressions as experimental stimuli. However, for studies investigating developmental psychology and attachment behaviour it is necessary to use age-matched stimuli, where it is children that display affective expressions. PSYCAFE represents a newly developed picture-set of children’s faces. It includes reference portraits of girls and boys aged 4 to 6 years averaged digitally from different individual pictures, that were categorized to six basic affects (fear, disgust, happiness, sadness, anger and surprise) plus a neutral facial expression by cluster analysis. This procedure led to deindividualized and affect prototypical portraits. Individual affect expressive portraits of adults from an already validated picture-set (KDEF) were used in a similar way to create affect prototypical images also of adults. The stimulus set has been validated on human observers and entail emotion recognition accuracy rates and scores for intensity, authenticity and likeability ratings of the specific affect displayed. Moreover, the stimuli have also been characterized by the iMotions Facial Expression Analysis Module, providing additional data on probability values representing the likelihood that the stimuli depict the expected affect. Finally, the validation data from human observers and iMotions are compared to data on facial mimicry of healthy adults in response to these portraits, measured by facial EMG (m. zygomaticus major and m. corrugator supercilii).

Alexithymia and Facial Mimicry in Response to Infant and Adult Affect-Expressive Faces

Facial mimicry is the automatic tendency to imitate facial expressions of emotions. Alexithymia is associated with a reduced facial mimicry ability to affect expressions of adults. There is evidence that the baby schema may influence this process. In this study it was tested experimentally whether facial mimicry of the alexithymic group (AG) is different from the control group (CG) in response to dynamic facial affect expressions of children and adults. A multi-method approach (20-point Toronto Alexithymia Scale and Toronto Structured Interview for Alexithymia) was used for assessing levels of alexithymia. From 3503 initial data sets, two groups of 38 high and low alexithymic individuals without relevant mental or physical diseases were matched regarding age, gender, and education. Facial mimicry was induced by presentation of naturalistic affect-expressive video sequences (fear, sadness, disgust, anger, and joy) taken from validated sets of faces from adults (Averaged Karolinska Directed Emotional Faces) and children (Picture-Set of Young Children's Affective Facial Expressions). The videos started with a neutral face and reached maximum affect expression within 2 s. The responses of the groups were measured by facial electromyographic activity (fEMG) of corrugator supercilii and zygomaticus major muscles. Differences in fEMG response (4000 ms) were tested in a variance analytical model. There was one significant main effect for the factor emotion and four interaction effects for the factors group × age, muscle × age, muscle × emotion, and for the triple interaction muscle × age × emotion. The participants of AG showed a decreased fEMG activity in response to the presented faces of adults compared to the CG but not for the faces of children. The affect-expressive faces of children induced enhanced zygomatic and reduced corrugator muscle activity in both groups. Despite existing deficits in the facial mimicry of alexithymic persons, affect-expressive faces of children seem to trigger a stronger positive emotional involvement even in the AG.

Levels of naturalism in social neuroscience research

In order to understand ecologically meaningful social behaviors and their neural substrates in humans and other animals, researchers have been using a variety of social stimuli in the laboratory with a goal of extracting specific processes in real-life scenarios. However, certain stimuli may not be sufficiently effective at evoking typical social behaviors and neural responses. Here, we review empirical research employing different types of social stimuli by classifying them into five levels of naturalism. We describe the advantages and limitations while providing selected example studies for each level. We emphasize the important trade-off between experimental control and ecological validity across the five levels of naturalism. Taking advantage of newly emerging tools, such as real-time videos, virtual avatars, and wireless neural sampling techniques, researchers are now more than ever able to adopt social stimuli at a higher level of naturalism to better capture the dynamics and contingency of real-life social interaction.

Social exclusion enhances affiliative signaling

Reciprocating smiles is important for maintaining social bonds as it both signals affiliative intent and elicits affiliative responses. Feelings of social exclusion may increase mimicry as a means to regulate affiliative bonds with others. In this study, we examined whether feelings of exclusion lead people to selectively reciprocate the facial expressions of more affiliative-looking people. Participants first wrote about either a time they were excluded or a neutral event. They then classified 20 smiles-half spontaneous smiles and half posed. Facial electromyography recorded smile muscle activity. Excluded participants distinguished the two smile types better than controls. Excluded participants also showed greater zygomaticus major (mouth smiling) activity toward enjoyment smiles compared to posed smiles; control participants did not. Orbicularis oculi (eye crinkle) activity matched that of the smile type viewed, but did not vary by exclusion condition. Affiliative social regulation is discussed as a possible explanation for these effects.

Relating self-other overlap to ingroup bias in emotional mimicry

Humans tend to show congruent facial expressions automatically in reaction to their partners which is defined as emotional mimicry. Although occurring unconsciously, this tendency has been proven to be modulated by social contextual factors such as group membership. Ingroup bias in emotional mimicryhas been well-documented in previous research; however, few studies have investigated the underlying mechanism. Based on the mimicry-as-social-regulator model, this study explored whether the ingroup bias in emotional mimicry arises from the greater self-ingroup overlap. By recording participants' facial electromyographic responses while passively viewing dynamic emotional clips performed by either racial ingroup or outgroup actors, Study 1 validated the presence of ingroup bias in the mimicry of happiness, but not anger. Using asimilar procedure in Study 2, anew sample was employed (N = 37), and a measurement of self-other overlaps via the Inclusion of the Other in the Self Scale was added. The results of Study 2 reproduced the ingroup bias in happy mimicry, and further demonstrated that the effect of group membership on emotional mimicry was mediated by the self-other overlap. In summary, this study provides evidence that the level of interpersonal closeness predicts emotional mimicry.

Association of masseter muscles thickness and facial morphology with facial expressions in children

OBJECTIVE

To evaluate the potential influence of muscular capacity and facial morphology on facial expressions in children.

MATERIALS AND METHODS

A cross-sectional study was carried out on 40 healthy children (ages 9-13), without previous orthodontic treatment. Masseter muscle thickness and anthropometric facial proportions were measured using ultrasound and digital calipers respectively. A three-dimensional infrared face-tracking system was used to register facial expressions. The maximal amplitude of smile and lip pucker (representing maximal lateral and medial commissure movement) were used for analysis. Stepwise regression was used to investigate whether muscle thickness or anthropometric facial proportions were associated with the quantity of commissure movement.

RESULTS

When performing maximal smile, children with thicker masseter muscles were found to have more limited displacement of the commissures (R = 0.39; p = 0.036). When performing lip pucker, children with thicker masseter muscles were found to have greater commissure movement (R = 0.40; p = 0.030). No significant associations were found between anthropometric facial proportions and facial expressions.

CONCLUSION

Masseter muscle thickness seems to be associated with facial expressions in children. Those with thicker muscles show more limited commissure movement when smiling, but greater movement with lip pucker. This indicates that masticatory muscles may serve as a surrogate for mimic muscle activity. Facial morphology of the subjects does not seem to be associated with facial expression.

Automatic facial coding versus electromyography of mimicked, passive, and inhibited facial response to emotional faces

Decoding someone's facial expressions provides insights into his or her emotional experience. Recently, Automatic Facial Coding (AFC) software has been developed to provide measurements of emotional facial expressions. Previous studies provided first evidence for the sensitivity of such systems to detect facial responses in study participants. In the present experiment, we set out to generalise these results to affective responses as they can occur in variable social interactions. Thus, we presented facial expressions (happy, neutral, angry) and instructed participants (N = 64) to either actively mimic, to look at them passively (n = 21), or to inhibit their own facial reaction (n = 22). A video stream for AFC and an electromyogram (EMG) of the zygomaticus and corrugator muscles were registered continuously. In the mimicking condition, both AFC and EMG differentiated well between facial expressions in response to the different emotional pictures. In the passive viewing and in the inhibition condition AFC did not detect changes in facial expressions whereas EMG was still highly sensitive. Although only EMG is sensitive when participants intend to conceal their facial reactions, these data extend previous findings that Automatic Facial Coding is a promising tool for the detection of intense facial reaction.

Electromyographic evidence of reduced emotion mimicry in individuals with a history of non-suicidal self-injury

Engaging in facial emotion mimicry during social interactions encourages empathy and functions as a catalyst for interpersonal bonding. Decreased reflexive mirroring of facial expressions has been observed in individuals with different non-psychotic disorders, relative to healthy controls. Given reports of interpersonal relationship difficulties experienced by those who engage in non-suicidal self-injury (NSSI), it is of interest to explore facial emotion mimicry in individuals with a history of this behaviour (HNSSI). Among other things, this will enable us to better understand their emotion regulation and social interaction challenges. Surface facial electromyography (fEMG) was used to record the reflexive facial mimicry of 30 HNSSI and 30 controls while they passively observed a series of dynamic facial stimuli showing various facial expressions of emotion. Beginning with a neutral expression, the stimuli quickly morphed to one of 6 prototypic emotional expressions (anger, fear, surprise, disgust, happiness, or sadness). Mimicry was assessed by affixing surface electrodes to facial muscles known to exhibit a high degree of electrical activity in response to positive and negative emotions: the corrugator supercilii and the zygomaticus major. HNSSI participants, relative to controls, exhibited significantly less electrical activity in the corrugator muscle in response to viewing angry stimuli, and significantly less of an expected relaxation in muscle activity in response to viewing happy stimuli. Mirroring these results, greater endorsement of social influence as a motivator for engaging in NSSI was associated with less mimicry, and greater endorsement of emotion regulation as a motivator was associated with greater incongruent muscle response when viewing happy faces. These findings lend support to the theory that social interaction difficulties in HNSSI might be related to implicit violations of expected social rules exhibited through facial mimicry nonconformity.

Is the Putative Mirror Neuron System Associated with Empathy? A Systematic Review and Meta-Analysis

Theoretical perspectives suggest that the mirror neuron system (MNS) is an important neurobiological contributor to empathy, yet empirical support is mixed. Here, we adopt a summary model for empathy, consisting of motor, emotional, and cognitive components of empathy. This review provides an overview of existing empirical studies investigating the relationship between putative MNS activity and empathy in healthy populations. 52 studies were identified that investigated the association between the MNS and at least one domain of empathy, representing data from 1044 participants. Our results suggest that emotional and cognitive empathy are moderately correlated with MNS activity, however, these domains were mixed and varied across techniques used to acquire MNS activity (TMS, EEG, and fMRI). Few studies investigated motor empathy, and of those, no significant relationships were revealed. Overall, results provide preliminary evidence for a relationship between MNS activity and empathy. However, our findings highlight methodological variability in study design as an important factor in understanding this relationship. We discuss limitations regarding these methodological variations and important implications for clinical and community translations, as well as suggestions for future research.

Right Temporoparietal Junction Modulates In-Group Bias in Facial Emotional Mimicry: A tDCS Study

The present study employs transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, to explore the possible role of the right temporoparietal junction (rTPJ) in regulating in-group bias in facial emotional mimicry. Participants received either anodal or cathodal stimulation, or they were assigned to a sham condition. After that, they passively viewed a series of video clips depicting different emotions (happiness and anger) that were performed either by ethnic in-group or out-group models. The emotion-specific muscle activities, zygomatic major (ZM) and corrugator supercilii (CS) were recorded simultaneously as the index of facial emotional mimicry. The results first confirm the in-group bias in facial emotional mimicry in the sham condition, as shown in prior studies, though it only occurs in happy mimicry. Moreover, the in-group bias in facial emotional mimicry is modulated by the cortical excitability over the rTPJ, which may be attributed to the accompanied change of overlap of the mental representations of in-group and out-group. This study provides a close look at the neural underpinning of the modulation of facial emotional mimicry by group membership and highlights the role of rTPJ in on-line control of co-activated self and other representations in social cognition.

Blocking facial mimicry affects recognition of facial and body expressions

Facial mimicry is commonly defined as the tendency to imitate-at a sub-threshold level-facial expressions of other individuals. Numerous studies support a role of facial mimicry in recognizing others' emotions. However, the underlying functional mechanism is unclear. A prominent hypothesis considers facial mimicry as based on an action-perception loop, leading to the prediction that facial mimicry should be observed only when processing others' facial expressions. Nevertheless, previous studies have also detected facial mimicry during observation of emotional bodily expressions. An emergent alternative hypothesis is that facial mimicry overtly reflects the simulation of an "emotion", rather than the reproduction of a specific observed motor pattern. In the present study, we tested whether blocking mimicry ("Bite") on the lower face disrupted recognition of happy expressions conveyed by either facial or body expressions. In Experiment 1, we tested participants' ability to identify happy, fearful and neutral expressions in the Bite condition and in two control conditions. In Experiment 2, to ensure that such a manipulation selectively affects emotion recognition, we tested participants' ability to recognize emotional expressions, as well as the actors' gender, under the Bite condition and a control condition. Finally, we investigated the relationship between dispositional empathy and emotion recognition under the condition of blocked mimicry. Our findings demonstrated that blocking mimicry on the lower face hindered recognition of happy facial and body expressions, while the recognition of neutral and fearful expressions was not affected by the mimicry manipulation. The mimicry manipulation did not affect the gender discrimination task. Furthermore, the impairment of happy expression recognition correlated with empathic traits. These results support the role of facial mimicry in emotion recognition and suggest that facial mimicry reflects a global sensorimotor simulation of others' emotions rather than a muscle-specific reproduction of an observed motor expression.

Approach and avoidance patterns in reward learning across domains: An initial examination of the Social Iowa Gambling Task

The current study examines learning patterns in response to both monetary and social incentives through both approach and avoidance behaviors using modified versions of the Iowa Gambling Task. Specifically, we investigated learning in response to both positive and negative feedback in a sample of 191 undergraduate students. The social task was a novel paradigm, and social feedback were images of faces displaying positive and negative emotions. We examined internal validity of the tasks through modeling changes in approach and avoidance. We also explored associations between approach and avoidance learning and individual differences in anxiety and social anxiety, depression and well-being, general anhedonia and social closeness, and fun-seeking, using multilevel models (MLMs). Results showed that both the monetary and social tasks demonstrated learning as shown by decreases in plays on disadvantageous decks across the task. Additionally, we found that overall task performance on the monetary task was associated with fun-seeking and overall task performance on the social task was associated with fun-seeking and depressive symptoms. Initial findings suggest promise for the novel task in the examination of social avoidance learning.

Widespread and lateralized social brain activity for processing dynamic facial expressions

Dynamic facial expressions of emotions constitute natural and powerful means of social communication in daily life. A number of previous neuroimaging studies have explored the neural mechanisms underlying the processing of dynamic facial expressions, and indicated the activation of certain social brain regions (e.g., the amygdala) during such tasks. However, the activated brain regions were inconsistent across studies, and their laterality was rarely evaluated. To investigate these issues, we measured brain activity using functional magnetic resonance imaging in a relatively large sample (n = 51) during the observation of dynamic facial expressions of anger and happiness and their corresponding dynamic mosaic images. The observation of dynamic facial expressions, compared with dynamic mosaics, elicited stronger activity in the bilateral posterior cortices, including the inferior occipital gyri, fusiform gyri, and superior temporal sulci. The dynamic facial expressions also activated bilateral limbic regions, including the amygdalae and ventromedial prefrontal cortices, more strongly versus mosaics. In the same manner, activation was found in the right inferior frontal gyrus (IFG) and left cerebellum. Laterality analyses comparing original and flipped images revealed right hemispheric dominance in the superior temporal sulcus and IFG and left hemispheric dominance in the cerebellum. These results indicated that the neural mechanisms underlying processing of dynamic facial expressions include widespread social brain regions associated with perceptual, emotional, and motor functions, and include a clearly lateralized (right cortical and left cerebellar) network like that involved in language processing.

Empathic Responses for Pain in Facial Muscles Are Modulated by Actor's Attractiveness and Gender, and Perspective Taken by Observer

Although empathy for pain is an often studied phenomenon, only few studies employing electromyography (EMG) have investigated either emotional responses to the pain of others or factors that modulate these responses. The present study investigated whether the sex and attractiveness of persons experiencing pain affected muscle activity associated with empathy for pain, the corrugator supercili (CS) and orbicularis oculi (OO) muscles, in male and female participants in two conditions: adopting a perspective of “the other” or “the self.” Fifty one participants (27 females) watched movies showing situations that included the expression of pain, with female and male and more and less attractive actors under both conditions, while the CS and OO EMG were recorded. Perspective did not affect CS muscle activity, but OO muscle activity tended to be higher in women than men under the imagine-self condition. CS muscle activity, but not OO muscle activity, was modulated by the actors’ gender and attractiveness. CS muscle activity was stronger in response to the pain of less attractive than more attractive actors, and to the pain of female actors compared to male actors. Moreover, a positive correlation was found between empathic concern, as a trait, and CS muscle activity, but only in the imagine-self condition.

Empathy in Facial Mimicry of Fear and Disgust: Simultaneous EMG-fMRI Recordings During Observation of Static and Dynamic Facial Expressions

Real-life faces are dynamic by nature, particularly when expressing emotion. Increasing evidence suggests that the perception of dynamic displays enhances facial mimicry and induces activation in widespread brain structures considered to be part of the mirror neuron system, a neuronal network linked to empathy. The present study is the first to investigate the relations among facial muscle responses, brain activity, and empathy traits while participants observed static and dynamic (videos) facial expressions of fear and disgust. During display presentation, blood-oxygen level-dependent (BOLD) signal as well as muscle reactions of the corrugator supercilii and levator labii were recorded simultaneously from 46 healthy individuals (21 females). It was shown that both fear and disgust faces caused activity in the corrugator supercilii muscle, while perception of disgust produced facial activity additionally in the levator labii muscle, supporting a specific pattern of facial mimicry for these emotions. Moreover, individuals with higher, compared to individuals with lower, empathy traits showed greater activity in the corrugator supercilii and levator labii muscles; however, these responses were not differentiable between static and dynamic mode. Conversely, neuroimaging data revealed motion and emotional-related brain structures in response to dynamic rather than static stimuli among high empathy individuals. In line with this, there was a correlation between electromyography (EMG) responses and brain activity suggesting that the Mirror Neuron System, the anterior insula and the amygdala might constitute the neural correlates of automatic facial mimicry for fear and disgust. These results revealed that the dynamic property of (emotional) stimuli facilitates the emotional-related processing of facial expressions, especially among whose with high trait empathy.

Adults' facial reaction to affective facial expressions of children and adults

Facial mimicry, the unconscious imitation of others' affective facial expressions, serves as an important basis for interpersonal communication. Although there are many studies dealing with this phenomenon regarding the interaction between adults, only few experiments have explored facial mimicry in response to affective facial expressions of children. In the following study affect-prototypical video clips of children's and adults' faces were presented to 44 adults while the activity of corrugator supercilii and zygomaticus muscles was electromyographically measured. A discrete mimic reaction was detected in response to each basic affect (fear, disgust, happiness, sadness, surprise and anger). The activity of corrugator supercilii muscle was significantly lower when affective facial expressions of children were presented in contrast to those of adults. In addition, negative correlations between alexithymia and the averaged facial EMG activity were detected.

Empowering Mimicry: Female Leader Role Models Empower Women in Leadership Tasks Through Body Posture Mimicry

In two studies we investigated the behavioral process through which visible female leader role models empower women in leadership tasks. We proposed that women tend to mimic the powerful (open) body postures of successful female role models, thus leading to more empowered behavior and better performance on a challenging leadership task, a process we called empowering mimicry. In Study 1, we experimentally manipulated the body posture of the male and female role models and showed that 86 Swiss college women mimicked the body posture of the female (ingroup) but not the male (outgroup) role model, thus leading to more empowered behavior and better performance on a public speaking task. In Study 2, we investigated the boundary conditions of this process and showed that empowering mimicry does not extend to exposures to non-famous female models among 50 Swiss college women. These findings suggest that nonverbal mimicry is one important mechanism through which female leader role models inspire women performing a challenging leadership task. From a practice perspective, our research underscores the importance of female leaders' visibility because visibility can drive other women's advancement in leadership by affording women the opportunity to mimic and be empowered by successful female role models.

Compositionality in the language of emotion

Emotions are signaled by complex arrays of face and body actions. The main point of contention in contemporary treatments is whether these arrays are discrete, holistic constellations reflecting emotion categories, or whether they are compositional-comprised of smaller components, each of which contributes some aspect of emotion to the complex whole. We address this question by investigating spontaneous face and body displays of athletes and place it in the wider context of human communicative signals and, in particular, of language. A defining property of human language is compositionality-the ability to combine and recombine a relatively small number of elements to create a vast number of complex meaningful expressions, and to interpret them. We ask whether this property of language can be discerned in a more ancient communicative system: intense emotional displays. In an experiment, participants interpreted a range of emotions and their strengths in pictures of athletes who had just won or lost a competition. By matching participants' judgements with minutely coded features of face and body, we find evidence for compositionality. The distribution of participants' responses indicates that most of the athletes' face and body features contribute to displays of dominance or submission. More particular emotional components related, for example, to positive valence (e.g. happy) or goal obstruction (e.g. frustrated), were also found to significantly correlate with certain face and body features. We propose that the combination of features linked to broader components (i.e, dominant or submissive) and to more particular emotions (e.g, happy or frustrated) reflects more complex emotional states. In sum, we find that the corporeal expression of intense, unfiltered emotion has compositional properties, potentially providing an ancient scaffolding upon which, millions of years later, the abstract and constrained compositional system of human language could build.

Alexithymia Is Related to the Need for More Emotional Intensity to Identify Static Fearful Facial Expressions

Individuals with high levels of alexithymia, a personality trait marked by difficulties in identifying and describing feelings and an externally oriented style of thinking, appear to require more time to accurately recognize intense emotional facial expressions (EFEs). However, in everyday life, EFEs are displayed at different levels of intensity and individuals with high alexithymia may also need more emotional intensity to identify EFEs. Nevertheless, the impact of alexithymia on the identification of EFEs, which vary in emotional intensity, has largely been neglected. To address this, two experiments were conducted in which participants with low (LA) and high (HA) levels of alexithymia were assessed in their ability to identify static (Experiment 1) and dynamic (Experiment 2) morphed faces ranging from neutral to intense EFEs. Results showed that HA needed more emotional intensity than LA to identify static fearful – but not happy or disgusted – faces. On the contrary, no evidence was found that alexithymia affected the identification of dynamic EFEs. These results extend current literature suggesting that alexithymia is related to the need for more perceptual information to identify static fearful EFEs.

Dynamics Matter: Recognition of Reward, Affiliative, and Dominance Smiles From Dynamic vs. Static Displays

Smiles are distinct and easily recognizable facial expressions, yet they markedly differ in their meanings. According to a recent theoretical account, smiles can be classified based on three fundamental social functions which they serve: expressing positive affect and rewarding self and others (reward smile), creating and maintaining social bonds (affiliative smile), and negotiating social status (dominance smiles) (Niedenthal et al., 2010; Martin et al., 2017). While there is evidence for distinct morphological features of these smiles, their categorization only starts to be investigated in human faces. Moreover, the factors influencing this process - such as facial mimicry or display mode - remain yet unknown. In the present study, we examine the recognition of reward, affiliative, and dominance smiles in static and dynamic portrayals, and explore how interfering with facial mimicry affects such classification. Participants (N = 190) were presented with either static or dynamic displays of the three smile types, whilst their ability to mimic was free or restricted via a pen-in-mouth procedure. For each stimulus they rated the extent to which the expression represents a reward, an affiliative, or a dominance smile. Higher than chance accuracy rates revealed that participants were generally able to differentiate between the three smile types. In line with our predictions, recognition performance was lower in the static than dynamic condition, but this difference was only significant for affiliative smiles. No significant effects of facial muscle restriction were observed, suggesting that the ability to mimic might not be necessary for the distinction between the three functional smiles. Together, our findings support previous evidence on reward, affiliative, and dominance smiles by documenting their perceptual distinctiveness. They also replicate extant observations on the dynamic advantage in expression perception and suggest that this effect may be especially pronounced in the case of ambiguous facial expressions, such as affiliative smiles.

Emotional facial expressions during REM sleep dreams

Although motor activity is actively inhibited during rapid eye movement (REM) sleep, specific activations of the facial mimetic musculature have been observed during this stage, which may be associated with greater emotional dream mentation. Nevertheless, no specific biomarker of emotional valence or arousal related to dream content has been identified to date. In order to explore the electromyographic (EMG) activity (voltage, number, density and duration) of the corrugator and zygomaticus major muscles during REM sleep and its association with emotional dream mentation, this study performed a series of experimental awakenings after observing EMG facial activations during REM sleep. The study was performed with 12 healthy female participants using an 8-hr nighttime sleep recording. Emotional tone was evaluated by five blinded judges and final valence and intensity scores were obtained. Emotions were mentioned in 80.4% of dream reports. The voltage, number, density and duration of facial muscle contractions were greater for the corrugator muscle than for the zygomaticus muscle, whereas high positive emotions predicted the number (R² 0.601, p = 0.0001) and voltage (R² 0.332, p = 0.005) of the zygomaticus. Our findings suggest that zygomaticus events were predictive of the experience of positive affect during REM sleep in healthy women.

Cardiac responses to viewing facial emotion differentiate frontotemporal dementias

Objective

To establish proof‐of‐principle for the use of heart rate responses as objective measures of degraded emotional reactivity across the frontotemporal dementia spectrum, and to demonstrate specific relationships between cardiac autonomic responses and anatomical patterns of neurodegeneration.

Methods

Thirty‐two patients representing all major frontotemporal dementia syndromes and 19 healthy older controls performed an emotion recognition task, viewing dynamic, naturalistic videos of facial emotions while ECG was recorded. Cardiac reactivity was indexed as the increase in interbeat interval at the onset of facial emotions. Gray matter associations of emotional reactivity were assessed using voxel‐based morphometry of patients’ brain MR images.

Results

Relative to healthy controls, all patient groups had impaired emotion identification, whereas cardiac reactivity was attenuated in those groups with predominant fronto‐insular atrophy (behavioral variant frontotemporal dementia and nonfluent primary progressive aphasia), but preserved in syndromes focused on the anterior temporal lobes (right temporal variant frontotemporal dementia and semantic variant primary progressive aphasia). Impaired cardiac reactivity correlated with gray matter atrophy in a fronto‐cingulo‐insular network that overlapped correlates of cognitive emotion processing.

Interpretation

Autonomic indices of emotional reactivity dissociate from emotion categorization ability, stratifying frontotemporal dementia syndromes and showing promise as novel biomarkers. Attenuated cardiac responses to the emotions of others suggest a core pathophysiological mechanism for emotional blunting and degraded interpersonal reactivity in these diseases.

Recognition of emotional facial expressions in benzodiazepine dependence and detoxification

INTRODUCTION

The study investigates how benzodiazepine (BZD) use and detoxification affects empathy and the recognition and intensity rating of emotional facial expressions. The sample comprised 43 participants in three groups: (1) during detoxification (N = 13), (2) after detoxification (N = 15), (3) a matched control group (N = 15). Clinical subjects were recruited from in-patients of an addiction treatment unit.

METHODS

Empathy levels were tested with the Empathy Quotient (EQ-Short). Recognition accuracy and emotion intensity rating were based on a computerised task displaying static and dynamic facial expressions of joy, anger, sadness, and fear.

RESULTS

The controls proved more accurate than both experimental groups in identifying facial expressions of negative emotions. Joy recognition proved most accurate overall. Among the clinical subjects, women in particular exhibited an impaired ability to correctly identify negative emotions from facial expressions. Dynamic stimuli were better recognised than static ones albeit only in the experimental groups. No significant differences were found for emotion intensity ratings and EQ scores.

CONCLUSION

Our findings suggest that the impaired facial emotion recognition accuracy is not caused by deficits in empathy. No improvement was recorded post-detoxification which may indicate impaired interpersonal functioning among BZD users. Further research is warranted in light of this study's limitations.

Neural Correlates of Facial Mimicry: Simultaneous Measurements of EMG and BOLD Responses during Perception of Dynamic Compared to Static Facial Expressions

Facial mimicry (FM) is an automatic response to imitate the facial expressions of others. However, neural correlates of the phenomenon are as yet not well established. We investigated this issue using simultaneously recorded EMG and BOLD signals during perception of dynamic and static emotional facial expressions of happiness and anger. During display presentations, BOLD signals and zygomaticus major (ZM), corrugator supercilii (CS) and orbicularis oculi (OO) EMG responses were recorded simultaneously from 46 healthy individuals. Subjects reacted spontaneously to happy facial expressions with increased EMG activity in ZM and OO muscles and decreased CS activity, which was interpreted as FM. Facial muscle responses correlated with BOLD activity in regions associated with motor simulation of facial expressions [i.e., inferior frontal gyrus, a classical Mirror Neuron System (MNS)]. Further, we also found correlations for regions associated with emotional processing (i.e., insula, part of the extended MNS). It is concluded that FM involves both motor and emotional brain structures, especially during perception of natural emotional expressions.

Motor signatures of emotional reactivity in frontotemporal dementia

Automatic motor mimicry is essential to the normal processing of perceived emotion, and disrupted automatic imitation might underpin socio-emotional deficits in neurodegenerative diseases, particularly the frontotemporal dementias. However, the pathophysiology of emotional reactivity in these diseases has not been elucidated. We studied facial electromyographic responses during emotion identification on viewing videos of dynamic facial expressions in 37 patients representing canonical frontotemporal dementia syndromes versus 21 healthy older individuals. Neuroanatomical associations of emotional expression identification accuracy and facial muscle reactivity were assessed using voxel-based morphometry. Controls showed characteristic profiles of automatic imitation, and this response predicted correct emotion identification. Automatic imitation was reduced in the behavioural and right temporal variant groups, while the normal coupling between imitation and correct identification was lost in the right temporal and semantic variant groups. Grey matter correlates of emotion identification and imitation were delineated within a distributed network including primary visual and motor, prefrontal, insular, anterior temporal and temporo-occipital junctional areas, with common involvement of supplementary motor cortex across syndromes. Impaired emotional mimesis may be a core mechanism of disordered emotional signal understanding and reactivity in frontotemporal dementia, with implications for the development of novel physiological biomarkers of socio-emotional dysfunction in these diseases.

Matching Your Face or Appraising the Situation: Two Paths to Emotional Contagion

Emotions are believed to converge both through emotional mimicry and social appraisal. The present study compared contagion of anger and happiness. In Experiment 1, participants viewed dynamic angry and happy faces, with facial electromyography recorded from the zygomaticus major and corrugator supercilii as emotional mimicry. Self-reported emotional experiences were analyzed as emotional contagion. Experiment 2 manipulated social appraisal as the gaze of expression toward the target. The results showed that there was emotional contagion for angry and happy expressions both in Experiment 1 and Experiment 2. Experiment 1 indicated an overt mimicry pattern for happy faces, but not for angry faces. Experiment 2 found an influence of social appraisal on angry contagion but not on happy diffusion. The two experiments suggest that the underlying processes of emotional mimicry and social appraisal are differentially relevant for different emotional contagion, with happiness processing following a mimicry-based path to emotional contagion, and anger processing requiring social appraisal.

Emotional Empathic Responses to Dynamic Negative Affective Stimuli Is Gender-Dependent

Empathy entails the ability to recognize emotional states in others and feel for them. Since empathy does not take place in a static setting, paradigms utilizing more naturalistic, dynamic stimuli instead of static stimuli are perhaps more suited to grasp the origin of this highly complex social skill. The study was set up to test the effect of stimulus dynamics and gender on empathic responses. Participants were 80 healthy volunteers (N = 40 males) aged 22.5 years on average. Behavioral empathy was tested with the multifaceted empathy test, including static emotional stimuli, and the multidimensional movie empathy test (MMET), including dynamic stimuli. Findings showed emotional empathy (EE) responses were higher to negative emotional stimuli in both tasks, i.e., using static as well as dynamic stimuli. Interestingly a gender-dependent response was only seen in the MMET using dynamic stimuli. It was shown that females felt more aroused and were more concerned with people in negative affective states. It was concluded that the MMET is suited to study gender differences in EE.

Emotional Empathy and Facial Mimicry for Static and Dynamic Facial Expressions of Fear and Disgust

Facial mimicry is the tendency to imitate the emotional facial expressions of others. Increasing evidence suggests that the perception of dynamic displays leads to enhanced facial mimicry, especially for happiness and anger. However, little is known about the impact of dynamic stimuli on facial mimicry for fear and disgust. To investigate this issue, facial EMG responses were recorded in the corrugator supercilii, levator labii, and lateral frontalis muscles, while participants viewed static (photos) and dynamic (videos) facial emotional expressions. Moreover, we tested whether emotional empathy modulated facial mimicry for emotional facial expressions. In accordance with our predictions, the highly empathic group responded with larger activity in the corrugator supercilii and levator labii muscles. Moreover, dynamic compared to static facial expressions of fear revealed enhanced mimicry in the high-empathic group in the frontalis and corrugator supercilii muscles. In the low-empathic group the facial reactions were not differentiated between fear and disgust for both dynamic and static facial expressions. We conclude that highly empathic subjects are more sensitive in their facial reactions to the facial expressions of fear and disgust compared to low empathetic counterparts. Our data confirms that personal characteristics, i.e., empathy traits as well as modality of the presented stimuli, modulate the strength of facial mimicry. In addition, measures of EMG activity of the levator labii and frontalis muscles may be a useful index of empathic responses of fear and disgust.