The proposal that there are specific adaptations for the expression and detection of pain appears premature on both conceptual and empirical grounds. We discuss criteria for the validation of a pain facial expression. We also describe recent findings from our lab on coping styles and pain expression, which illustrate the importance of considering individual differences when proposing evolutionary explanations.

A functional interpretation of facial expressions of pain is welcome. Facial expressions of pain may be useful not only for communication, such as inviting help. They may also be of direct use, as parts of writhing pain behavior patterns, serving to get rid of pain stimuli and/or to suppress pain sensations by something akin to hyperstimulation analgesia.

This paper proposes that human expression of pain in the presence or absence of caregivers, and the detection of pain by observers, arises from evolved propensities. The function of pain is to demand attention and prioritise escape, recovery, and healing; where others can help achieve these goals, effective communication of pain is required. Evidence is reviewed of a distinct and specific facial expression of pain from infancy to old age, consistent across stimuli, (...) and recognizable as pain by observers. Voluntary control over amplitude is incomplete, and observers can better detect pain that the individual attempts to suppress rather than amplify or simulate. In many clinical and experimental settings, the facial expression of pain is incorporated with verbal and nonverbal vocal activity, posture, and movement in an overall category of pain behaviour. This is assumed by clinicians to be under operant control of social contingencies such as sympathy, caregiving, and practical help; thus, strong facial expression is presumed to constitute an attempt to manipulate these contingencies by amplification of the normal expression. Operant formulations support skepticism about the presence or extent of pain, judgments of malingering, and sometimes the withholding of caregiving and help. To the extent that pain expression is influenced by environmental contingencies, however, could equally plausibly constitute the release of suppression according to evolved contingent propensities that guide behaviour. Pain has been largely neglected in the evolutionary literature and the literature on expression of emotion, but an evolutionary account can generate improved assessment of pain and reactions to it. (shrink)

Facial expressions of pain may be best conceptualized as an example of an evolved propensity to communicate distress, rather than as a distinct category of facial expression. The operant model goes beyond the evolutionary account, as it can explain how the (facial) expression of pain can become maladaptive as a result of its capability to elicit attention and caring behavior in the observer.

This paper proposes that human expression of pain in the presence or absence of caregivers, and the detection of pain by observers, arises from evolved propensities. The function of pain is to demand attention and prioritise escape, recovery, and healing; where others can help achieve these goals, effective communication of pain is required. Evidence is reviewed of a distinct and specific facial expression of pain from infancy to old age, consistent across stimuli, (...) and recognizable as pain by observers. Voluntary control over amplitude is incomplete, and observers can better detect pain that the individual attempts to suppress rather than amplify or simulate. In many clinical and experimental settings, the facial expression of pain is incorporated with verbal and nonverbal vocal activity, posture, and movement in an overall category of pain behaviour. This is assumed by clinicians to be under operant control of social contingencies such as sympathy, caregiving, and practical help; thus, strong facial expression is presumed to constitute an attempt to manipulate these contingencies by amplification of the normal expression. Operant formulations support skepticism about the presence or extent of pain, judgments of malingering, and sometimes the withholding of caregiving and help. To the extent that pain expression is influenced by environmental contingencies, however, “amplification” could equally plausibly constitute the release of suppression according to evolved contingent propensities that guide behaviour. Pain has been largely neglected in the evolutionary literature and the literature on expression of emotion, but an evolutionary account can generate improved assessment of pain and reactions to it. Key Words: adaptation; evolutionary psychology; facial expression; pain. (shrink)

The experience of pain appears to be associated, from early infancy and across pain stimuli, with a consistent facial expression in humans. A social function is proposed for this: the communication of pain and the need for help to observers, to whom information about danger is of value, and who may provide help within a kin or cooperative relationship. Some commentators have asserted that the evidence is insufficient to account for the consistency of the face, (...) as judged by technical means or in the perceptions of observers, or that facial expression is epiphenomenal to a gross behavioural defensive response to pain. The major criticism is that it is unnecessary to invoke evolutionary mechanisms beyond the emergence of an unconditioned facial response to pain in neonates, subsequently shaped and maintained by instrumental and social reinforcement throughout life. These criticisms are addressed, acknowledging the need for further data to address some, and elaborating the areas in which evolutionary and operant mechanisms would predict different behavioural interactions, rather than acting synergistically. Several supportive commentaries propose extending evolutionarily-based hypotheses to sex differences, the complexities of others' responses within the social relationship, and the role of empathy. A number of commentators provided valuable suggestions for experimental paradigms or methodological issues. Overall, addressing these issues indicates the need for further conceptual development and for collection of data specifically in relation to these hypotheses. (shrink)

The experience of pain appears to be associated, from early infancy and across pain stimuli, with a consistent facial expression in humans. A social function is proposed for this: the communication of pain and the need for help to observers, to whom information about danger is of value, and who may provide help within a kin or cooperative relationship. Some commentators have asserted that the evidence is insufficient to account for the consistency of the face, (...) as judged by technical means or in the perceptions of observers, or that facial expression is epiphenomenal to a gross behavioural defensive response to pain. The major criticism is that it is unnecessary to invoke evolutionary mechanisms beyond the emergence of an unconditioned facial response to pain in neonates, subsequently shaped and maintained by instrumental and social reinforcement throughout life. These criticisms are addressed, acknowledging the need for further data to address some, and elaborating the areas in which evolutionary and operant mechanisms would predict different behavioural interactions, rather than acting synergistically. Several supportive commentaries propose extending evolutionarily-based hypotheses to sex differences, the complexities of others' responses within the social relationship, and the role of empathy. A number of commentators provided valuable suggestions for experimental paradigms or methodological issues. Overall, addressing these issues indicates the need for further conceptual development and for collection of data specifically in relation to these hypotheses. (shrink)

Facial responses to pain might be the result of evolution but Williams' interesting “Just So” story provides no convincing evidence for her hypothesis. Contrary to her hope, casting facial action in an evolutionary perspective will probably not reduce the common practice of health care professionals blaming patients for their problems; instead, it may discourage appropriate treatment.

An automated system for monitoring facial expressions could increase the reliability, sensitivity, and precision of the research on the relationship between facial signs and experiences of pain, and it could lead to new insights and diagnostic methods. This commentary examines whether the research on facial expression of pain, as reported by Williams, provides a sufficient basis for machine understanding of pain-associated facial expressions.

In children experiencing pain, the study of the social context of facial expressions might help to evaluate evolutionary and conditioning hypotheses of behavioural development. Social motivations and influences may be complex, as seen in studies of children having their ears pierced, and in studies of everyday pain in children. A study of opposing predictions of the long-term effects of parental caregiving is suggested.

As a product of natural selection, pain behavior must serve an adaptive function for the species beyond the accurate portrayal of the pain experience. Pain behavior does not simply refer to the pain experience, but promotes survival of the species in various and complex ways. This means that there is no purely respondent or operant pain behavior found in nature.

The facial expression of pain is the end product of a complex process that is, in part, emotional. The evolutionary study of facial expression must account for the social nature of human consciousness and should address the questions of why empathy exists, the adaptive importance of empathy, and whether facial expression is a mechanism of empathy and second-person consciousness.

Williams and the many studies she considers appear to assume that voluntary amplification in facial expression of pain implies dissimulation. In fact, the behavioral ecology model of pain expression is consistent with amplification when subjects in pain are in the presence of others disposed to render aid, and that amplification may well be voluntary.

Women typically report more pain than men, as well as exhibit specific sex differences in the perception and emotional expression of pain. We present evidence that sex is a significant variable in the evolution of facial expression of pain.

I agree with Williams that evolutionary theory provides the best account of the pain expression. We may disagree as to whether pain has an emotional dimension or includes discrete basic emotions as integral components. I interpret basic emotion expressions that occur contemporaneously with pain expression as representing separate but highly interactive systems, each with distinct adaptive functions.

The ArgumentPain has important biomedical socioanthropological, semiotic, and other facets. In this contribution pain and the experssion of pain are looked at from the perspective of evolutionary biology, utilizing, among others, cross-cultural data from field work in Melanesia.No other being cares for sick and suffering conspecifics in the way humans do. Notwithstanding aggression and neglect, common in all cultures, human societies can be characterized as empathic, comforting, and promoting the health and well-being of their members. One important stimulus (...) triggering this caring response in others is the expression of pain. The nonverbal channel of communication, particularly certain universal — i.e., culture-independent facial expressions, gestures, and body postures, convey much of the message from the painstricken person to the group.These behaviors signal the person's physical and psychical pain, sadness, grief, and despair in ways very similar to the signs given by infants and small children: the body loses tonus and sinks or drops to the ground, the gestures are those of helplessness. Pain and grief may be so strong that control is lost not only over the body's posture but also over the mind's awareness. In such cases the afflicted person may carry out actions endangering himself or others. In general, these behavior patterns resemble those of infants in situations of distress and danger, and it is not surprising that the response of the members of the group is basically parental: taking care, assisting and consoling.Perceptive and behavioral patterns which developed in the course of avian and mammalian phylogeny to serve the well-being of the young have proven, as was shown by Eibl-Eibesfeldt, to be powerful building blocks for actions in other spheres of human interaction. Love is one such field, the reactions to a conspecific suffering pain is another. (shrink)

What differentiates expressions of pain from other facial expressions? Which facial features convey the most information in an expression of pain? To answer such questions we can explore the expertise of human observers using psychophysical experiments. Techniques such as change detection and visual search can advance our understanding of facial expressions of pain and of evolved mechanisms for detecting these expressions.

Evolutionary explanations of pain expression require modeling social adaptations in a context where the role of health professionals as potential caregivers, conflicts with their status as relative strangers. As signals of help elicitation or of alarm, facial pain displays and responses to displays, particularly in the upper face, are expected to conform to this evolutionarily novel clinical context.

Social exclusion is an emotionally painful experience that leads to various alterations in socio-emotional processing. The perceptual and emotional consequences that may arise from experiencing social exclusion can vary depending on the paradigm used to manipulate it. Exclusion paradigms can vary in terms of the severity and duration of the leading exclusion experience, thereby classifying it as either a short-term or long-term experience. The present study aimed to study the impact of exclusion on socio-emotional processing using different paradigms that caused (...) experiencing short-term and imagining long-term exclusion. Ambiguous facial emotions were used as socio-emotional cues. In study 1, the Ostracism Online paradigm was used to manipulate short-term exclusion. In study 2, a new sample of participants imagined long-term exclusion through the future life alone paradigm. Participants of both studies then completed a facial emotion recognition task consisting of morphed ambiguous facial emotions. By means of Point of Subjective Equivalence analyses, our results indicate that the experience of short-term exclusion hinders recognising happy facial expressions. In contrast, imagining long-term exclusion causes difficulties in recognising sad facial expressions. These findings extend the current literature, suggesting that not all social exclusion paradigms affect socio-emotional processing similarly. (shrink)

Abusive supervision negatively affects its direct victims. However, recent studies have begun to explore how abusive supervision affects third parties. We use the emotion-based process model of schadenfreude as a basis to suggest that third parties will experience schadenfreude and increase their work engagement as a response to peer abusive supervision. Furthermore, we suggest that the context of competitive goal interdependence facilitates the indirect relationship between PAS and third parties’ work engagement on schadenfreude. We use a mixed-method approach to test (...) our hypotheses. Data from an experimental study conducted by facial expression analysis technology and a multi‐wave field study generally support our hypotheses. Overall, our study extends PAS literature and meaningfully informs practitioners who aim to promote ethical workplace environments. (shrink)

Williams argues that humans have evolved special purpose adaptations for eliciting medical attention from others, such as a specific facial expression of pain. She also recognises that such adaptations would almost certainly have coevolved with adaptations for providing and responding to medical care. The placebo response may be one such adaptation, and any evolutionary account of pain must also address this important phenomenon.

According to Williams, human facially expressed pain, and its perception by conspecifics, is generated by evolved mechanisms. We argue that a key variable – sex (male, female) – needs to be considered for a complete theory of pain expression and perception. To illustrate, we cite findings on sex differences in pain and pain perception, and in crying and crying responsiveness.

We argue that pain behaviour cannot be wholly accounted for within the operant model of Fordyce (1976). Many pain behaviours, including facial expression, are not socially reinforced but are evolutionarily predetermined. We urge researchers to take into consideration other learning accounts. Building on the idea that pain sufferers learn to suppress the expression of pain, we begin the development of a framework for a relational understanding of pain complaint.

Human pain experience and expression evolved to serve a range of social functions, including warning others, eliciting care, and influencing interpersonal relationships, as well as to protect from physical danger. Study of the relatively specific, involuntary, and salient facial display of pain permits examination of these roles, extending our appreciation of pain beyond the prevalent narrow focus on somatosensory mechanisms.

No adequate evidence exists for the evolution of facial pain expression and detection mechanisms, as opposed to social-learning processes. Although brain affective/emotional processes, and resulting whole body action patterns, have surely evolved, we should also aspire to monitor human suffering by direct neural measures rather than by more indirect indices.

Is it not surprising that we look with so much pleasure and emotion at works of art that were made thousands of years ago? Works depicting people we do not know, people whose backgrounds are usually a mystery to us, who lived in a very different society and time and who, moreover, have been ‘frozen’ by the artist in a very deliberate pose. It was the Classical Greek philosopher Aristotle who observed in his Poetics that people could apparently be moved (...) even by the imitation of a person or an act. And although we are usually well aware that it is a simulacrum, not a real situation, it nevertheless sometimes seems as if we ourselves are standing there on the stage or in the painting, so intense and emotional is our response, even though we are just spectators. Aristotle concludes from this that we have intellectual capacities which allow us put ourselves in another’s place and consequently to react to simulated situations as though they are actually happening to us, here and now. In this process, he contends, observation, memory, imagination and emotions are crucial elements. In the past it was not customary to invoke human mental faculties to explain our response to works of art. The Ancient Greeks, after all, knew little about the human body or brain and usually referred to the extended world of the gods in their endeavours to comprehend the ‘inner world’ of human beings. In our time the situation is completely different—such an allusion to the brain no longer surprises us. Whether it is about the mystery of the consciousness, the question of free will or accounts of bizarre psychological aberrations or disorders, we have become accustomed to references to parts of the brain, to images of brain scans, to reports about neural networks and the like. However, because there are so many factors that play a part in our appreciation of works of art we need a complex explanation for it, and it is not enough to look only at certain properties of the brain that are determined by evolution. Those properties are shared by every human being, and so are rather useless in explaining people’s different reactions to the same work of art. Evidently the brains of individuals differ so much that they make it possible for people to respond differently to one and the same artwork. This, of course, raises questions concerning the painted emotions that can be seen in this exhibition. Virtually everyone, after all, is fascinated by such paintings and usually recognizes the emotions they represent. The reactions to these painted emotions are also often similar. This is probably why artworks like this are generally highly valued, then and now, here and elsewhere: from the enigmatically smiling Egyptian Queen Nefertiti and the startled Rembrandt to a seemingly despairing African mask. Aristotle observed that in the theatre players imitate actions that are associated with emotions in a number of ways and that these emotions are shared in a particular fashion by the playwright, the actors and the audience. The audience may even be carried away by these emotions to such an extent that they are in a sense purged of them and can subsequently leave the theatre relieved. Are such emotional reactions perhaps related to the fact that emotions are universal and that brains respond similarly to them? Is this why we can so readily identify painted emotions? May we therefore also assume that the properties of the brain determined by evolution help us to explain these emotions? In answering these questions we shall discuss a number of insights into emotions in psychology and brain science and explore some theories about the possible function of emotions and their expression. (shrink)

There are many ways to assess face perception skills. In this study, we describe a novel task battery FEAST (Facial Expression Action Stimulus Test) developed to test recognition of identity and expressions of human faces as well as stimulus control categories. The FEAST consists of a neutral and emotional face memory task, a face and object identity matching task, a face and house part-to-whole matching task, and a human and animal facial expression matching task. The identity (...) and part-to-whole matching tasks contain both upright and inverted conditions. The results provide reference data of a healthy sample of controls in two age groups for future users of the FEAST. (shrink)

Facial expression recognition plays a significant part in artificial intelligence and computer vision. However, most of facial expression recognition methods have not obtained satisfactory results based on low-level features. The existed methods used in facial expression recognition encountered the major issues of linear inseparability, large computational burden, and data redundancy. To obtain satisfactory results, we propose an innovative deep learning model using the kernel entropy component analysis network and directed acyclic graph support vector machine. (...) We use the KECANet in the feature extraction stage. In the stage of output, binary hashing and blockwise histograms are adopted. We sent the final output features to the DAGSVM classifier for expression recognition. We test the performance of our proposed method on three databases of CK+, JAFFE, and CMU Multi-PIE. According to the experiment results, the proposed method can learn high-level features and provide more recognition information in the stage of training, obtaining a higher recognition rate. (shrink)

We discuss here one of our projects, aimed at developing an automatic facial expression interpreter, mainly in terms of signaled emotions. We present some of the relevant findings on facial expressions from cognitive science and psychology that can be understood by and be useful to researchers in Human-Computer Interaction and Artificial Intelligence. We then give an overview of HCI applications involving automated facial expression recognition, we survey some of the latest progresses in this area reached (...) by various approaches in computer vision, and we describe the design of our facial expression recognizer. We also give some background knowledge about our motivation for understanding facial expressions and we propose an architecture for a multimodal intelligent interface capable of recognizing and adapting to computer users' affective states. Finally, we discuss current interdisciplinary issues and research questions which will need to be addressed for further progress to be made in the promising area of computational facial expression recognition. (shrink)

Facial expression is a mode of close‐proximity non‐vocal communication used by primates and is produced by mimetic/facial musculature. Arguably, primates make the most‐intricate facial displays and have some of the most‐complex facial musculature of all mammals. Most of the earlier ideas of primate mimetic musculature, involving its function in facial displays and its evolution, were essentially linear “scala natural” models of increasing complexity. More‐recent work has challenged these ideas, suggesting that ecological factors and social (...) systems have played a much larger role in explaining the diversity of structures than previously believed. The present review synthesizes the evidence from gross muscular, microanatomical, behavioral and neurobiological studies in order to provide a preliminary analysis of the factors responsible for the evolution of primate facial musculature with comparisons to general mammals. In addition, the unique structure, function and evolution of human mimetic musculature are discussed, along with the potential influential roles of human speech and eye gaze. BioEssays 30:212–225, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

Research on facial emotion expression has mostly focused on emotion recognition, assuming that a small number of discrete emotions is elicited and expressed via prototypical facial muscle configurations as captured in still photographs. These are expected to be recognized by observers, presumably via template matching. In contrast, appraisal theories of emotion propose a more dynamic approach, suggesting that specific elements of facial expressions are directly produced by the result of certain appraisals and predicting the facial (...) patterns to be expected for certain appraisal configurations. This approach has recently been extended to emotion perception, claiming that observers first infer individual appraisals and only then make categorical emotion judgments based on the estimated appraisal patterns, using semantic inference rules. Here we report two related studies to empirically investigate the facial action unit configurations that are used by actors to convey specific emotions in short affect bursts and to examine to what extent observers can infer a person’s emotions from the predicted facial expression configurations. The results show that 1) professional actors use many of the predicted facial action unit patterns to enact systematically specified appraisal outcomes in a realistic scenario setting, and 2) naïve observers infer the respective emotions based on highly similar facial movement configurations with a degree of accuracy comparable to earlier research findings. Based on estimates of underlying appraisal criteria for the different emotions we conclude that the patterns of facial action units identified in this research correspond largely to prior predictions and encourage further research on appraisal-driven expression and inference. (shrink)

In this article, we review empirical evidence regarding the relationship between facial expression and emotion during infancy. We focus on differential emotions theory’s view of this relationship because of its theoretical and methodological prominence. We conclude that current evidence fails to support its proposal regarding a set of pre-specified facial expressions that invariably reflect a corresponding set of discrete emotions in infants. Instead, the relationship between facial expression and emotion appears to be more complex. Some (...) facial expressions may have different meanings in infants than in children and adults. In addition, nonemotion factors may sometimes lead to the production of “emotional” facial expressions. We consider alternative perspectives on the nature of emotion and emotional expression in infancy with particular focus on differentiation and dynamical systems approaches. (shrink)

Following Yik and Russell (1999) a judgement paradigm was used to examine to what extent differential accuracy of recognition of facial expressions allows evaluation of the well-foundedness of different theoretical views on emotional expression. Observers judged photos showing facial expressions of seven emotions on the basis of: (1) discrete emotion categories; (2) social message types; (3) appraisal results; or (4) action tendencies, and rated their confidence in making choices. Emotion categories and appraisals were judged significantly more accurately (...) and confidently than messages or action tendencies. These results do not support claims of primacy for message or action tendency views of facial expression. Based on a componential model of emotion it is suggested that judges can infer components from categories and vice versa. (shrink)

Automatic facial expression recognition has now advanced to the point that we are able to apply it to spontaneous expressions. The automated tools enable new research activity in cognitive neuroscience, psychiatry, education, human–machine communication, and human social dynamics. Moreover, automated facial expression analysis enables investigations into facial expression dynamics that were previously intractable by human coding because of the time required to code intensity changes. This article provides an overview on the state of the (...) art in computer vision approaches to facial expression recognition, including methods for characterizing expression dynamics. It then discusses behavioral studies that have employed automatic facial expression recognition to learn new information about the relationships of facial expression to internal state, and reviews the first generation of applications in learning and education that take advantage of the real-time expression signal. (shrink)

Facial expressions are a vital way for humans to show their perceived emotions. It is convenient for detecting and recognizing expressions or micro-expressions by annotating a lot of data in deep learning. However, the study of video-based expressions or micro-expressions requires that coders have professional knowledge and be familiar with action unit coding, leading to considerable difficulties. This paper aims to alleviate this situation. We deconstruct facial muscle movements from the motor cortex and systematically sort out the relationship (...) among facial muscles, AU, and emotion to make more people understand coding from the basic principles: We derived the relationship between AU and emotion based on a data-driven analysis of 5,000 images from the RAF-AU database, along with the experience of professional coders.We discussed the complex facial motor cortical network system that generates facial movement properties, detailing the facial nucleus and the motor system associated with facial expressions.The supporting physiological theory for AU labeling of emotions is obtained by adding facial muscle movements patterns.We present the detailed process of emotion labeling and the detection and recognition of AU.Based on the above research, the video's coding of spontaneous expressions and micro-expressions is concluded and prospected. (shrink)