Infant Temperament Is Associated With Milk Cortisol but Not With Maternal Childhood Trauma

Previous studies have suggested that maternal childhood trauma (MCT) may influence infant temperament, but the underlying physiological mechanisms remain unclear. This study sought to confirm the involvement of breast milk cortisol in the link between MCT and infant temperament. The study sample included 90 mother-infant dyads recruited from the urban Polish population. MCT was assessed based on the Early Life Stress Questionnaire (ELSQ) and infant temperamental factors (surgency/extraversion, negative affectivity, and orienting/regulation) using the Infant Behavior Questionnaire-Revised at 12 months of life. Cortisol was assayed in milk samples collected at 5 months of life using the ELISA method. Based on the ELSQ median, the sample was divided into low and high MCT groups. The ANCOVA models with milk cortisol as a covariant were run to check the effect of low versus high MCT on infant temperament. We found a positive association between milk cortisol and orienting/regulation. Surprisingly, the low and high MCT groups did not significantly differ in milk cortisol. Furthermore, we found that MCT was unrelated to any infant temperamental factor. While recent literature on the association between milk cortisol and infant temperament is inconsistent, our results suggest that high orienting/regulation might be an adaptation to adverse environments such as stress. Moreover, the infant's temperament appears to be more responsive to the current exposition to maternal stress than her experience of traumatic stress.

Anatomical and functional basis of facial expressions and their relationship with emotions in horses

An emotion is defined as the affective response to a stimulus that leads to specific bodily changes, enabling individuals to react to positive or negative environmental conditions. In the absence of speech, emotions in animals are primarily studied by observing expressive components, such as facial expressions. This review aims to analyze the available literature on the influence of environmental stimuli on measurable behaviors in horses, describing the anatomical components involved in perception at the central nervous system level and the efferent pathways that trigger facial muscle contraction or relaxation, thus altering facial expressions. Additionally, articles addressing the function of facial expressions in communication are discussed, emphasizing their role in social interactions in this species. While there is limited research on equine neurophysiology, considering the common structure of the limbic system in most mammals, studies conducted on canines and primates were taken into account. In conclusion, the article underscores the importance of understanding equine facial expressions to assess their emotional states and, by extension, their welfare.

Beware! Different methods lead to divergent results on yawn contagion modulation in bonobos

Contagious yawning (CY)-linked to physiological synchronization and possibly emotional contagion-occurs when one individual's yawn induces yawning in others. CY was investigated over different time windows (minutes from the triggering stimulus) via naturalistic or experimental studies (using real and video yawns, respectively) with contrasting results, especially in bonobos. We verified whether in bonobos result divergences may derive from different methods. We gathered yawning data on 13 bonobos at Twycross Zoo (UK) via a naturalistic (all-occurrences observations) and experimental approach (by showing yawn/control video stimuli). Based on literature, we used 1- and 3-min windows to detect CY. Due to fission-fusion management, individuals could form permanent or non-permanent associations (more/less familiar subjects under naturalistic setting). Video yawn stimuli may come from group mates/stranger models (more/less familiar subjects under the experimental setting). Stimulus type and time window affected CY modulating factors but not CY detection. Familiarity and age effect on CY showed opposite trends in 3-min trials and 1-min observations. CY was highest in oldest, non-permanently (rather than permanently) associated subjects in the naturalistic setting, but in the youngest subjects and with ingroup (rather than outgroup) models in trials. The age effect differences on CY might be due to decontextualized yawns and immature subject curiosity toward videos. The reversed familiarity effect suggests CY's context-dependent function in promoting social synchronization with socially distant group mates, as failing to coordinate as a group may lead to social disruption. Complementary methods are needed to fully understand motor replication phenomena.

Being facially expressive is socially advantageous

Individuals vary in how they move their faces in everyday social interactions. In a first large-scale study, we measured variation in dynamic facial behaviour during social interaction and examined dyadic outcomes and impression formation. In Study 1, we recorded semi-structured video calls with 52 participants interacting with a confederate across various everyday contexts. Video clips were rated by 176 independent participants. In Study 2, we examined video calls of 1315 participants engaging in unstructured video-call interactions. Facial expressivity indices were extracted using automated Facial Action Coding Scheme analysis and measures of personality and partner impressions were obtained by self-report. Facial expressivity varied considerably across participants, but little across contexts, social partners or time. In Study 1, more facially expressive participants were more well-liked, agreeable, and successful at negotiating (if also more agreeable). Participants who were more facially competent, readable, and perceived as readable were also more well-liked. In Study 2, we replicated the findings that facial expressivity was associated with agreeableness and liking by their social partner, and additionally found it to be associated with extraversion and neuroticism. Findings suggest that facial behaviour is a stable individual difference that proffers social advantages, pointing towards an affiliative, adaptive function.

The psychology of Mona Lisa's smile

Mona Lisa's ambiguous expression, oscillating between melancholy and contentment, has captivated viewers for centuries, prompting diverse explanations. This article proposes a novel interpretation grounded in the psychological theory of perceptual organisation. Central to the investigation is the "Ambiguity-Nuance", a subtly shaded, blended region framing the upper part of the lips, hypothesised to influence perceived expression due to perceptual organization. Through carefully crafted artwork and systematic manipulations of Mona Lisa reproductions, experiments reveal how alterations in the perceptual relationships of the Ambiguity-Nuance yield significant shifts in perceived expression, explaining why Mona Lisa's appearance changes and under which conditions she looks content versus melancholic based on perceptual organization. These findings underscore the pivotal role of psychological principles in shaping ambiguous expressions in the Mona Lisa, and extend to other Leonardo's portraits, namely La Bella Principessa and Scapigliata. This study sheds light on the intersection of psychology and art, offering new perspectives on timeless masterpieces.

The long-term impact of early adverse experience on adaptive functioning: a pilot study integrating measures of mental status, nonverbal communication, and heart rate variability

Background: Childhood maltreatment (CM) can disrupt the development of behavioural and physiological systems, increasing the risk of physical and psychological adverse outcomes across the lifespan. CM may cause interpersonal dysfunctions that impair social communication and lead to dysfunctional activation of the autonomic nervous system. The present exploratory study analyzed the long-term impact of CM from an integrated perspective through the simultaneous assessment of psychological symptoms, social and behavioural communication, and physiological regulation.

Methods: Participants were 55 healthy university students (9 males and 46 females; mean age ± SD = 25.26 ± 2.83 years), who filled out a battery of questionnaires to assess the presence of CM (Childhood Trauma Questionnaire) and psychopathological symptoms (Symptom Check-List-90 Item Revised). Participants were then subjected to a videotaped interview for the assessment of non-verbal behaviour (Ethological Coding System for Interviews) and measurement of tonic heart rate variability (HRV), a measure of physiological adaptability to the environment. We performed Pearson's correlation analysis to evaluate the associations between non-verbal behaviour, HRV, and CM variables. Multiple regression analysis was used to evaluate the independent associations between CM variables on HRV and nonverbal behaviour.

Results: We found an association between more severe CM, increased symptoms-related distress (ps < .001), less submissive behaviour (ps < .018), and decreased tonic HRV (ps < .028). As a result of multiple regression analysis, participants with a history of emotional abuse (R² = .18, p = .002) and neglect (R² = .10, p = .03) were more likely to display decreased submissive behaviour during the dyadic interview. Moreover, early experience of emotional (R² = .21, p = .005) and sexual abuse (R² = .14, p = .04) was associated with decreased tonic HRV.

Conclusion: Our preliminary findings show the utility of analyzing the long-term effects of adverse early experiences at different levels of ‘adaptive functioning’ (the capabilities needed to respond effectively to environmental demands).

Substantial traumatic experiences during childhood, such as emotional abuse, emotional neglect, and sexual abuse were associated with lower heart rate variability levels in a sample of young adults.

Young adults with a history of emotional abuse and neglect were more likely to display decreased submissive behaviour (ethological behaviour) during the dyadic interview.

Severe childhood maltreatment was associated with increased symptoms-related distress, less submissive behaviour (ethological behaviour), and decreased tonic heart rate variability in young adults.

Perceptual Phenomena Cannot Be Approached from a Single Perspective

This article explores the relationship between neurophysiology and phenomenology in the context of ambiguous figures. Divided into three parts, the study investigates new forms of stimulus and experience errors that arise from ambiguous figures. Part 1 discusses the limitations of a single-disciplinary approach and cautions against relying only on neurophysiological explanations for perceptions. A sole reliance on neurophysiological explanations can lead to stimulus and experience errors, as well as to the development of an unfounded mind/body dualism. Part 2 focusses on the stimulus error associated with ambiguous figures. It also shows how the Mona Lisa's ambiguous expression can cause the experience error. Unlike other forms of ambiguous figures, different expressions of Mona Lisa are perceived when seen in different definitions. It is shown how assigning a higher ontological status to one of the expressions because it aligns with our knowledge of the nervous system, as conjectured by some authors, gives rise to the experience error. Part 3 emphasises the importance of complementing neurophysiological interpretations with phenomenological ones for a better understanding of perceptual phenomena. Phenomenology provides constraints and corrections to neurophysiology, whereas neurophysiology informs phenomenology through empirical findings. The theory of levels of reality is introduced as a framework to underlie the connections and dependencies between different perspectives. Using both neurophysiological and phenomenological approaches, a comprehensive understanding of perceptual phenomena emerges, surpassing the limitations of each discipline. This method encourages a holistic view of perception, where neurophysiology and phenomenology coexist, complementing and enriching each other's insights.

Histomorphological analysis of the superficial musculoaponeurotic system in Macaca mulatta species

INTRODUCTION

The superficial musculoaponeurotic system (SMAS) is a well described facial functional unit in humans. SMAS connects mimic musculature to the skin having many implication in facial mimic expression. One of the various morphological and physiological analogies in human and Macaca mulatta species is the facial mimic. The present study analyzed Macaca mulatta species SMAS morphology and its facial topographical differences and compared this with human SMAS tissue morphology.

MATERIAL AND METHODS

Macaca mulatta full-graft tissue blocks of skin, subcutaneous tissue and mimic muscles from five topographical different facial regions (Regio Temporalis, Regio Buccalis, Regio Infraorbitalis, Regio Angulus Oris and Regio Mandibularis) were collected postmortem from eight individuals (n = 8) at the German Primate Center, Leibniz Institute for Primate Research in Göttingen (DPZ) and studied histologically. Haematoxylin-eosin and azan stained histological serial sections of full-graft tissue blocks were analyzed and SMAS topographical differences evaluated.

RESULTS

SMAS typical tissue morphology was recognized in all Macaca mulatta histological serial sections (n = 780). Regio Infraorbitalis Macaca mulatta SMAS (MmSMAS) morphology was similar to human infraorbital SMAS morphology (type I SMAS). Suborbicularis oculi fat pad was recognized in Macaca mulatta samples. Human type I similar SMAS morphology was demonstrated over Macaca mulatta Regio Temporalis and Regio Buccalis. Regio Angulus Oris and the cranial area of the Regio Mandibularis presented human type II similar SMAS morphology. Type IV MmSMAS was closely related to the parotid gland tissue presence. The cervical area of the Regio Mandibularis presented human type V similar SMAS morphology.

CONCLUSIONS

SMAS is a complex fibro-musculo-adipose tissue network and probably an important pivot in Macaca mulatta facial system supporting mimic expression. This study provided insights into MmSMAS typology and similarity with human SMAS tissue morphology.

"Untying the knot": The primitive orofacial muscle architecture in the gorilla (Gorilla gorilla) as a key to the evolution of hominin facial movement

The anatomical underpinnings of primate facial expressions are essential to exploring their evolution. Traditionally, it has been accepted that the primate face exhibits a "scala natura" morphocline, ranging from primitive to derived characteristics. At the primitive end, the face consists of undifferentiated muscular sheets, while at the derived end there is greater complexity with more muscles and insertion points. Among these, the role of the human modiolus ("knoten" in German) has been emphasized. Recent studies have challenged this view by revealing significant complexity in the faces of several non-human primates, thereby rejecting the linear notion of facial evolution. However, our knowledge of the facial architecture in gorillas, the second closest living relatives to modern humans, remains a significant gap in the literature. Here, we present new findings based on dissection and histological analysis of one gorilla craniofacial specimen, alongside 30 human hemifaces. Our results indicate that while the number and overall arrangement of facial muscles in the gorilla are comparable to those of chimpanzees and modern humans, several orofacial features distinguish the gorilla's anatomy from that of hominins. Among these are the absence of a modiolus, the continuity of muscular fibers over the region of the mouth corner, the flat (uncurving) sheet of the orbicularis oris muscle, and the insertion of direct labial tractors both anterior and posterior to it. Collectively, the anatomical characteristics observed in the gorilla suggest that the complex anatomy of the hominin face should be considered synapomorphic (shared-derived) within the Pan-Homo clade.

Unravelling the relation between altruistic cooperativeness trait, smiles, and cooperation: a mediation analysis

Introduction

Human cooperativeness is an important personality trait. However, the mechanism through which people cooperate remains unclear. Previous research suggests that one of the proposed functions of smiling is to advertise altruistic dispositions, leading to successful cooperation. In particular, studies have reported that Duchenne smiles are honest signals of cooperative intent because they are not easy to produce voluntarily. This study aimed to examine the predictive relationships among altruistic cooperativeness traits, Duchenne smiles, and cooperative behavior.

Methods

A total of 90 people were randomly assigned to dyads and filmed while they participated in a ten-minute, unstructured conversation followed by a prisoner's dilemma game to measure their cooperative behaviors. Their smiles during conversations were classified as Duchenne or non-Duchenne. Participants' altruistic dispositions were measured before the conversation began using an anonymous prisoner's dilemma game.

Results

The results of our linear regression analyses support previous findings that individual's Duchenne smiles and their own cooperative behavior are positively correlated. However, when we controlled for altruistic cooperativeness, Duchenne smiles no longer correlated with cooperative behavior. The results of the mediation analyses showed that Duchenne smiles and smile synchrony did not mediate the predictive relationship between altruistic cooperativeness and cooperative behavior.

Discussion

Our results suggest that human cooperative behavior may be predetermined by altruistic cooperativeness. This calls for the reconsideration of the Duchenne smile as an underlying behavioral mechanism that is effective for signaling altruistic cooperative intent.

Positive communication workshops: are they useful for treatment programmes for anorexia nervosa?

Background

Social isolation, loneliness and difficulties in relationships are often described as a core feature of eating disorders. Based on the experimental research, we have designed one-off workshops for patients in inpatients and day care services and evaluated its acceptability and effectiveness using feedback questionnaires.

Methods

This naturalistic project is an evaluation of multiple positive communication workshops. Forty-one participants completed workshop questionnaires, which were provided immediately at the beginning and end of the workshop, including feedback on these one-off groups. The workshops consisted of educational and experiential components. The questionnaire outcomes were evaluated by independent researchers.

Results

All participants were female adults with a mean age of 33 (12.2) and a diagnosis of Anorexia Nervosa (AN; either restrictive or binge-purge subtype). Post-workshop questionnaires showed large effect sizes in the improvement of understanding the importance and confidence in using positive communication strategies.

Discussion

Addressing social communication difficulties in eating disorder treatment programmes adds valuable dimensions to these symptom-based treatments in both inpatient settings and day services, and may provide broader benefits in overall social functioning in patients with AN.

Conclusion

Brief one-off workshops targeting social functioning for patients with eating disorders might be useful complementary input for treatment programmes.

Axonal mapping of the motor cranial nerves

Basic behaviors, such as swallowing, speech, and emotional expressions are the result of a highly coordinated interplay between multiple muscles of the head. Control mechanisms of such highly tuned movements remain poorly understood. Here, we investigated the neural components responsible for motor control of the facial, masticatory, and tongue muscles in humans using specific molecular markers (ChAT, MBP, NF, TH). Our findings showed that a higher number of motor axonal population is responsible for facial expressions and tongue movements, compared to muscles in the upper extremity. Sensory axons appear to be responsible for neural feedback from cutaneous mechanoreceptors to control the movement of facial muscles and the tongue. The newly discovered sympathetic axonal population in the facial nerve is hypothesized to be responsible for involuntary control of the muscle tone. These findings shed light on the pivotal role of high efferent input and rich somatosensory feedback in neuromuscular control of finely adjusted cranial systems.

Selective Neurectomy for Treatment of Post-Facial Paralysis Synkinesis: A Systematic Review

BACKGROUND

 Synkinesis is commonly encountered after flaccid facial paralysis and can have a detrimental impact on a patient's life. First-line treatment of synkinesis is chemodenervation with botulinum toxin (Botox) and neuromuscular retraining. Surgical options include selective myectomy, selective neurectomy (SN), cross-facial nerve grafting, nerve substitution, and free gracilis muscle transfer. Data on surgical management of synkinesis using SN is limited.

EVIDENCE REVIEW

 PubMed, Embase, Cochrane CENTRAL, Cochrane Neuromuscular Register, Clinicaltrials.gov, and World Health Organization International Clinical Trials Registry Platform were searched using a comprehensive keyword strategy in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All English-only texts published in the past 20 years were included. Two independent investigators reviewed 906 abstracts and 7 studies met inclusion criteria. Demographics, etiology of paralysis, time to surgery, and primary outcomes studied were collected.

FINDINGS

 A total of 250 patients were included across 7 studies. In 6 out of 7 studies, Botox was used prior to surgical intervention. Two studies showed significant reduction in Botox dosage postoperatively, while one study showed no difference. Other primary outcomes included the House-Brackmann Score, palpebral fissure width, electronic clinician-graded facial function scale (eFACE) score, Facial Clinimetric Evaluation (FaCE) scale, and Synkinesis Assessment Questionnaire (SAQ). Three studies showed significant improvement in the eFACE score, two studies showed significant improvement in the FaCE scale, while one study showed improvement in quality of life measured by the SAQ.

CONCLUSION

 SN can be considered as an adjunct to other management options including neuromuscular retraining, Botox, selective myectomy, and reanimation procedures. While there is great heterogeneity of study design in the studies included, many cohorts showed improvement in facial symmetry, facial function, and quality of life. There remains a great gap in knowledge in this subject matter and a need for large well-designed prospective studies comparing this technique to other management options.

Systematic Review of Affective Computing Techniques for Infant Robot Interaction

Research studies on social robotics and human-robot interaction have gained insights into factors that influence people’s perceptions and behaviors towards robots. However, adults’ perceptions of robots may differ significantly from those of infants. Consequently, extending this knowledge also to infants’ attitudes toward robots is a growing field of research. Indeed, infant-robot interaction (IRI) is emerging as a critical and necessary area of research as robots are increasingly used in social environments, such as caring for infants with all types of disabilities, companionship, and education. Although studies have been conducted on the ability of robots to positively engage infants, little is known about the infants’ affective state when interacting with a robot. In this systematic review, technologies for infant affective state recognition relevant to IRI applications are presented and surveyed. Indeed, adapting techniques currently employed for infant’s emotion recognition to the field of IRI results to be a complex task, since it requires timely response while not interfering with the infant’s behavior. Those aspects have a crucial impact on the selection of the emotion recognition techniques and the related metrics to be used for this purpose. Therefore, this review is intended to shed light on the advantages and the current research challenges of the infants’ affective state recognition approaches in the IRI field, elucidates a roadmap for their use in forthcoming studies as well as potentially provide support to future developments of emotion-aware robots.

Microvascular Gracilis Free Flap: Single and Double Innervation

Facial paralysis (FP) is a devastating condition that can lead to significant aesthetic, social, and emotional morbidities for patients. For some patients with FP, free gracilis muscle transfer (FGMT) is the best option for smile restoration. Masseteric-driven FGMT produces a reliable voluntary smile. Cross-face nerve graft-driven FGMT can produce a spontaneous smile, but this technique has higher failure rates. Early studies suggest dual-innervation FGMT can produce a spontaneous smile while maintaining the reliability of masseteric-driven procedures. Great care should be taken during FGMT surgery to minimize facial bulk and place medial inset sutures that create a natural-appearing smile.

Morphological Features of Human Dendritic Spines

Dendritic spine features in human neurons follow the up-to-date knowledge presented in the previous chapters of this book. Human dendrites are notable for their heterogeneity in branching patterns and spatial distribution. These data relate to circuits and specialized functions. Spines enhance neuronal connectivity, modulate and integrate synaptic inputs, and provide additional plastic functions to microcircuits and large-scale networks. Spines present a continuum of shapes and sizes, whose number and distribution along the dendritic length are diverse in neurons and different areas. Indeed, human neurons vary from aspiny or "relatively aspiny" cells to neurons covered with a high density of intermingled pleomorphic spines on very long dendrites. In this chapter, we discuss the phylogenetic and ontogenetic development of human spines and describe the heterogeneous features of human spiny neurons along the spinal cord, brainstem, cerebellum, thalamus, basal ganglia, amygdala, hippocampal regions, and neocortical areas. Three-dimensional reconstructions of Golgi-impregnated dendritic spines and data from fluorescence microscopy are reviewed with ultrastructural findings to address the complex possibilities for synaptic processing and integration in humans. Pathological changes are also presented, for example, in Alzheimer's disease and schizophrenia. Basic morphological data can be linked to current techniques, and perspectives in this research field include the characterization of spines in human neurons with specific transcriptome features, molecular classification of cellular diversity, and electrophysiological identification of coexisting subpopulations of cells. These data would enlighten how cellular attributes determine neuron type-specific connectivity and brain wiring for our diverse aptitudes and behavior.

Sosyal Biliş Becerilerinin Sosyal Kaygı Üzerindeki Yordayıcı Etkisi

Bu çalışmanın temel amacı sosyal kaygı ile sosyal biliş becerileri (duygu tanıma/ayırt etme, zihin kuramı, atıf yanlılığı, sosyal işlevsellik) arasındaki ilişkiyi incelemek ve sosyal biliş becerilerinin sosyal kaygıyı yordama gücünü araştırmaktır. Çalışmada ayrıca sosyal kaygı, sosyal biliş becerileri ve depresyon puanlarının cinsiyet, yaş, bildirilen tanı durumu ve sosyal kaygı düzeyine göre farklılaşıp farklılaşmadığı araştırılmıştır. Çalışmanın örneklemini, 18-60 yaşları arasında bulunan toplam 385 kişi oluşturmuştur. Araştırma verileri çevrimiçi olarak Liebowitz Sosyal Anksiyete Ölçeği, Yüzde Dışavuran Duyguların Tanınması ve Ayırt Edilmesi Testi, Gözlerden Zihin Okuma Testi, İçsel, Kişisel ve Durumsal Atıflar Ölçeği, Sosyal İşlevsellik Ölçeği, Beck Depresyon Envanteri ve Sosyodemografik Bilgi Formu kullanılarak katılımcılardan toplanmıştır. Sosyal kaygı ile duygu tanıma, duygu ayırt etme ve gözlerden zihin okuma arasında negatif, dışsallaştırma yanlılığı ve depresyon ile ise pozitif yönde anlamlı ilişki olduğu belirlenmiştir. Depresyon, duygu tanıma ve ayırt etme, gözlerden zihin okuma ve öncül sosyal etkinlikler ölçek puanlarının sosyal kaygıyı anlamlı düzeyde yordadığı bulunmuştur. Bu değişkenler sosyal kaygıya ilişkin toplam varyansın %52’sini açıklamaktadır. Ayrıca, depresyon etkisi kontrol edildiğinde sosyal biliş becerilerinin sosyal kaygıya ilişkin varyansın %32’sini açıkladığı görülmüştür. Sosyal biliş becerilerindeki bozulmanın ve depresyon puanlarının sosyal kaygının artışıyla ilişkili olduğu belirlenmiştir. Araştırmadan elde edilen sonuçlara göre, sosyal kaygıyı önlemeye yönelik önerilerde bulunulmuştur. Müdahale programları içerisinde bireylerin kişilerarası iletişimi için önemli olan sosyal biliş becerilerini geliştirmeye yönelik etkinliklere yer verilmesinin yararlı olacağı önerilmektedir.

Clinical Assessments of Fracture Healing and Basic Science Correlates: Is There Room for Convergence?

PURPOSE OF REVIEW

The purpose of this review is to summarize the clinical and basic science methods used to assess fracture healing and propose a framework to improve the translational possibilities.

RECENT FINDINGS

Mainstays of fracture healing assessment include clinical examination, various imaging modalities, and assessment of function. Pre-clinical studies have yielded insight into biomechanical progression as well as the genetic, molecular, and cellular processes of fracture healing. Efforts are emerging to identify early markers to predict impaired healing and possibly early intervention to alter these processes. Despite of the differences in clinical and preclinical research, opportunities exist to unify and improve the translational efforts between these arenas to develop and optimize our ability to assess and predict fracture healing, thereby improving the clinical care of these patients.

Construction of face databases for tasks to recognize facial expressions of basic emotions: a systematic review

ABSTRACT. Recognizing the other's emotions is an important skill for the social context that can be modulated by variables such as gender, age, and race. A number of studies seek to elaborate specific face databases to assess the recognition of basic emotions in different contexts. Objectives: This systematic review sought to gather these studies, describing and comparing the methodologies used in their elaboration. Methods: The databases used to select the articles were the following: PubMed, Web of Science, PsycInfo, and Scopus. The following word crossing was used: “Facial expression database OR Stimulus set AND development OR Validation.” Results: A total of 36 articles showed that most of the studies used actors to express the emotions that were elicited from specific situations to generate the most spontaneous emotion possible. The databases were mainly composed of colorful and static stimuli. In addition, most of the studies sought to establish and describe patterns to record the stimuli, such as color of the garments used and background. The psychometric properties of the databases are also described. Conclusions: The data presented in this review point to the methodological heterogeneity among the studies. Nevertheless, we describe their patterns, contributing to the planning of new research studies that seek to create databases for new contexts.

Evaluation of film stimuli for the assessment of social-emotional processing: a pilot study

Background

Difficulties in top-down and bottom-up emotion generation have been proposed to play a key role in the progression of psychiatric disorders. The aim of the current study was to develop more ecologically valid measures of top-down interpretation biases and bottom-up evoked emotional responses.

Methods

A total of 124 healthy female participants aged 18-25 took part in the study. We evaluated two sets of 18 brief film clips. The first set of film clips presented ambiguous social situations designed to examine interpretation biases. Participants provided written interpretations of each ambiguous film clip which were subjected to sentiment analysis. We compared the films in terms of the valence of participants interpretations. The second set of film clips presented neutral and emotionally provoking social scenarios designed to elicit subjective and facial emotional responses. While viewing these film clips participants mood ratings and facial affect were recorded and analysed using exploratory factor analyses.

Results

Most of the 18 ambiguous film clips were interpreted in the expected manner while still retaining some ambiguity. However, participants were more attuned to the negative cues in the ambiguous film clips and three film clips were identified as unambiguous. These films clips were deemed unsuitable for assessing interpretation bias. The exploratory factor analyses of participants' mood ratings and evoked facial affect showed that the positive and negative emotionally provoking film clips formed their own factors as expected. However, there was substantial cross-loading of the neutral film clips when participants' facial expression data was analysed.

Discussion

A subset of the film clips from the two tasks could be used to assess top-down interpretation biases and bottom-up evoked emotional responses. Ambiguous negatively valenced film clips should have more subtle negative cues to avoid ceiling effects and to ensure there is enough room for interpretation.

Merging morphological and genetic evidence to assess hybridization in Western Eurasian late Pleistocene hominins

Previous scientific consensus saw human evolution as defined by adaptive differences (behavioural and/or biological) and the emergence of Homo sapiens as the ultimate replacement of non-modern groups by a modern, adaptively more competitive group. However, recent research has shown that the process underlying our origins was considerably more complex. While archaeological and fossil evidence suggests that behavioural complexity may not be confined to the modern human lineage, recent palaeogenomic work shows that gene flow between distinct lineages (for example, Neanderthals, Denisovans, early H. sapiens) occurred repeatedly in the late Pleistocene, probably contributing elements to our genetic make-up that might have been crucial to our success as a diverse, adaptable species. Following these advances, the prevailing human origins model has shifted from one of near-complete replacement to a more nuanced view of partial replacement with considerable reticulation. Here we provide a brief introduction to the current genetic evidence for hybridization among hominins, its prevalence in, and effects on, comparative mammal groups, and especially how it manifests in the skull. We then explore the degree to which cranial variation seen in the fossil record of late Pleistocene hominins from Western Eurasia corresponds with our current genetic and comparative data. We are especially interested in understanding the degree to which skeletal data can reflect admixture. Our findings indicate some correspondence between these different lines of evidence, flag individual fossils as possibly admixed, and suggest that different cranial regions may preserve hybridization signals differentially. We urge further studies of the phenotype to expand our ability to detect the ways in which migration, interaction and genetic exchange have shaped the human past, beyond what is currently visible with the lens of ancient DNA.

Are Face Masks a Problem for Emotion Recognition? Not When the Whole Body Is Visible

The rise of the novel COVID-19 virus has made face masks commonplace items around the globe. Recent research found that face masks significantly impair emotion recognition on isolated faces. However, faces are rarely seen in isolation and the body is also a key cue for emotional portrayal. Here, therefore, we investigated the impact of face masks on emotion recognition when surveying the full body. Stimuli expressing anger, happiness, sadness, and fear were selected from the BEAST stimuli set. Masks were added to these images and participants were asked to recognize the emotion and give a confidence level for that decision for both the masked and unmasked stimuli. We found that, contrary to some work viewing faces in isolation, emotion recognition was generally not impaired by face masks when the whole body is present. We did, however, find that when viewing masked faces, only the recognition of happiness significantly decreased when the whole body was present. In contrast to actual performance, confidence levels were found to decline during the Mask condition across all emotional conditions. This research suggests that the impact of masks on emotion recognition may not be as pronounced as previously thought, as long as the whole body is also visible.

More What Duchenne Smiles Do, Less What They Express

We comment on an article by Sheldon et al. from a previous issue of Perspectives (May 2021). They argued that the presence of positive emotion (Hypothesis 1), the intensity of positive emotion (Hypothesis 2), and chronic positive mood (Hypothesis 3) are reliably signaled by the Duchenne smile (DS). We reexamined the cited literature in support of each hypothesis and show that the study findings were mostly inconclusive, irrelevant, incomplete, and/or misread. In fact, there is no single (empirical) article that would unanimously support the idea that DSs function solely as indicators of felt positive affect. Additional evidence is reviewed, suggesting that DSs can be-and often are-displayed deliberately and in the absence of positive feelings. Although DSs may lead to favorable interpersonal perceptions and positive emotional responses in the observer, we propose a functional view that focuses on what facial actions-here specifically DSs-do rather than what they express.

Monitoring the emotional facial reactions of individuals with antisocial personality disorder during the retrieval of self-defining memories

While a deficit in the recognition of facial expression has been demonstrated in persons with antisocial personality disorder (ASPD), few studies have investigated how individuals with ASPD produce their own emotional facial expressions. This study examines the production of facial emotional expressions of male inpatients with ASPD in a forensic hospital compared with a control group as they retrieve autobiographical memories. This design constitutes a specific ecological experimental approach fostering the evocation of personal feelings. Two indicators characterizing the activation of facial expression were used: activation of emotional action units and emotional dominance. The results showed that individuals with ASPD 1) activated angrier facial expressions than control participants for both indicators, 2) displayed a higher dominance of angry facial expressions during the retrieval of positive self-defining memories than control participants and 3) recalled significant memories that were less associated with neutral facial states than the control sample, regardless of the valence of their memories. These findings highlight the core role of anger in ASPD and the possible development of pathological anger, which would distinguish trajectories toward anxious or mood disorders and trajectories characterized by external disorders.

Newly identified axon types of the facial nerve unveil supplemental neural pathways in the innervation of the face

INTRODUCTION

Neuromuscular control of the facial expressions is provided exclusively via the facial nerve. Facial muscles are amongst the most finely tuned effectors in the human motor system, which coordinate facial expressions. In lower vertebrates, the extracranial facial nerve is a mixed nerve, while in mammals it is believed to be a pure motor nerve. However, this established notion does not agree with several clinical signs in health and disease.

OBJECTIVES

To elucidate the facial nerve contribution to the facial muscles by investigating axonal composition of the human facial nerve. To reveal new innervation pathways of other axon types of the motor facial nerve.

METHODS

Different axon types were distinguished using specific molecular markers (NF, ChAT, CGRP and TH). To elucidate the functional role of axon types of the facial nerve, we used selective elimination of other neuronal support from the trigeminal nerve. We used retrograde neuronal tracing, three-dimensional imaging of the facial muscles, and high-fidelity neurophysiological tests in animal model.

RESULTS

The human facial nerve revealed a mixed population of only 85% motor axons. Rodent samples revealed a fiber composition of motor, afferents and, surprisingly, sympathetic axons. We confirmed the axon types by tracing the originating neurons in the CNS. The sympathetic fibers of the facial nerve terminated in facial muscles suggesting autonomic innervation. The afferent fibers originated in the facial skin, confirming the afferent signal conduction via the facial nerve.

CONCLUSION

These findings reveal new innervation pathways via the facial nerve, support the sympathetic etiology of hemifacial spasm and elucidate clinical phenomena in facial nerve regeneration.

Facial hair may slow detection of happy facial expressions in the face in the crowd paradigm

Human visual systems have evolved to extract ecologically relevant information from complex scenery. In some cases, the face in the crowd visual search task demonstrates an anger superiority effect, where anger is allocated preferential attention. Across three studies (N = 419), we tested whether facial hair guides attention in visual search and influences the speed of detecting angry and happy facial expressions in large arrays of faces. In Study 1, participants were faster to search through clean-shaven crowds and detect bearded targets than to search through bearded crowds and detect clean-shaven targets. In Study 2, targets were angry and happy faces presented in neutral backgrounds. Facial hair of the target faces was also manipulated. An anger superiority effect emerged that was augmented by the presence of facial hair, which was due to the slower detection of happiness on bearded faces. In Study 3, targets were happy and angry faces presented in either bearded or clean-shaven backgrounds. Facial hair of the background faces was also systematically manipulated. A significant anger superiority effect was revealed, although this was not moderated by the target's facial hair. Rather, the anger superiority effect was larger in clean-shaven than bearded face backgrounds. Together, results suggest that facial hair does influence detection of emotional expressions in visual search, however, rather than facilitating an anger superiority effect as a potential threat detection system, facial hair may reduce detection of happy faces within the face in the crowd paradigm.

The origin of smiling, laughing, and crying: The defensive mimic theory

Why do we leak lubricant from the eyes to solicit comfort from others? Why do we bare our teeth and crinkle our faces to express non-aggression? The defensive mimic theory proposes that a broad range of human emotional expressions evolved originally as exaggerated, temporally extended mimics of the fast, defensive reflexes that normally protect the body surface. Defensive reflexes are so important to survival that they cannot be safely suppressed; yet they also broadcast information about an animal's internal state, information that can potentially be exploited by other animals. Once others can observe and exploit an animal's defensive reflexes, it may be advantageous to the animal to run interference by creating mimic defensive actions, thereby manipulating the behaviour of others. Through this interaction over millions of years, many human emotional expressions may have evolved. Here, human social signals including smiling, laughing and crying, are compared component-by-component with the known, well-studied features of primate defensive reflexes. It is suggested that the defensive mimic theory can adequately account for the physical form of not all, but a large range of, human emotional expression.

Anatomical connections among the depressor supercilii, levator labii superioris alaeque nasi, and inferior fibers of orbicularis oculi: Implications for variation in human facial expressions

The aim of this study was to determine how the depressor supercilii (DS) connects to the levator labii superioris alaeque nasi (LLSAN) and inferior fibers of the orbicularis oculi (OOc INF) in the human midface. While grimacing, contraction of the DS with fibers connecting to the LLSAN and OOc INF can assist in pulling the medial eyebrow downward more than when these connecting fibers are not present. Contraction of these distinct connecting fibers between the DS and the LLSAN can also slightly elevate the nasal ala and upper lip. The DS was examined in 44 specimens of embalmed adult Korean cadavers. We found that the DS connected to the LLSAN or the OOc INF by muscle fibers or thin aponeuroses in 33 (75.0%) of the 44 specimens. The DS was connected to both the LLSAN and OOc INF by muscle fibers or aponeuroses and had no connection to either in 5 (11.4%) and 11 (25.0%) specimens, respectively. The DS was connected to the LLSAN by the muscle fibers and thin aponeuroses in 6 (13.6%) and 4 (9.1%) specimens, respectively. The DS was connected to the OOc INF by the muscle fibers and thin aponeuroses in 5 (11.4%) and 23 (52.3%) specimens, respectively. Our findings regarding the anatomical connections of the glabellar region DS to the midface LLSAN and OOc INF provide insights on the dynamic balance between the brow depressors such as the DS and brow-elevating muscle and contribute to understanding the anatomical origins of individual variation in facial expressions. These results can also improve the safety, predictability, and aesthetics of treatments for the glabellar region with botulinum toxin type A and can be helpful when performing electromyography.

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).

Human face and gaze perception is highly context specific and involves bottom-up and top-down neural processing

This review summarizes human perception and processing of face and gaze signals. Face and gaze signals are important means of non-verbal social communication. The review highlights that: (1) some evidence is available suggesting that the perception and processing of facial information starts in the prenatal period; (2) the perception and processing of face identity, expression and gaze direction is highly context specific, the effect of race and culture being a case in point. Culture affects by means of experiential shaping and social categorization the way in which information on face and gaze is collected and perceived; (3) face and gaze processing occurs in the so-called 'social brain'. Accumulating evidence suggests that the processing of facial identity, facial emotional expression and gaze involves two parallel and interacting pathways: a fast and crude subcortical route and a slower cortical pathway. The flow of information is bi-directional and includes bottom-up and top-down processing. The cortical networks particularly include the fusiform gyrus, superior temporal sulcus (STS), intraparietal sulcus, temporoparietal junction and medial prefrontal cortex.

Infants are sensitive to cultural differences in emotions at 11 months

A myriad of emotion perception studies has shown infants' ability to discriminate different emotional categories, yet there has been little investigation of infants' perception of cultural differences in emotions. Hence little is known about the extent to which culture-specific emotion information is recognised in the beginning of life. Caucasian Australian infants of 10-12 months participated in a visual-paired comparison task where their preferential looking patterns to three types of infant-directed emotions (anger, happiness, surprise) from two different cultures (Australian, Japanese) were examined. Differences in racial appearances were controlled. Infants exhibited preferential looking to Japanese over Caucasian Australian mothers' angry and surprised expressions, whereas no difference was observed in trials involving East-Asian Australian mothers. In addition, infants preferred Caucasian Australian mothers' happy expressions. These findings suggest that 11-month-olds are sensitive to cultural differences in spontaneous infant-directed emotional expressions when they are combined with a difference in racial appearance.

Neurotization Preferences in Smile Reanimation: A Discrete Choice Experiment

BACKGROUND

Common donor nerve options in smile reanimation include ipsilateral trigeminal motor or contralateral facial nerve branches. Neurotization preference may be influenced by multiple factors, whose relative importance remains poorly understood. In this article, decision-making in smile reanimation is assessed using a stated preference model.

METHODS

Qualitative interviews with facial palsy patients identified five relevant attributes for study: smile type ("smile when biting" versus "smile spontaneously" as proxies for trigeminal versus cross-facial neurotization), number of operations, success rates, complication rates, and side effects. Community volunteers (n = 250) completed a discrete-choice experiment relevant to free muscle transfer for smile reanimation. Preoperative and postoperative states were demonstrated through video vignettes, together with explanation of surgical risks, consequences, and benefits. Attribute importance was modeled using hierarchical Bayes estimation.

RESULTS

Two hundred forty-one responses met quality controls. Attribute importance ranked as follows: chance of success, 37.3 percent; smile type, 21.4 percent; side effects, 13.9 percent; complication rates, 13.8; and number of operations, 13.6 percent. All attributes significantly correlated with decision making (p < 0.0001). An aggregate response model revealed most participants (67.6 percent; standard error, 3.0 percent) preferred smile reanimation by cross-facial (assuming a success rate of 80 percent) as opposed to ipsilateral trigeminal motor branch neurotization. When the success rate for cross-facial neurotization was reduced below 67 percent, trigeminal neurotization was preferred.

CONCLUSIONS

Despite a higher risk of failure, most respondents preferred a cross-facial as opposed to trigeminal neurotization strategy for smile reanimation. These findings highlight the complexity of decision-making and need for individualized risk tolerance assessment in the field of facial reanimation.

Lessons from Gracilis Free Tissue Transfer for Facial Paralysis: Now versus 10 Years Ago

Outcomes following free gracilis muscle transfer have steadily improved during the past decade. Areas for continued improvement include re-creating natural smile vectors, improving midface symmetry, minimizing scarring, improving spontaneity, and increasing reliability using various neural sources. Outcome standardization, pooled data collection, and remote data acquisition methods will facilitate comparative effectiveness research and continued surgical advancements.

Shape-invariant encoding of dynamic primate facial expressions in human perception

Dynamic facial expressions are crucial for communication in primates. Due to the difficulty to control shape and dynamics of facial expressions across species, it is unknown how species-specific facial expressions are perceptually encoded and interact with the representation of facial shape. While popular neural network models predict a joint encoding of facial shape and dynamics, the neuromuscular control of faces evolved more slowly than facial shape, suggesting a separate encoding. To investigate these alternative hypotheses, we developed photo-realistic human and monkey heads that were animated with motion capture data from monkeys and humans. Exact control of expression dynamics was accomplished by a Bayesian machine-learning technique. Consistent with our hypothesis, we found that human observers learned cross-species expressions very quickly, where face dynamics was represented largely independently of facial shape. This result supports the co-evolution of the visual processing and motor control of facial expressions, while it challenges appearance-based neural network theories of dynamic expression recognition.

Social Information Processing in Substance Use Disorders: Insights From an Emotional Go-Nogo Task

Positive social connections are crucial for recovery from Substance Use Disorder (SUD). Of interest is understanding potential social information processing (SIP) mediators of this effect. To explore whether persons with different SUD show idiosyncratic biases toward social signals, we administered an emotional go-nogo task (EGNG) to 31 individuals with Cocaine Use Disorder (CoUD), 31 with Cannabis Use Disorder (CaUD), 79 with Opioid Use Disorder (OUD), and 58 controls. Participants were instructed to respond to emotional faces (Fear/Happy) but withhold responses to expressionless faces in two task blocks, with the reverse instruction in the other two blocks. Emotional faces as non-targets elicited more "false alarm" (FA) commission errors as a main effect. Groups did not differ in overall rates of hits (correct responses to target faces), but participants with CaUD and CoUD showed reduced rates of hits (relative to controls) when expressionless faces were targets. OUD participants had worse hit rates [and slower reaction times (RT)] when fearful faces (but not happy faces) were targets. CaUD participants were most affected by instruction effects (respond/"go" vs withhold response/"no-go" to emotional face) on discriminability statistic A. Participants were faster to respond to happy face targets than to expressionless faces. However, this pattern was reversed in fearful face blocks in OUD and CoUD participants. This experiment replicated previous findings of the greater salience of expressive face images, and extends this finding to SUD, where persons with CaUD may show even greater bias toward emotional faces. Conversely, OUD participants showed idiosyncratic behavior in response to fearful faces suggestive of increased attentional disruption by fear. These data suggest a mechanism by which positive social signals may contribute to recovery.

Grumpy face during adult sleep: A clue to negative emotion during sleep?

Negative facial expressions and frowns have been studied (albeit more rarely than smiles) in fetus' and neonate' sleep, but they have not been investigated during adult sleep. Video polysomnography (including corrugator muscle electromyography and face-focussed video) was used to study negative facial expressions in sleeping adults, including healthy subjects and patients with/out parasomnia. Frowns were observed during sleep in 89/91 (97.8%) adults during normal (29 healthy subjects) and abnormal sleep (29 patients without parasomnia, 15 patients with disorders of arousal and 18 patients with rapid eye movement [REM] sleep behaviour disorder [RBD]). In healthy subjects, the following events occurred in decreasing frequency: isometric corrugator activations, brief frowns, and then prolonged frowns and raised eyebrows (both similarly rare). Frowns predominated in REM sleep, and had a lower frequency in non-REM sleep. In healthy subjects, frowns were elementary and not associated with other face movements to the point of composing negative expressions. In contrast, frowns were occasionally associated with overt negative facial expressions in REM sleep in patients with RBD and a young patient with night terrors. They included mostly painful expressions and rarely sadness and anger in connection with apparently negative behaviours (shouts, painful moaning, and speeches). Frowns persist during normal sleep (mostly in REM sleep) in adults, but overt negative facial expressions are restricted to patients with parasomnia. Whether elementary frowns translate a negative dream emotion should be determined, but overt negative facial expressions during RBD could be used as a direct access to dream emotions.

Non-verbal Adaptation to the Interlocutors' Inner Characteristics: Relevance, Challenges, and Future Directions

Human diversity cannot be denied. In our everyday social interactions, we constantly experience the fact that each individual is a unique combination of characteristics with specific cultural norms, roles, personality, and mood. Efficient social interaction thus requires an adaptation of communication behaviors to each specific interlocutor that one encounters. This is especially true for non-verbal communication that is more unconscious and automatic than verbal communication. Consequently, non-verbal communication needs to be understood as a dynamic and adaptive process in the theoretical modeling and study of social interactions. This perspective paper presents relevance, challenges, and future directions for the study of non-verbal adaptation in social interactions. It proposes that non-verbal adaptability is more pertinently studied as adaptation to interlocutor's inner characteristics (i.e., expectations or preferences) than to interlocutor's behaviors per se, because behaviors are communication messages that individuals interpret in order to understand their interlocutors. The affiliation and control dimensions of the Interpersonal Circumplex Model are proposed as a framework to measure both the interlocutors' inner characteristics (self-reported) and the individuals' non-verbal responses (external coders). These measures can then be compared across different interactions to assess an actual change in behavior tailored to different interlocutors. These recommendations are proposed in the hope of generating more research on the topic of non-verbal adaptability. Indeed, after having gathered the evidence on average effects of non-verbal behaviors, the field can go further than a “one size fits all” approach, by investigating the predictors, moderators, and outcomes of non-verbal adaptation to the interlocutors' inner characteristics.

Selective Denervation of the Facial Dermato-Muscular Complex in the Rat: Experimental Model and Anatomical Basis

The facial dermato-muscular system consists of highly specialized muscles tightly adhering to the overlaying skin and thus form a complex morphological conglomerate. This is the anatomical and functional basis for versatile facial expressions, which are essential for human social interaction. The neural innervation of the facial skin and muscles occurs via branches of the trigeminal and facial nerves. These are also the most commonly pathologically affected cranial nerves, often requiring surgical treatment. Hence, experimental models for researching these nerves and their pathologies are highly relevant to study pathophysiology and nerve regeneration. Experimental models for the distinctive investigation of the complex afferent and efferent interplay within facial structures are scarce. In this study, we established a robust surgical model for distinctive exploration of facial structures after complete elimination of afferent or efferent innervation in the rat. Animals were allocated into two groups according to the surgical procedure. In the first group, the facial nerve and in the second all distal cutaneous branches of the trigeminal nerve were transected unilaterally. All animals survived and no higher burden was caused by the procedures. Whisker pad movements were documented with video recordings 4 weeks after surgery and showed successful denervation. Whole-mount immunofluorescent staining of facial muscles was performed to visualize the innervation pattern of the neuromuscular junctions. Comprehensive quantitative analysis revealed large differences in afferent axon counts in the cutaneous branches of the trigeminal nerve. Axon number was the highest in the infraorbital nerve (28,625 ± 2,519), followed by the supraorbital nerve (2,131 ± 413), the mental nerve (3,062 ± 341), and the cutaneous branch of the mylohyoid nerve (343 ± 78). Overall, this surgical model is robust and reliable for distinctive surgical deafferentation or deefferentation of the face. It may be used for investigating cortical plasticity, the neurobiological mechanisms behind various clinically relevant conditions like facial paralysis or trigeminal neuralgia as well as local anesthesia in the face and oral cavity.

Reversing the Luminance Polarity of Control Faces: Why Are Some Negative Faces Harder to Recognize, but Easier to See?

Control stimuli are key for understanding the extent to which face processing relies on holistic processing, and affective evaluation versus the encoding of low-level image properties. Luminance polarity (LP) reversal combined with face inversion is a popular tool for severely disrupting the recognition of face controls. However, recent findings demonstrate visibility-recognition trade-offs for LP-reversed faces, where these face controls sometimes appear more salient despite being harder to recognize. The present report brings together findings from image analysis, simple stimuli, and behavioral data for facial recognition and visibility, in an attempt to disentangle instances where LP-reversed control faces are associated with a performance bias in terms of their perceived salience. These findings have important implications for studies of subjective face appearance, and highlight that future research must be aware of behavioral artifacts due to the possibility of trade-off effects.

Dynamics of facial actions for assessing smile genuineness

Applying computer vision techniques to distinguish between spontaneous and posed smiles is an active research topic of affective computing. Although there have been many works published addressing this problem and a couple of excellent benchmark databases created, the existing state-of-the-art approaches do not exploit the action units defined within the Facial Action Coding System that has become a standard in facial expression analysis. In this work, we explore the possibilities of extracting discriminative features directly from the dynamics of facial action units to differentiate between genuine and posed smiles. We report the results of our experimental study which shows that the proposed features offer competitive performance to those based on facial landmark analysis and on textural descriptors extracted from spatial-temporal blocks. We make these features publicly available for the UvA-NEMO and BBC databases, which will allow other researchers to further improve the classification scores, while preserving the interpretation capabilities attributed to the use of facial action units. Moreover, we have developed a new technique for identifying the smile phases, which is robust against the noise and allows for continuous analysis of facial videos.

Semantic Space Theory: A Computational Approach to Emotion

Within affective science, the central line of inquiry, animated by basic emotion theory and constructivist accounts, has been the search for one-to-one mappings between six emotions and their subjective experiences, prototypical expressions, and underlying brain states. We offer an alternative perspective: semantic space theory. This computational approach uses wide-ranging naturalistic stimuli and open-ended statistical techniques to capture systematic variation in emotion-related behaviors. Upwards of 25 distinct varieties of emotional experience have distinct profiles of associated antecedents and expressions. These emotions are high-dimensional, categorical, and often blended. This approach also reveals that specific emotions, more than valence, organize emotional experience, expression, and neural processing. Overall, moving beyond traditional models to study broader semantic spaces of emotion can enrich our understanding of human experience.

Reliability Between In-Person and Still Photograph Assessment of Facial Function in Facial Paralysis Using the eFACE Facial Grading System

Importance: Assessing facial function using high-quality photographs would improve long-term and objective outcomes tracking in facial palsy, facilitate automated facial grading using artificial intelligence algorithms, and allow for remote follow up. Objective: To determine agreement between in-person and photographic electronic facial function scale (eFACE) assessments, and evaluate inter-rater reliability of photographic eFACE evaluation. Design, Setting, and Participants: Retrospective review of eFACE scores from in-person interviews and standardized photographs using the Massachusetts Eye and Ear (MEE) Standard Facial Palsy Dataset. Main Outcomes and Measures: eFACE total scores and subset scores determined by two experienced facial reanimation surgeons in person and from photographs. Results: Intraclass correlation coefficients for eFACE scores were 0.96 (95% CI 0.94 to 0.97) for total scores, 0.99 (95% CI 0.989 to 0.995) for static scores, 0.82 (95% CI 0.74 to 0.88) for dynamic scores, and 0.98 (95% CI 0.97 to 0.99) for synkinesis scores. Photographic and in-person scores had a mean difference of -0.64 (95% CI -2.05 to 0.77; p = 0.37) for total score, -1.58 (95% CI -4.22 to 1.05; p = 0.24) for the static subset, 0.14 (95% CI -1.70 to 1.97; p = 0.88) for the dynamic subset, and -1.11 (95% CI -3.09 to 0.86; p = 0.26) for the synkinetic subset. Bland-Altman analysis showed no trend for increasing differences in total score or subset scores. Conclusions: eFACE assessment obtained via photographs exhibits excellent inter-rater reliability and strong agreement with in-person assessment, demonstrating facial symmetry in facial palsy patients can be monitored using standardized frontal photographs.

Experience has a limited effect on humans' ability to predict the outcome of social interactions in children, dogs and macaques

The ability to predict others' behaviour represents a crucial mechanism which allows individuals to react faster and more appropriately. To date, several studies have investigated humans' ability to predict conspecifics' behaviour, but little is known on our ability to predict behaviour in other species. Here, we aimed to test humans' ability to predict social behaviour in dogs, macaques and humans, and assess the role played by experience and evolution on the emergence of this ability. For this purpose, we presented participants with short videoclips of real-life social interactions in dog, child and macaque dyads, and then asked them to predict the outcome of the observed interactions (i.e. aggressive, neutral or playful). Participants were selected according to their previous species-specific experience with dogs, children and non-human primates. Our results showed a limited effect of experience on the ability to predict the outcome of social interactions, which was mainly restricted to macaques. Moreover, we found no support to the co-domestication hypothesis, in that participants were not especially skilled at predicting dog behaviour. Finally, aggressive outcomes in dogs were predicted significantly worse than playful or neutral ones. Based on our findings, we suggest possible lines for future research, like the inclusion of other primate species and the assessment of cultural factors on the ability to predict behaviour across species.