The antecedents and consequences of human behavioral mimicry

Sick and detached: Does experimental inflammation impact on movement synchrony in humans?

Interpersonal connectedness is a central feature of human interaction that can be compromised during illness. Nonverbal signals play a crucial role in this context, and humans, like other animals, have evolved a behavioral immune system that enables individuals to detect subtle cues of sickness in others. Conversely, sick individuals often tend to avoid social interaction, a key component of sickness behavior. The coordination of body movements between two individuals (movement synchrony) is a measure of the quality of relationships that could provide insights into an interlocutor's sickness state. In the present study, we explored the effect of lipopolysaccharide (LPS) administration, a naturalistic stimulus for inflammation-induced sickness, on movement synchrony in healthy volunteers randomly assigned to a double-blind interview with a non-treated interviewer conducted 2.5 h after intravenous injection of either LPS (N = 26) or placebo (N = 25). Movement synchrony was assessed by automated video analysis of subject's and interviewer's head movements. Lagged cross-correlations were used to objectively quantify coordination in dyads and to assess patterns of temporal movement synchronization. Data analysis revealed that dyads with subjects under placebo displayed a pattern of movement coordination comparable to that seen in previous studies. However, dyads with subjects under LPS showed a loss of simultaneous movement (i.e. moving at the same time) with the interview partner, which is normally the temporal domain providing the highest level of synchrony. Together, the findings suggest that immediate social interaction is attenuated when one interlocutor is exposed to systemic inflammation, while the other is unaffected. This effect can be attributed to both sickness behavior on one hand and correlates of the behavioral immune system on the other hand.

Why robot embodiment matters: questions of disability, race and intersectionality in the design of social robots

A growing minority of those with disabilities are people of color (POC), with, for example, autism diagnosis rates now higher for children of color than for white children in the USA. This trend underscores the need for assistive technologies, especially socially assistive robots, to be designed with intersectional users in mind. Outside of Japan, most robots are designed with white synthetic skin and able-bodied features, failing to reflect the diverse users they are meant to assist. This paper explores the concept of the "engineering imaginary," the historical and cultural influences that shape these designs, and which tend to limit robot embodiment to white, able-bodied forms. Drawing on work from scholars like Lucy Suchman, Jennifer Rhee, Neda Atanasoski and Kalindi Vora, the paper critiques this engineering bias. A key historical moment in the production of the engineered imaginary of artificial humans is provided by Ovid's myth of Pygmalion and its influence on representations across literature, film, and then robotics. Furthermore, the physicality of the robot, and its role in the production of nonverbal communication (NVC) for more inclusive interaction with humans is explored, seeing these as steps toward what some roboticists are calling Artificial Empathy (AE). Through case studies like Bestic, Bina48, and HuggieBot 3.0, the paper explores what I call the poverty of the engineering imaginary, how current robotics design fails to properly address issues of race, gender, and disability. Ultimately, the paper argues for more inclusive robot designs that accommodate diverse bodies and social dynamics, questioning the pervasive norm of white, able-bodied robotic embodiment.

Automatic imitation of intransitive actions in macaws

Automatic imitation is the involuntary tendency of humans to copy others' actions even when counterproductive. We examined the automatic imitation of intransitive actions in blue-throated macaws (Ara glaucogularis), employing a stimulus-response-compatibility task. After training seven macaws to perform two different actions with legs and wings upon specific hand commands, the subjects were divided into a compatible and incompatible group. We rewarded the subjects for performing the same action as the conspecific model in the compatible group and the opposite action in the incompatible group. Involuntarily imitating the demonstrated actions, the incompatible group made more errors than the compatible group and took longer to eventually respond correctly. The study provides evidence for the automatic imitation of intransitive actions in non-human animals- parrots, suggesting that arbitrary action imitation facilitated by a mirror-neuron system in parrot brain may be adaptive in the ever-changing complex social environment of parrots and possibly drive cultural evolution.

A modular machine learning tool for holistic and fine-grained behavioral analysis

Artificial intelligence techniques offer promising avenues for exploring human body features from videos, yet no freely accessible tool has reliably provided holistic and fine-grained behavioral analyses to date. To address this, we developed a machine learning tool based on a two-level approach: a first lower-level processing using computer vision for extracting fine-grained and comprehensive behavioral features such as skeleton or facial points, gaze, and action units; a second level of machine learning classification coupled with explainability providing modularity, to determine which behavioral features are triggered by specific environments. To validate our tool, we filmed 16 participants across six conditions, varying according to the presence of a person ("Pers"), a sound ("Snd"), or silence ("Rest"), and according to emotional levels using self-referential ("Self") and control ("Ctrl") stimuli. We demonstrated the effectiveness of our approach by extracting and correcting behavior from videos using two computer vision software (OpenPose and OpenFace) and by training two algorithms (XGBoost and long short-term memory [LSTM]) to differentiate between experimental conditions. High classification rates were achieved for "Pers" conditions versus "Snd" or "Rest" (AUC = 0.8-0.9), with explainability revealing actions units and gaze as key features. Additionally, moderate classification rates were attained for "Snd" versus "Rest" (AUC = 0.7), attributed to action units, limbs and head points, as well as for "Self" versus "Ctrl" (AUC = 0.7-0.8), due to facial points. These findings were consistent with a more conventional hypothesis-driven approach. Overall, our study suggests that our tool is well suited for holistic and fine-grained behavioral analysis and offers modularity for extension into more complex naturalistic environments.

Voice of a woman: influence of interaction partner characteristics on cycle dependent vocal changes in women

Introduction

Research has shown that women's vocal characteristics change during the menstrual cycle. Further, evidence suggests that individuals alter their voices depending on the context, such as when speaking to a highly attractive person, or a person with a different social status. The present study aimed at investigating the degree to which women's voices change depending on the vocal characteristics of the interaction partner, and how any such changes are modulated by the woman's current menstrual cycle phase.

Methods

Forty-two naturally cycling women were recorded once during the late follicular phase (high fertility) and once during the luteal phase (low fertility) while reproducing utterances of men and women who were previously assessed to have either attractive or unattractive voices.

Results

Phonetic analyses revealed that women's voices in response to speakers changed depending on their menstrual cycle phase (F0 variation, maximum F0, Centre of gravity) and depending on the stimulus speaker's vocal attractiveness (HNR, Formants 1-3, Centre of gravity), and sex (Formant 2). Also, the vocal characteristics differed when reproducing spoken sentences of the stimulus speakers compared to when they read out written sentences (minimum F0, Formants 2-4).

Discussion

These results provide further evidence that women alter their voice depending on the vocal characteristics of the interaction partner and that these changes are modulated by the menstrual cycle phase. Specifically, the present findings suggest that cyclic shifts on women's voices may occur only in social contexts (i.e., when a putative interaction partner is involved).

Food choice mimicry on a large university campus

Social influence is a strong determinant of food consumption, which in turn influences the environment and health. Purchasing mimicry, a phenomenon where a person copies another person's purchases, has been identified as the key governing mechanism. Although consistent observations have been made on the role of purchasing mimicry in driving similarities in food consumption, much less is known about the precise prevalence, the affected subpopulations, and the food types most strongly associated with mimicry effects. Here, we study social influence on food choice through carefully designed causal analyses, leveraging the sequential nature of shop queues on a large university campus. In particular, we consider a large number of adjacent purchases where a focal user immediately follows another user ("partner") in the checkout queue and both make a purchase. Across food additions purchased during lunchtime together with a meal, we find that the focal user is significantly more likely to purchase the food item when the partner buys the item, vs. when the partner does not, increasing the purchasing probability by 14% in absolute terms, or by 83% in relative terms. The effect is observed across all food types, but largest for condiments. Furthermore, purchasing mimicry is present across age, gender, and status subpopulations, but strongest for students and the youngest. We elucidate the behavioral mechanism of purchasing mimicry, and derive direct implications for interventions improving dietary behaviors on campus, such as facilitating preordering to reduce detrimental interactions.

A social information processing perspective on social connectedness

Social connectedness (SC) is one of the most important predictors for physical and mental health. Consequently, SC is addressed in an increasing number of studies, providing evidence for the multidimensionality of the construct, and revealing several factors that contribute to individual differences in SC. However, a unified model that can address SC subcomponents is yet missing. Here we take a novel perspective and discuss whether individual differences in SC can be explained by a person's social information processing profile that represents individual tendencies of how social information is perceived and interpreted and leads to motivated social behavior. After summarizing the current knowledge on SC and core findings from the fields of social perception and mentalizing, social motivation and social action, we derive a working model that links individual stages of social information processing to structural, functional, and qualitative aspects of SC. This model allows for deriving testable hypotheses on the foundations of SC and we outline several suggestions how these aspects can be addressed by future research.

Putting a label on someone: impact of schizophrenia stigma on emotional mimicry, liking, and interpersonal closeness

Affiliation is both an antecedent and a consequence of emotional mimicry (i.e. imitating a counterpart's emotional expression). Thus, interacting with a disliked partner can decrease emotional mimicry, which in turn can further decrease liking. This perpetuating circle has not been investigated in the context of mental health stigma yet. The present study tested the influence of the label "schizophrenia" on liking, interpersonal closeness, and emotional mimicry. In an online experiment (n = 201), participants recruited from the general population saw several videos of actors displaying emotional expressions. Actors were described with one of four labels: "schizophrenia", "healthy", "diabetes", and a negative adjective (e.g. "hot-tempered"). Emotional mimicry was measured using OpenFace 2.2. Liking and interpersonal closeness were assessed with questionnaires. Overall, compared to other labels, participants reported less liking and interpersonal closeness to the actor with the schizophrenia label. However, no effect on emotional mimicry was found. The decreased liking of the schizophrenia actors was explained by a lack of knowledge about schizophrenia and the explicit stigma of schizophrenia. Our study contributes to the literature by highlighting the need to reduce the stigma of schizophrenia.

Syncing online: A methodological investigation into movement synchrony, proxemics, and self-other blurring in virtual spaces

A growing body of literature has found that synchronising movements with a group subsequently increases self-other blurring and social closeness with synchronised partners. However, movement synchrony has not been studied in online settings. Our study has a primarily methodological focus to investigate whether synchronous movement leads to changes in self-other blurring and proxemics in an online, desktop-mediated environment. We conducted two experiments to manipulate synchrony with a group of virtual agents and investigate its impact on self-other blurring and comfort distance judgments. In Experiment 1, we compared synchronous movement to a no-movement condition; in Experiment 2, we introduced an unpredictable movement condition. In both experiments, we found that our manipulation of synchronous movement between participants and a virtual group of agents led to an increase in explicit self-other blurring compared to the no and unpredictable movement conditions; however, we did not find reliable effects on comfort distance judgments.

Mutual gaze and movement synchrony boost observers' enjoyment and perception of togetherness when watching dance duets

As social beings, we are adept at coordinating our body movements and gaze with others. Often, when coordinating with another person, we orient ourselves to face them, as mutual gaze provides valuable cues pertaining to attention and intentions. Moreover, movement synchrony and mutual gaze are associated with prosocial outcomes, yet the perceptual consequences of these forms of coordination remain poorly understood. Across two experiments, we assessed how movement synchrony and gaze direction influence observers' perceptions of dyads. Observers' behavioural responses indicated that dyads are perceived as more socially connected and are more enjoyable to watch when moving synchronously and facing each other. Neuroimaging results showed modulation of the Action Observation and Theory of Mind networks by movement synchrony and mutual gaze, with more robust brain activity when evaluating togetherness (i.e., active and intentional collaboration) than aesthetic value (i.e., enjoyment). A fuller understanding of the consequences of movement synchrony and mutual gaze from the observer's viewpoint holds important implications for social perception, in terms of how observers intuit social relationships within dyads, and the aesthetic value derived from watching individuals moving in these ways.

Establishing trust with children

Trust forms the bedrock of the doctor-patient relationship. While establishing trust is a foundational skill for healthcare providers who care for children, there is no systematic approach to teaching this skill set, nor is there formal training during medical school or residency. Traditionally, these skills have been taught by example, in an unstructured and ad hoc manner, with trainees picking it up along the way by observing and modeling their instructors. Here, we define and examine the elements of establishing trust and describe a methodology for establishing trust and managing a child's emotional state during medical encounters.

Higher or lower? Interpersonal behavioral and neural synchronization of movement imitation in autistic children

How well autistic children can imitate movements and how their brain activity synchronizes with the person they are imitating have been understudied. The current study adopted functional near-infrared spectroscopy (fNIRS) hyperscanning and employed a task involving real interactions involving meaningful and meaningless movement imitation to explore the fundamental nature of imitation as a dynamic and interactive process. Experiment 1 explored meaningful and meaningless gesture imitation. The results revealed that autistic children exhibited lower imitation accuracy and behavioral synchrony than non-autistic children when imitating both meaningful and meaningless gestures. Specifically, compared to non-autistic children, autistic children displayed significantly higher interpersonal neural synchronization (INS) in the right inferior parietal lobule (r-IPL) (channel 12) when imitating meaningful gestures but lower INS when imitating meaningless gestures. Experiment 2 further investigated the imitation of four types of meaningless movements (orofacial movements, transitive movements, limb movements, and gestures). The results revealed that across all four movement types, autistic children exhibited significantly lower imitation accuracy, behavioral synchrony, and INS in the r-IPL (channel 12) than non-autistic children. This study is the first to identify INS as a biomarker of movement imitation difficulties in autistic individuals. Furthermore, an intra- and interindividual imitation mechanism model was proposed to explain the underlying causes of movement imitation difficulties in autistic individuals.

A social cognition perspective on misophonia

Misophonia is commonly classified by intense emotional reactions to common everyday sounds. The condition has an impact both on the mental health of its sufferers and societally. As yet, formal models on the basis of misophonia are in their infancy. Based on developing behavioural and neuroscientific research we are gaining a growing understanding of the phenomenology and empirical findings in misophonia, such as the importance of context, types of coping strategies used and the activation of particular brain regions. In this article, we argue for a model of misophonia that includes not only the sound but also the context within which sound is perceived and the emotional reaction triggered. We review the current behavioural and neuroimaging literature, which lends support to this idea. Based on the current evidence, we propose that misophonia should be understood within the broader context of social perception and cognition, and not restricted within the narrow domain of being a disorder of auditory processing. We discuss the evidence in support of this hypothesis, as well as the implications for potential treatment approaches. This article is part of the theme issue 'Sensing and feeling: an integrative approach to sensory processing and emotional experience'.

The effect of non-verbal mimicry on evaluations in interactions with cognitively (dis)similar individuals

Non-verbal mimicry (i.e., being posturally similar by copying another person's body language) has been shown to increase evaluations of the mimicker. Concurrently, extensive research in social psychology has demonstrated a negative effect on interpersonal evaluations when one perceives others as cognitively dissimilar, often resulting in interpersonal conflicts. Across two experiments (Experiment 1: N = 159, Experiment 2: N = 144), we tested our hypotheses that mimicry, compared with no mimicry, will make mimickers come across as more likable and competent regardless of whether they were perceived as cognitively dissimilar or not (Experiment 1) and regardless of the extent to which they were perceived as cognitively dissimilar (Experiment 2). Broadly, we found support for our hypotheses, and via mediation sensitivity analyses, we found that the effect of mimicry, at least for likability, was mediated by participants' perceived personal similarity to the mimicker. Non-verbal mimicry may thus be one way of alleviating interpersonal conflicts via increasing perceptions of personal similarity regardless of initial cognitive dissimilarity.

Intergenerational Synchrony and Its Effect on Bonding and Group Closeness among Young and Older Adults

To examine the effect of synchronous dance movements on social bonding and perceived closeness between generations, 168 young (20-45 years) and older (65-90 years) participants were randomly assigned to six dyad conditions. These included dancing synchronously or asynchronously with an in-age-group or out-age-group unfamiliar partner for 11 min. The participants then completed social bonding and group closeness questionnaires. To assess variation across individuals' and dyads' measurements, a generalized estimating equation modeling analysis was conducted. In line with the hypotheses, synchronized dancing increased social bonding, and young adults showed an enhanced perception of closeness between generations. The hypothesis that synchronous dancing with out-age-group members would foster greater perceived closeness compared to in-age-group members was not confirmed. Surprisingly, the results indicated that asynchronous movements with the in-age-group led to a higher degree of closeness between generations than asynchronous movements with the out-age-group. Avenues for future studies on the mechanisms by which intergenerational dance fosters intergenerational bonding and closeness are discussed.

Social motor synchrony in autism spectrum conditions: A systematic review

LAY ABSTRACT

When two people interact, they often fall into sync with one another by moving their bodies at the same time. Some say autistic people are not as good as non-autistic people at moving at the same time as a partner. This has led some researchers to ask whether measuring synchrony might help diagnose autism. We reviewed the research so far to look at differences in Social Motor Synchrony (SMS) (the way we move together) between autistic people and people they interact with. The research suggests that interactions involving an autistic partner (either two autistic partners, or an autistic and non-autistic partner) show lower synchrony than a non-autistic pair. However, we recognised elements in the research so far that may have affected SMS in interactions involving an autistic person. One way SMS may have been affected in research so far might be the way interactions have been set up in the research studies. Few papers studied interactions between two autistic people or looked at synchrony in comfortable environments with autistic-preferred tasks. The studies also do not explain why synchrony might be different, or weaker, in pairs involving autistic partners. We use these limitations to suggest improvements for future research.

Sensorimotor regulation of facial expression - An untouched frontier

Facial expression is a critical form of nonverbal social communication which promotes emotional exchange and affiliation among humans. Facial expressions are generated via precise contraction of the facial muscles, guided by sensory feedback. While the neural pathways underlying facial motor control are well characterized in humans and primates, it remains unknown how tactile and proprioceptive information reaches these pathways to guide facial muscle contraction. Thus, despite the importance of facial expressions for social functioning, little is known about how they are generated as a unique sensorimotor behavior. In this review, we highlight current knowledge about sensory feedback from the face and how it is distinct from other body regions. We describe connectivity between the facial sensory and motor brain systems, and call attention to the other brain systems which influence facial expression behavior, including vision, gustation, emotion, and interoception. Finally, we petition for more research on the sensory basis of facial expressions, asserting that incomplete understanding of sensorimotor mechanisms is a barrier to addressing atypical facial expressivity in clinical populations.

Dyadic body competence predicts movement synchrony during the mirror game

The process of synchronizing our body movements with others is known to enhance rapport, affect, and prosociality. Furthermore, emerging evidence suggests that synchronizing activities may enhance cognitive performance. Unknown, by contrast, is the extent to which people's individual traits and experiences influence their ability to achieve and maintain movement synchrony with another person, which is key for unlocking the social and affective benefits of movement synchrony. Here, we take a dyad-centered approach to gain a deeper understanding of the role of embodiment in achieving and maintaining movement synchrony. Using existing data, we explored the relationship between body competence and body perception scores at the level of the dyad, and the dyad's movement synchrony and complexity while playing a 2.5-min movement mirroring game. The data revealed that dyadic body competence scores positively correlate with movement synchrony, but not complexity, and that dyadic body perception scores are not associated with movement synchrony or complexity. Movement synchrony was greater when the more experienced member of the dyad was responsible for copying movements. Finally, movement synchrony and complexity were stable across the duration of the mirror game. These findings show that movement synchrony is sensitive to the composition of the dyad involved, specifically the dyad's embodiment, illuminating the value of dyadic approaches to understanding body movements in social contexts.

Exploring the role of emotions and conversation content in interpersonal synchrony: A case study of a couple therapy session

OBJECTIVE

This exploratory study investigated the association between interpersonal movement and physiological synchronies, emotional processing, and the conversational structure of a couple therapy session using a multimodal, mixed-method approach.

METHOD

The video recordings of a couple therapy session, in which the participants' electrodermal activity was recorded, were analyzed. The session was divided into topical episodes, a qualitative analysis was conducted on each topical episode's emotional aspects, conversational structure and content. In addition, movement and physiological synchrony were calculated in each topical episode. Regression models were used to discover the associations between qualitative variables and synchronies.

RESULTS

Physiological synchrony was associated with the emotional aspects of the session and to episodes in which the spouses' relationship was addressed, while movement synchrony was only related to emotional valence. No association between synchrony and conversational structure was found.

CONCLUSION

The findings suggest that physiological and movement synchrony play distinct roles in psychotherapy. The exploratory study sheds light on the association between momentary synchrony, emotions, and conversational structure in a couple therapy session.

Covert and overt automatic imitation are correlated

Most theoretical accounts of imitation assume that covert and overt measures of automatic imitation tap into the same underlying construct. Despite this widespread assumption, it is not well supported by empirical evidence. In fact, the only study investigating the relation between covert and overt automatic imitation failed to find a correlation between them (Genschow et al., 2017, PLOS ONE, 12[9], Article e0183784). However, because overt and covert imitation were measured using two very different tasks, and because the measure of overt imitation was found to be unreliable, it is still not clear whether a correlation between both measures exists. Here, we address this question by reanalyzing the results of a previous virtual reality study in which automatic imitation was indexed with an overt and covert measure of gaze following, both obtained within one and the same task (Cracco et al., 2022, IScience, Article 104891). The results show that, in this situation, both types of imitation do correlate. As such, our results provide support for the idea that overt and covert measures of automatic imitation measure the same underlying construct.

How and Why People Synchronize: An Integrated Perspective

Academic AbstractInterpersonal synchrony, the alignment of behavior and/or physiology during interactions, is a pervasive phenomenon observed in diverse social contexts. Here we synthesize across contexts and behaviors to classify the different forms and functions of synchrony. We provide a concise framework for classifying the manifold forms of synchrony along six dimensions: periodicity, discreteness, spatial similarity, directionality, leader-follower dynamics, and observability. We also distill the various proposed functions of interpersonal synchrony into four interconnected functions: reducing complexity and improving understanding, accomplishing joint tasks, strengthening social connection, and influencing partners' behavior. These functions derive from first principles, emerge from each other, and are accomplished by some forms of synchrony more than others. Effective synchrony flexibly adapts to social goals and more synchrony is not always better. Our synthesis offers a shared framework and language for the field, allowing for better cross-context and cross-behavior comparisons, generating new hypotheses, and highlighting future research directions.

Diffusive coupling facilitates and impedes noise-induced escape in interacting bistable elements

Diverse complex systems often undergo sudden changes in their states, such as epileptic seizures, climate changes, and social uprisings. Such behavior has been modeled by noise-induced escape of bistable elements, which is the escape from an attracting state driven by a fluctuation in the system's state. We consider a system of interacting bistable elements and investigate the effect of diffusive coupling among elements on the process of noise-induced escape. We focus on the influence of the coupling strength over the escape time, which is the time it takes for noise-induced escape to occur. We performed numerical simulations and observed that weak coupling reduced the mean escape time, whereas strong coupling impeded escape. We argue that, although diffusive coupling both facilitates and impedes escape, the facilitating effect is dominant when coupling is weak. For weak coupling cases, we develop an approximate theory that can predict the mean and variance of escape times. In contrast, strong coupling reduces the effective noise intensity to impede escape. Our results suggest that diffusive coupling among multistable elements contributes to regulating the rate of transitions among attracting states.

The Emergence of Specialized Roles Within Groups

Humans routinely form groups to achieve goals that no individual can accomplish alone. Group coordination often brings to mind synchrony and alignment, where all individuals do the same thing (e.g., driving on the right side of the road, marching in lockstep, or playing musical instruments on a regular beat). Yet, effective coordination also typically involves differentiation, where specialized roles emerge for different members (e.g., prep stations in a kitchen or positions on an athletic team). Role specialization poses a challenge for computational models of group coordination, which have largely focused on achieving synchrony. Here, we present the CARMI framework, which characterizes role specialization processes in terms of five core features that we hope will help guide future model development: Communication, Adaptation to feedback, Repulsion, Multi-level planning, and Intention modeling. Although there are many paths to role formation, we suggest that roles emerge when each agent in a group dynamically allocates their behavior toward a shared goal to complement what they expect others to do. In other words, coordination concerns beliefs (who will do what) rather than simple actions. We describe three related experimental paradigms-"Group Binary Search," "Battles of the Exes," and "Find the Unicorn"-that we have used to study differentiation processes in the lab, each emphasizing different aspects of the CARMI framework.

Human-robot facial coexpression

Large language models are enabling rapid progress in robotic verbal communication, but nonverbal communication is not keeping pace. Physical humanoid robots struggle to express and communicate using facial movement, relying primarily on voice. The challenge is twofold: First, the actuation of an expressively versatile robotic face is mechanically challenging. A second challenge is knowing what expression to generate so that the robot appears natural, timely, and genuine. Here, we propose that both barriers can be alleviated by training a robot to anticipate future facial expressions and execute them simultaneously with a human. Whereas delayed facial mimicry looks disingenuous, facial coexpression feels more genuine because it requires correct inference of the human's emotional state for timely execution. We found that a robot can learn to predict a forthcoming smile about 839 milliseconds before the human smiles and, using a learned inverse kinematic facial self-model, coexpress the smile simultaneously with the human. We demonstrated this ability using a robot face comprising 26 degrees of freedom. We believe that the ability to coexpress simultaneous facial expressions could improve human-robot interaction.

Implicit Rapport: Some Introductory Comments

"The relationship" is often cited as an essential aspect of successful psychotherapy, but what is it about the relationship that contributes to positive outcomes in treatment? This article introduces the concept of implicit rapport, which, in the parlance of social psychology, is an element of influence. Influence represents those things to which people respond without awareness of what exactly they are responding. Implicit rapport is here defined as a category of behaviors or interventions that occur within the context of clinical encounters and are designed or intended to promote a sense of feeling known, understood, valued, and safe. It is characterized as implicit because the variety of interactions referred to are not likely to be overtly or explicitly recognized by the client but, nonetheless, influences their willingness to commit to the work of psychotherapy. Clinical vignettes are presented to provide examples of how implicit rapport is conceptualized and actualized.

Interpersonal motor synchrony in autism: a systematic review and meta-analysis

Introduction

Interpersonal motor synchrony (IMS) is the spontaneous, voluntary, or instructed coordination of movements between interacting partners. Throughout the life cycle, it shapes social exchanges and interplays with intra- and inter-individual characteristics that may diverge in Autism Spectrum Disorder (ASD). Here we perform a systematic review and meta-analysis to summarize the extant literature and quantify the evidence about reduced IMS in dyads including at least one participant with a diagnosis of ASD.

Methods

Empirical evidence from sixteen experimental studies was systematically reviewed, encompassing spontaneous and instructed paradigms as well as a paucity of measures used to assess IMS. Of these, thirteen studies (n = 512 dyads) contributed measures of IMS with an in situ neurotypical partner (TD) for ASD and control groups, which could be used for meta-analyses.

Results

Reduced synchronization in ASD-TD dyads emerged from both the systematic review and meta-analyses, although both small and large effect sizes (i.e., Hedge's g) in favor of the control group are consistent with the data (Hedge's g = .85, p < 0.001, 95% CI[.35, 1.35], 95% PI[-.89, 2.60]).

Discussion

Uncertainty is discussed relative to the type of task, measures, and age range considered in each study. We further discuss that sharing similar experiences of the world might help to synchronize with one another. Future studies should not only assess whether reduced IMS is consistently observed in ASD-TD dyads and how this shapes social exchanges, but also explore whether and how ASD-ASD dyads synchronize during interpersonal exchanges.

High depressive symptomatology reduces emotional reactions to pictures of social interaction

Individuals with severe depressive symptoms present diminished facial expressions compared to healthy individuals. This reduced facial expression, which occurs in most depressive patients could impair social relationships. The current study sought to investigate whether pictures with social interaction cues could elicit different modulations of facial expressions and mood states in individuals with depressive symptoms compared to healthy individuals. A total of 85 individuals were divided into depressive and non-depressive groups based on their beck depression inventory scores. Participants viewed pictures containing neutral (objects), affiliative (people interacting socially), and control (people not interacting) scenes. Electromyographic signals were collected during the entire period of visualization of the blocks, and emotional questionnaires were evaluated after each block to assess sociability and altruism (prosocial states). In non-depressed individuals, affiliative pictures increased the activity of the zygomatic muscle compared to both neutral and control pictures and reduced fear of rejection compared to neutral pictures. During the visualization of the affiliative block, zygomatic major muscle activation was higher and fear of rejection was lower in the non-depressive individuals than in the depressive. These effects reflected the low expressions of smiling and sociability to affiliative pictures in depressive individuals. These findings highlight the importance of smiling and prosocial states in social interactions, especially in these individuals.

Mimicry in misophonia: A large-scale survey of prevalence and relationship with trigger sounds

BACKGROUND

Misophonia is often referred to as a disorder that is characterized by excessive negative emotional responses, including anger and anxiety, to "trigger sounds" which are typically day-to-day sounds, such as those generated from people eating, chewing, and breathing. Misophonia (literally "hatred of sounds") has commonly been understood within an auditory processing framework where sounds cause distress due to aberrant processing in the auditory and emotional systems of the brain. However, a recent proposal suggests that it is the perceived action (e.g., mouth movement in eating/chewing sounds as triggers) of the trigger person, and not the sounds per se, that drives the distress in misophonia. Since observation or listening to sounds of actions of others are known to prompt mimicry in perceivers, we hypothesized that mimicking the action of the trigger person may be prevalent in misophonia. Apart from a few case studies and anecdotal information, a relation between mimicking and misophonia has not been systematically evaluated.

METHOD

In this work, we addressed this limitation by collecting data on misophonia symptoms and mimicry behavior using online questionnaires from 676 participants.

RESULTS

Analysis of these data shows that (i) more than 45% of individuals with misophonia reported mimicry, indicating its wide prevalence, (ii) the tendency to mimic varies in direct proportion to misophonia severity, (iii) compared to other human and environmental sounds, trigger sounds of eating and chewing are more likely to trigger mimicking, and (iv) the act of mimicking provides some degree of relief from distress to people with misophonia.

CONCLUSION

This study shows prevalence of mimicry and its relation to misophonia severity and trigger types. The theoretical framework of misophonia needs to incorporate the phenomenon of mimicry and its effect on management of misophonia distress.

The Neural Mechanisms of Group Membership Effect on Emotional Mimicry: A Multimodal Study Combining Electromyography and Electroencephalography

Emotional mimicry plays a vital role in understanding others' emotions and has been found to be modulated by social contexts, especially group membership. However, the neural mechanisms underlying this modulation remain unclear. We explored whether and how group membership modulated emotional mimicry using a multimodal method combining facial electromyography (fEMG) and electroencephalography (EEG). We instructed participants to passively view dynamic emotional faces (happy vs. angry) of others (in-group vs. out-group) and simultaneously recorded their fEMG and EEG responses. Then, we conducted combined analyses of fEMG-EEG by splitting the EEG trials into two mimicry intensity categories (high-intensity mimicry vs. low-intensity mimicry) according to fEMG activity. The fEMG results confirmed the occurrence of emotional mimicry in the present study but failed to find a group membership effect. However, the EEG results showed that participants mimicked in-group happiness and anger more than out-group. Importantly, this in-group preference involved different neural mechanisms in happiness and anger mimicry. In-group preference for happiness mimicry occurred at multiple neural mechanisms such as N1 (at P7, Pz, and P8), P2 (at Pz and P8), N2 (at P8), and P3 (at P7, Pz, and P8); in-group preference for anger mimicry occurred at P1 (at P7) and P2 (at Pz). Our findings provide new neural evidence for the effect of group membership on emotional mimicry by uncovering the temporal dynamics of this effect.

Voluntary imitation of dynamic facial expressions in attention deficit hyperactivity disorder: a facial-behavior analysis

OBJECTIVE

The difficulties involved in social interaction among children with attention deficit hyperactivity disorder (ADHD) have been shown in many studies. Based on the knowledge that the imitation of facial expressions is a key factor in social interaction and functionality, the focus of prior studies has been on the evaluation of facial expressions in individuals with ADHD. However, little is known about voluntary facial mimicry in individuals with ADHD. In this context, we aimed to evaluate the voluntary-facial-imitation intensity of dynamic facial expressions in children with ADHD.

METHOD

Forty-one children with ADHD and 53 typically developing children were included in the study. Participants were presented with a video of six basic emotions and neutral facial expressions selected from the EU-Emotion Stimulus Set via a screen. After each emotion, the instruction "now imitate it" was given. While the children watched the video, their faces were recorded with a webcam. The intensity of the children's voluntary facial imitations was examined with a computer vision program (Openface) that performs facial analysis on recorded videos.

RESULTS

There was no significant difference between the groups in terms of facial emotion recognition accuracy. In group comparisons of voluntary facial mimicry, children with ADHD showed a significantly higher imitation intensity after emotional expressions of sadness, surprise and fear. There was no difference between the groups after the emotions of happiness, anger and disgust.

CONCLUSION

This non-obtrusive, noninvasive, and cost-effective method allowed us to measure the quantitative differences in facial mimicry between children with ADHD and typically developing children. Our results contribute new information to the literature by indicating which emotions can be used in the evaluation of social communication skills, as well as intervention targets for these skills, in children with ADHD.

Why We Gather: A New Look, Empirically Documented, at Émile Durkheim's Theory of Collective Assemblies and Collective Effervescence

For Durkheim, individuals' survival and well-being rest on cultural resources and social belonging that must be revived periodically in collective assemblies. Durkheim's concern was to clarify how these assemblies achieve this revitalization. An intensive examination of primitive religions led him to identify successive levels of engagement experienced by participants and to develop explanatory principles relevant to all types of collective gatherings. Durkheim's conception is widely referred to nowadays. However, the question of its empirical status remains open. We extracted from his text his main statements and translated them into research questions. We then examined each question in relation to current theories and findings. In particular, we relied on the plethora of recent cognitive and social-psychology studies that document conditions of reduced self-other differentiation. Abundant data support that each successive moment of collective assemblies contributes to blurring this differentiation. Ample support also exists that because shared emotions are increasingly amplified in collective context, they can fuel high-intensity experiences. Moreover, recent studies of self-transcendent emotions can account for the self-transformative effects described by Durkheim at the climax of collective assemblies. In conclusion, this century-old model is remarkably supported by recent results, mostly collected in experimental settings.

Language-Specific Constraints on Conversation: Evidence from Danish and Norwegian

Establishing and maintaining mutual understanding in everyday conversations is crucial. To do so, people employ a variety of conversational devices, such as backchannels, repair, and linguistic entrainment. Here, we explore whether the use of conversational devices might be influenced by cross-linguistic differences in the speakers' native language, comparing two matched languages-Danish and Norwegian-differing primarily in their sound structure, with Danish being more opaque, that is, less acoustically distinguished. Across systematically manipulated conversational contexts, we find that processes supporting mutual understanding in conversations vary with external constraints: across different contexts and, crucially, across languages. In accord with our predictions, linguistic entrainment was overall higher in Danish than in Norwegian, while backchannels and repairs presented a more nuanced pattern. These findings are compatible with the hypothesis that native speakers of Danish may compensate for its opaque sound structure by adopting a top-down strategy of building more conversational redundancy through entrainment, which also might reduce the need for repairs. These results suggest that linguistic differences might be met by systematic changes in language processing and use. This paves the way for further cross-linguistic investigations and critical assessment of the interplay between cultural and linguistic factors on the one hand and conversational dynamics on the other.

Some Evidence That Truth-Tellers Are More Attractive Than Liars

Despite the prevalence of deception, people rarely doubt others' sincerity. However, indirect evaluations of liars and truth-tellers may differ even in the absence of suspicion about veracity. Across three studies, we provide evidence for the truth attraction effect in two samples of target stimuli and three samples of participant judges. Target people are perceived as more attractive when telling the truth versus when they lie, an effect mediated by target warmth and openness. The truth attraction effect is stronger for female targets (vs. males); however, it is unaffected by the gender of the judge. Findings suggest people may be more likely to approach truth-tellers versus liars, even when not actively judging veracity. We discuss the challenges and benefits of treating both targets and participants as random factors in linear mixed-effect analyses and join the chorus of calls to increase the number of target stimuli in deception research.

A Shared Intentionality Account of Uniquely Human Social Bonding

Many mechanisms of social bonding are common to all primates, but humans seemingly have developed some that are unique to the species. These involve various kinds of interactive experiences-from taking a walk together to having a conversation-whose common feature is the triadic sharing of experience. Current theories of social bonding have no explanation for why humans should have these unique bonding mechanisms. Here we propose a shared intentionality account of uniquely human social bonding. Humans evolved to participate with others in unique forms of cooperative and communicative activities that both depend on and create shared experience. Sharing experience in these activities causes partners to feel closer because it allows them to assess their partner's cooperative competence and motivation toward them and because the shared representations created during such interactions make subsequent cooperative interactions easier and more effective.

Audience synchronies in live concerts illustrate the embodiment of music experience

A study of 132 audience members of three classical public concerts (all three staged the same chamber music pieces by Ludwig van Beethoven, Brett Dean, and Johannes Brahms) had the goal of analyzing the physiological and motor responses of audiences. It was assumed that the music would induce synchronous physiology and movement in listeners (induction synchrony). In addition to hypothesizing that such synchronies would be present, we expected that they were linked to participants' aesthetic experiences, their affect and personality traits, which were assessed by questionnaires before and after the concerts. Clear evidence was found of physiological synchrony (heart rate, respiration rate, skin conductance response) as well as movement synchrony of the audiences, whereas breathing behavior was not synchronized. Thus the audiences of the three concerts resonated with the music, their music perception was embodied. There were links between the bodily synchrony and aesthetic experiences: synchrony, especially heart-rate synchrony, was higher when listeners felt moved emotionally and inspired by a piece, and were immersed in the music. Personality traits were also associated with the individual contributions to induction synchrony.

From distal to proximal to interactive: behavioral and brain synchrony during attraction, courtship, and sexual interaction-implications for clinical assessments of relationship style and quality

INTRODUCTION

Synchronous behaviors between individuals are nonverbal signs of closeness and common purpose. In the flow from initial attraction to intimate sexual interaction, attention and synchrony move from distal to proximal to interactive and are mediated by sensitized activation of neural systems for sexual motivation, arousal, and desire and those that recognize and mimic common facial and body movements between individuals. When reinforced by sexual pleasure and other relationship rewards, this results in the strengthening of attraction and bonding and the display of more common motor patterns. As relationships falter, nonverbal behaviors likely become asynchronous.

OBJECTIVES

To define behavioral, romantic, and sexual synchrony during phases of attraction and how their disruption can be observed and utilized by clinicians to assess individual relationship styles and quality.

METHODS

We review the literature on behavioral and attentional synchrony in humans and animals in an effort to understand experiential and innate mechanisms of synchrony and asynchrony and how they develop, as well as implications for attraction, relationship initiation, maintenance of romantic and sexual closeness, and relationship disintegration.

RESULTS

Evidence is presented that behavioral synchrony and the neural mechanisms that underlie it are vital to relationship formation and satisfaction.

CONCLUSION

Behavioral synchrony helps to create feelings of sexual and romantic synergy, cohesion, and arousal among individuals. Asynchrony is aversive and can spark feelings of discontent, aversion, and jealousy. Thus, observing patterns of nonverbal sexual and romantic synchrony between individuals offers insights into the potential quality of their relationships.

Differentiated, rather than shared, strategies for time-coordinated action in social and non-social domains in autistic individuals

Autism spectrum disorder (ASD) is a neurodevelopmental condition with a highly heterogeneous adult phenotype that includes social and non-social behavioral characteristics. The link between the characteristics assignable to the different domains remains unresolved. One possibility is that social and non-social behaviors in autism are modulated by a common underlying deficit. However, here we report evidence supporting an alternative concept that is individual-centered rather than deficit-centered. Individuals are assumed to have a distinctive style in the strategies they adopt to perform social and non-social tasks with these styles presumably being structured differently between autistic individuals and typically-developed (TD) individuals. We tested this hypothesis for the execution of time-coordinated (synchronized) actions. Participants performed (i) a social task that required synchronized gaze and pointing actions to interact with another person, and (ii) a non-social task that required finger-tapping actions synchronized to periodic stimuli at different time-scales and sensory modalities. In both tasks, synchronization behavior differed between ASD and TD groups. However, a principal component analysis of individual behaviors across tasks revealed associations between social and non-social features for the TD persons but such cross-domain associations were strikingly absent for autistic individuals. The highly differentiated strategies between domains in ASD are inconsistent with a general synchronization deficit and instead highlight the individualized developmental heterogeneity in the acquisition of domain-specific behaviors. We propose a cognitive model to help disentangle individual-centered from deficit-centered effects in other domains. Our findings reinforce the importance to identify individually differentiated phenotypes to personalize autism therapies.

Relationships between the race implicit association test and other measures of implicit and explicit social cognition

Background

The race-based Implicit Association Test (IAT) was proposed to measure individual differences in implicit racial bias subsumed within social cognition. In recent years, researchers have debated the theoretical tenets underpinning the IAT, questioning whether performance on this task: (1) measures implicit attitudes that operate automatically outside of conscious awareness; (2) reflects individual differences in social cognition; and (3) can predict social behavior. One way to better address these research questions is to assess whether the race-IAT correlates with other implicit processes that are subsumed within social cognition.

Aims

The current study assessed whether the race-IAT was related to other commonly used individual difference measures of implicit (and explicit) social cognition. Experiment 1 assessed whether dissociable patterns of performance on the race-IAT were related to measures of implicit imitative tendencies, emotion recognition and perspective taking toward White task actors, as well as explicit measures of trait and state affective empathy and racial bias. Overcoming limitations of task conceptual correspondence, Experiment 2 assessed whether these latter tasks were sensitive in detecting racial biases by using both White and Black task actors and again examined their relationships with the race-IAT.

Method

In two lab-based experiments, 226 and 237 participants completed the race-IAT followed by an extensive battery of social cognition measures.

Results

Across both experiments, pro-White/anti-Black bias on the race-IAT was positively related to a pro-White bias on explicit measures of positive affective empathy. However, relationships between the race-IAT and implicit imitative tendencies, perspective taking, emotion recognition, and explicit trait and negative state affective empathy were statistically equivalent.

Conclusion

The race-IAT was consistently related to explicit measures of positive state affective empathy but not to other individual difference measures of implicit social cognition. These findings are discussed with regards to the theoretical underpinnings of the race-IAT as an individual difference measure of implicit social cognition, as well as alternative explanations relating to the reliability of social cognition measures and the various combinations of general-purpose (social and non-social) executive processes that underpin performance on these tasks.

Face2face: advancing the science of social interaction

Face-to-face interaction is core to human sociality and its evolution, and provides the environment in which most of human communication occurs. Research into the full complexities that define face-to-face interaction requires a multi-disciplinary, multi-level approach, illuminating from different perspectives how we and other species interact. This special issue showcases a wide range of approaches, bringing together detailed studies of naturalistic social-interactional behaviour with larger scale analyses for generalization, and investigations of socially contextualized cognitive and neural processes that underpin the behaviour we observe. We suggest that this integrative approach will allow us to propel forwards the science of face-to-face interaction by leading us to new paradigms and novel, more ecologically grounded and comprehensive insights into how we interact with one another and with artificial agents, how differences in psychological profiles might affect interaction, and how the capacity to socially interact develops and has evolved in the human and other species. This theme issue makes a first step into this direction, with the aim to break down disciplinary boundaries and emphasizing the value of illuminating the many facets of face-to-face interaction. This article is part of a discussion meeting issue 'Face2face: advancing the science of social interaction'.

Does the threat of COVID-19 modulate automatic imitation?

The tendency to involuntarily imitate the actions of others (automatic imitation) can be modulated by social affiliative cues. Here, we explored whether the disruption to our social lives caused by the COVID-19 pandemic may subsequently influence automatic imitation. Three groups were initially presented a sentence comprehension task that featured either neutral (control), safe or unsafe primes to COVID-19 infection. They then completed an automatic imitation task, where a numeric cue was presented alongside apparent motion of an index or middle finger, which was either compatible or incompatible with the required response. Reaction times were longer for the incompatible compared to compatible trials, and thus demonstrated automatic imitation. However, there was no influence of the primes indicating that automatic imitation was unaffected by the risk of COVID-19. The potential theoretical explanations and practical implications of pathogen avoidance and social bonding incentives are discussed with reference to pandemic events.

Adolescent borderline personality traits and dyadic behavior shape mother-adolescent cortisol synchrony

BACKGROUND

Associations between parent and child cortisol levels ("cortisol synchrony") are often reported and positive synchrony may mark dyadic regulation on a physiological level. Although dyadic behavior during interaction and adolescent borderline personality disorder (BPD) traits are linked with individual and dyadic regulatory capacities, little is known about how both factors influence parent-adolescent cortisol synchrony. We hypothesized that cortisol synchrony would differ depending on behavioral synchrony, i.e., smooth reciprocal dyadic interaction patterns, adolescent BPD traits, and their interactions.

METHODS

Multilevel state-trait modeling was implemented to investigate associations between concurrent mother-adolescent state cortisol and mother-adolescent average cortisol levels in a community sample of 76 mother-adolescent dyads. Three saliva samples were collected across interaction paradigms. Behavioral synchrony was observed, and adolescent BPD traits were evaluated using clinical interviews.

RESULTS

First, behavioral synchrony and absence of BPD traits were linked with positive associations between adolescent and maternal state cortisol (positive synchrony), BPD traits with negative associations (negative synchrony). When interaction effects were examined, results were more nuanced. In low-risk dyads (higher behavioral synchrony, no BPD traits) asynchrony was found. When risk (BPD traits) and resource (higher behavioral synchrony) were combined, synchrony was positive. Lastly, in high-risk dyads (lower behavioral synchrony, adolescent BPD traits), negative synchrony was observed. Average adolescent and maternal cortisol levels were consistently positively associated in dyads with higher risk.

CONCLUSIONS

Positive dyadic interaction patterns are associated with positive state cortisol synchrony in mother-adolescent dyads and could buffer the effect of BPD traits, possibly supporting the process of physiological regulation.

Young children use imitation communicatively

There is growing evidence that children imitate not just to learn from others but also to affiliate socially with them. However, although imitation can convey a wealth of affiliative information to others, it is not yet known whether imitators intend for this to be the case. In particular, we do not know whether children imitate communicatively in some contexts, expending extra effort to make sure that the demonstrator sees their imitation. Here, in two experiments (N = 20 and N = 48, respectively), we tested whether preschool-age children modify their imitation when needed to ensure that the demonstrator sees it. In each trial, children were shown a demonstration. Then, for their response, in one condition a barrier obscured the demonstrator's view of children's imitation unless children raised their arms above the barrier while imitating. In the other condition the demonstrator was able to see children's imitation without any additional effort from children. Results from both experiments showed that children were significantly more likely to imitate with their arms raised when their actions would otherwise be obscured from view. In the second experiment, we also coded for other communicative behaviors (e.g., social smiles, eye contact, showing gestures) and found that children often displayed communicative behaviors while imitating, as expected, in both conditions. Thus, young children actively use imitation communicatively in some contexts.

Only empathy-related traits, not being mimicked or endorphin release, influence social closeness and prosocial behavior

Seminal studies suggest that being mimicked increases experienced social closeness and prosocial behavior to a mimicking confederate (i.e., interaction partner). Here we reexamine these results by considering the role of empathy-related traits, an indirect proxy for endorphin uptake, and their combined effects as an explanation for these results. 180 female participants were mimicked or anti-mimicked in an interaction with a confederate. The effects of being mimicked versus anti-mimicked in relation to empathy-related traits and endorphin release (assessed indirectly via pain tolerance) on experienced closeness and prosocial behavior were assessed using Bayesian analyses. Our results suggest that high individual empathy-related traits increase social closeness to the anti-mimicking and mimicking confederate and to one's romantic partner, as compared to mimicry alone. Results furthermore strongly suggest that high individual empathy-related traits increase prosocial behavior (donations and willingness to help) as compared to mimicry alone. These findings extend previous work by highlighting that empathy-related traits are more influential in creating positive effects on social closeness and prosocial behavior than a one-shot mimicking encounter.

Social Isolation Affects the Mimicry Response in the Use of Smartphones : An Ethological Experiment during the COVID-19 Pandemic

Humans are social animals that rely on different ways to interact with each other. The COVID-19 pandemic strongly changed our communication strategies. Because of the importance of direct contact for our species, we predict that immediately after the forced social isolation, people were more prone to engage in direct rather than in virtual interactions, thus showing a lower mimicry response in the use of smartphones. In a non-longitudinal study, we collected behavioral data under naturalistic contexts and directly compared the data of the mimicry response gathered immediately following the Italian lockdown (May-September 2020) with those gathered one year later (May-October 2021). Contrary to our expectations, the mimicry response in the use of smartphones was higher immediately after the lockdown than a year later. Probably the large use of these devices during the lockdown translated into a greater sensitivity to be affected by others' smartphone manipulation. Indeed, social isolation modified, at least in the short term, the ways we interact with others by making us more prone to engage in "virtual" social interactions. The bright side of the coin unveiled by our findings is that the effect seems to diminish over time. The large behavioral dataset analyzed here (1,608 events; 248 people) also revealed that the mimicry response in the use of smartphones was higher between familiar subjects than between strangers. In this view, mimicry in manipulating smartphones can be considered an example of joint action that fosters behavioral synchrony between individuals that, in the long-term, can translate into the formation of social bonding.

Establishing conversational engagement and being effective: The role of body movement in mediated communication

A model for investigating the effects of body movement on conversational effectiveness in computer-mediated communication (CMC) is developed based on theories of motor cognition and embodiment. Movement is relevant to a wide range of CMC settings, including remote interviews, court testimonials, instructing, medical consultation, and socializing. The present work allows for a consideration of different forms of motoric activation, including gesturing and full-body motion, in mediated conversational settings and the derivation of a range of testable hypothesis. Motor cognition and embodiment provide an account of how speaker and listener become subject to the consequences of the muscular activation patterns that come with body movement. While movement supports internal elaboration, thus helping the speaker in formulating messages, it also has direct effects on the listener through behavioral synchrony and motor contagion. The effects of movement in CMC environments depend on two general characteristics: the level of visibility of movement and the extent to which the technology facilitates or inhibits movement. Available channels, set-up of technology, and further customization therefore determine whether movement can fulfil its internal functions (relevant to cognitive-affective elaboration of what is being said by the speaker) and its external functions (relevant to what is being perceived by and activated within the listener). Several indicators of conversational effectiveness are identified that serve as outcome variables. This MCEE model is intended to help users, developers and service provides to make CMC more engaging and more meaningful.

Interpersonal synchronization of spontaneously generated body movements

Interpersonal movement synchrony (IMS) is central to social behavior in several species. In humans, IMS is typically studied using structured tasks requiring participants to produce specific body movements. Instead, spontaneously generated (i.e., not instructed) movements have received less attention. To test whether spontaneous movements synchronize interpersonally, we recorded full-body kinematics from dyads of participants who were only asked to sit face-to-face and to look at each other. We manipulated interpersonal (i) visual contact and (ii) spatial proximity. We found that spontaneous movements synchronized across participants only when they could see each other and regardless of interpersonal spatial proximity. This synchronization emerged very rapidly and did not selectively entail homologous body parts (as in mimicry); rather, the synchrony generalized to nearly all possible combinations of body parts. Hence, spontaneous behavior alone can lead to IMS. More generally, our results highlight that IMS can be studied under natural and unconstrained conditions.

Mimicry and affective disorders

Mimicry, the spontaneous imitation of an interaction partner, is an important part of everyday communication, as it has been shown to foster relationships and increase closeness. People with affective disorders often have problems in their interpersonal lives. In this review, we pursue the question if these problems are linked to differences in mimicry behavior. First, we summarize existing evidence on mimicry, depression and mood. Then, based on five theories differing in their core assumptions regarding mechanisms and functionality of mimicry, we derive suggestions on how mimicry might affect people suffering from bipolar disorders, dysthymia or depression. Depending on each theory, a different understanding of affective disorders and mimicry arises, and we show how the evidence fit in with the suggested theories. Previous studies on affective disorders have focused on mimicry behavior of participants watching photos, computer-generated images, or short video sequences. This review sheds light on the fact that evidence on mimicry needs to be broadened systematically for people with affective disorders in interactional settings. Mimicry represents a novel and important yet underestimated source for diagnostic, intervention and evaluation processes in affective disorders.

Smaller preferred interpersonal distance for joint versus parallel action

During social interaction, humans prefer to keep a certain distance between themselves and other individuals. This preferred 'interpersonal distance' (IPD) is known to be sensitive to social context, and in the present study we aimed to further investigate the extent to which IPD is affected by the specific type of social interaction. In particular, we focused on the contrast between joint actions, where two or more individuals coordinate their actions in space and time to achieve a shared goal, and parallel actions, where individuals act alongside each other but individually. We predicted that joint action would be associated with a smaller preferred IPD compared to parallel action. Additionally, given that this research took place in the midst of the COVID-19 pandemic, we aimed to assess whether IPD preferences are affected by individuals' concerns about infection in general, as well as COVID-19 in particular. We predicted that higher individual concerns would be associated with greater preferred IPD. To test these hypotheses, we asked participants to imagine different social scenarios (involving either joint or parallel actions alongside a stranger) and indicate, on a visual scale, their preferred IPD. The results of two experiments (n = 211, n = 212) showed that participants preferred a shorter distance when they imagined acting jointly compared to when they imagined acting in parallel. Moreover, participants who reported higher discomfort for potential pathogen contact and who were more aware of the COVID-19 context in which the study took place preferred a larger IPD in general. Our results provide further evidence that different types of social interaction shape IPD preference. We discuss potential reasons for this phenomenon and highlight remaining questions for future research.

When Groups of Different Sizes Collide: Effects of Targeted Verbal Aggression on Intragroup Functioning

When competing for scarce resources, groups can behave aggressively toward one another. Realistic conflict theory suggests that intergroup hostility internally ties groups together, thus improving intragroup functioning. In contrast, conflict spillover theory suggests that aggressive behaviors between groups can permeate to the intragroup level and thus worsen intragroup functioning. We reconcile these two opposite perspectives by introducing the relative group size as a moderator that determines when and how targeted verbal aggression from one group harms or improves intragroup functioning in the targeted group. We tested our hypotheses using a sample of in-situ observations of transcribed plenary discussions in the German national parliament and compared intergroup targeted verbal aggression by distinguishing targeted verbal aggression from two social groups (i.e., a new populist smaller party vs. a larger group of veteran parliament members). We measured targeted verbal aggression as a form of hostile intergroup behavior from each social group using computerized text analyses. We analyzed intragroup functioning using a measure of verbal mimicry. Our results show support for our hypotheses. We discuss theoretical and practical implications for the verbal aggression and intergroup relations literature.