Facial feedback hypotheses: Evidence, implications, and directions

Botulinum toxin-induced facial muscle paralysis affects amygdala responses to the perception of emotional expressions: preliminary findings from an A-B-A design

BACKGROUND

It has long been suggested that feedback signals from facial muscles influence emotional experience. The recent surge in use of botulinum toxin (BTX) to induce temporary muscle paralysis offers a unique opportunity to directly test this "facial feedback hypothesis." Previous research shows that the lack of facial muscle feedback due to BTX-induced paralysis influences subjective reports of emotional experience, as well as brain activity associated with the imitation of emotional facial expressions. However, it remains to be seen whether facial muscle paralysis affects brain activity, especially the amygdala, which is known to be responsive to the perception of emotion in others. Further, it is unknown whether these neural changes are permanent or whether they revert to their original state after the effects of BTX have subsided. The present study sought to address these questions by using functional magnetic resonance imaging to measure neural responses to angry and happy facial expressions in the presence or absence of facial paralysis.

RESULTS

Consistent with previous research, amygdala activity was greater in response to angry compared to happy faces before BTX treatment. As predicted, amygdala activity in response to angry faces was attenuated when the corrugator/procerus muscles were paralyzed via BTX injection but then returned to its original state after the effects of BTX subsided. This preliminary study comprises a small sample size and no placebo condition; however, the A-B-A design affords the present sample to serve as its own control.

CONCLUSIONS

The current demonstration that amygdala responses to facial expressions were influenced by facial muscle paralysis offers direct neural support for the facial feedback hypothesis. Specifically, the present findings offer preliminary causal evidence that amygdala activity is sensitive to facial feedback during the perception of the facial expressions of others. More broadly, these data confirm the utility of using BTX to address the effect of facial feedback on neural responses associated with the perception, in addition to the experience or expression of emotion.

Facial expressions and autonomous nervous system responses elicited by tasting different juices

The aim of this study was to get a better understanding of reactions elicited by the taste of foods using the example of different juices. The reactions investigated were the rating behavior of self-reported spontaneous liking, various autonomous nervous system (ANS) responses and implicit as well as explicit facial expressions. Therefore, the following four hypotheses were tested: 1) Different sensory stimuli of juices elicit different ANS responses. 2) Differences in facial expressions elicited by sensory stimuli of juices used in an implicit and explicit measurement approach can be detected by using FaceReader 5. 3) Self-reported liking is correlated with the measured ANS parameters and the elicited facial expressions. 4) The measured ANS parameters, facial expressions and self-reported liking allow identical differentiations between samples. Skin conductance level (SCL), skin temperature (ST), heart rate (HR), pulse volume amplitude (PVA) and the facial expressions of 81 participants were analyzed during and shortly after tasting juice samples (implicit measurement approach). Additionally, participants were asked to show how much they liked the tasted sample with an intentional facial expression (explicit measurement approach). Banana, grapefruit, mixed vegetable, orange and sauerkraut juices were used as sensory stimuli. The juices elicited significant differences in SCL and PVA responses and intensities of several facial expressions. For these parameters a moderate correlation with self-reported liking was found, allowing a differentiation between liked, disliked and neutral rated samples. The results show that self-reported liking cannot simply be explained by the measured ANS and implicit facial expression parameters, instead providing different information. Significant differences in facial expressions between the implicit and explicit approach were observed. In the implicit approach participants showed hardly any positive emotions when tasting samples they liked, whereas in the explicit approach they displayed a high degree of positive emotions. In both cases negative emotions were shown more intensely for disliked samples.

The perception and mimicry of facial movements predict judgments of smile authenticity

The mechanisms through which people perceive different types of smiles and judge their authenticity remain unclear. Here, 19 different types of smiles were created based on the Facial Action Coding System (FACS), using highly controlled, dynamic avatar faces. Participants observed short videos of smiles while their facial mimicry was measured with electromyography (EMG) over four facial muscles. Smile authenticity was judged after each trial. Avatar attractiveness was judged once in response to each avatar’s neutral face. Results suggest that, in contrast to most earlier work using static pictures as stimuli, participants relied less on the Duchenne marker (the presence of crow’s feet wrinkles around the eyes) in their judgments of authenticity. Furthermore, mimicry of smiles occurred in the Zygomaticus Major, Orbicularis Oculi, and Corrugator muscles. Consistent with theories of embodied cognition, activity in these muscles predicted authenticity judgments, suggesting that facial mimicry influences the perception of smiles. However, no significant mediation effect of facial mimicry was found. Avatar attractiveness did not predict authenticity judgments or mimicry patterns.

Biting versus chewing: eating style and social aggression in children

Does biting food lead to aggressive behavior? An experimental study is reported where children ages 6-10 (n = 12) were served chicken either on-the-bone or pre-cut in bite-size pieces. When children ate on-the-bone chicken, they exhibited more aggressive behavior than pre-cut, boneless chicken. For example, children were more likely to violate the counselor's instructions by leaving the eating area after eating on-the-bone chicken compared to kids who ate pre-cut chicken. These findings suggest a connection between how children eat and how they behave. This could have implications for developmental psychologists as well as for educators and parents.

More on James and the Physical Basis of Emotion

We first present a reconstruction of James’s theory of emotion (JATE) and then argue for four theses: (a) Despite constructivist elements, James’s views are overall in line with basic emotions theory. (b) JATE does not exclude an influence of emotion on intentional action even in its original formulation; nevertheless, this influence is quite limited. It seems possible, however, to repair this problem of the theory. (c) Cannon’s theory of emotion is a centralized version of JATE that inherits from the latter theory a potentially fatal flaw, the insufficient physiological differentiation of emotions. (d) The core claim of JATE, that emotions are bodily feelings, is very likely false.

Communicating with children in healthcare settings

Children are vulnerable to experiencing stress during clinic visits and hospitalization. Children process information differently than adults due to their cognitive abilities and communication skills. There is paucity of literature on the subject of communicating with children in pediatric settings in India. This article highlights the developmental and theoretical principles which underscore the need for communicating directly with children about their healthcare experiences. Understanding the ongoing interactional influences of developmental perceptions, stress, coping, information processing, parental role, psychological preparation, and the child rights perspective may reinforce the necessity for pediatric caregivers to develop attitudes and skills to communicate with children and their family members in an inclusive and supportive manner. A brief overview of elements influencing the communication process is provided. Practical recommendations for developmentally appropriate, child friendly communication techniques while respecting children's right to participation and expression are highlighted. Collaborating with parents and child development professionals, as well as using relevant educational programs could facilitate clearer child focused communication. Incorporating effective communication practices in pediatric settings could improve the focus on children's holistic health and wellbeing.

Emotional resonance deficits in autistic children

According to some theories imitation, defined as an action resonance mechanism, is deficient in autism. In contrast, other theories (e.g., the "top down control of imitation" hypothesis) state that the problem is not in imitation per se but in the way social cues modulate imitative responses. In this study, 15 high-functioning children with autism and 15 matched controls were tested for their ability to imitate finger movements preceded by neutral and emotional facial expressions (primes) in a stimulus-response compatibility task. Hand movements performed after neutral expressions did not differ between the two groups (i.e., they both showed a normal imitative tendency). However, hand movements performed after emotional expressions significantly differed between the two populations, with controls, but not autistic spectrum disorder (ASD), showing enhanced imitation in the emotional condition. This study supports the view that, in ASD, imitation abilities are spared but they are not modulated according to the emotional and social context.

Undifferentiated facial electromyography responses to dynamic, audio-visual emotion displays in individuals with autism spectrum disorders

We examined facial electromyography (fEMG) activity to dynamic, audio-visual emotional displays in individuals with autism spectrum disorders (ASD) and typically developing (TD) individuals. Participants viewed clips of happy, angry, and fearful displays that contained both facial expression and affective prosody while surface electrodes measured corrugator supercilli and zygomaticus major facial muscle activity. Across measures of average and peak activity, the TD group demonstrated emotion-selective fEMG responding, with greater relative activation of the zygomatic to happy stimuli and greater relative activation of the corrugator to fearful stimuli. In contrast, the ASD group largely showed no significant differences between zygomatic and corrugator activity across these emotions. There were no group differences in the magnitude and timing of fEMG response in the muscle congruent to the stimuli. This evidence that fEMG responses in ASD are undifferentiated with respect to the valence of the stimulus is discussed in light of potential underlying neurobiological mechanisms.

Emotion regulation through execution, observation, and imagery of emotional movements

According to Damasio's somatic marker hypothesis, emotions are generated by conveying the current state of the body to the brain through interoceptive and proprioceptive afferent input. The resulting brain activation patterns represent unconscious emotions and correlate with subjective feelings. This proposition implies a corollary that the deliberate control of motor behavior could regulate feelings. We tested this possibility, hypothesizing that engaging in movements associated with a certain emotion would enhance that emotion and/or the corresponding valence. Furthermore, because motor imagery and observation are thought to activate the same mirror-neuron network engaged during motor execution, they might also activate the same emotional processing circuits, leading to similar emotional effects. Therefore, we measured the effects of motor execution, motor imagery and observation of whole-body dynamic expressions of emotions (happiness, sadness, fear) on affective state. All three tasks enhanced the corresponding affective state, indicating their potential to regulate emotions.

Emotional regulation impairments following severe traumatic brain injury: an investigation of the body and facial feedback effects

The object of this study was to evaluate the combined effect of body and facial feedback in adults who had suffered from a severe traumatic brain injury (TBI) to gain some understanding of their difficulties in the regulation of negative emotions. Twenty-four participants with TBI and 28 control participants adopted facial expressions and body postures according to specific instructions and maintained these positions for 10 s. Expressions and postures entailed anger, sadness, and happiness as well as a neutral (baseline) condition. After each expression/posture manipulation, participants evaluated their subjective emotional state (including cheerfulness, sadness, and irritation). TBI participants were globally less responsive to the effects of body and facial feedback than control participants, F(1,50) = 5.89, p = .02, η(2) = .11. More interestingly, the TBI group differed from the Control group across emotions, F(8,400) = 2.51, p = .01, η(2) = .05. Specifically, participants with TBI were responsive to happy but not to negative expression/posture manipulations whereas control participants were responsive to happy, angry, and sad expression/posture manipulations. In conclusion, TBI appears to impair the ability to recognize both the physical configuration of a negative emotion and its associated subjective feeling.

Impairments in social cognition following severe traumatic brain injury

Severe traumatic brain injury (TBI) leads to physical, neuropsychological, and emotional deficits that interfere with the individual’s capacity to return to his or her former lifestyle. This review focuses on social cognition, that is, the capacity to attend to, recognize and interpret interpersonal cues that guide social behavior. Social cognition entails ‘‘hot’’ processes, that is, emotion perception and emotional empathy and ‘‘cold’’ processes, that is, the ability to infer the beliefs, feelings, and intentions of others (theory of mind: ToM) to see their point of view (cognitive empathy) and what they mean when communicating (pragmatic inference). This review critically examines research attesting to deficits in each of these domains and also examines evidence for theorized mechanisms including specific neural networks, the role of simulation, and non-social cognition. Current research is hampered by small, heterogeneous samples and the inherent complexity of TBI pathology. Nevertheless, there is evidence that facets of social cognition are impaired in this population. New assessment tools to measure social cognition following TBI are required that predict everyday social functioning. In addition, research into remediation needs to be guided by the growing empirical base for understanding social cognition that may yet reveal how deficits dissociate following TBI.

Reversal Without Remapping

The “cognitive revolution” in psychology is often framed as a departure from associationist principles rooted in animal learning research, yet it is clear that these principles have immediate relevance for contemporary questions in cognitive and social psychology. Intuitions about the consequences of learning procedures can easily be misleading, making these principles particularly important. To illustrate this point, we identified recent examples of studies applying a particular learning paradigm—response-reversal training—to the study of three different psychological problems (e.g., why objects in the right side of space are preferred to those in the left in right-handed people). The strategy of each study was to alter a typically encountered contingency once in the laboratory, in order to reverse a hypothesized learned response. Yet, contrary to intuitions, we demonstrate that behavior changes can be observed without the reversal of a prior association. Further, many different associative changes can underlie response reversals. We focus on these examples of response-reversal training, but our broader aim is to help connect the animal learning literature to problems in cognitive and social psychology in an effort to strengthen the inferences that might be drawn about learned associations in these contexts.

Depression in cultural context: "Chinese somatization," revisited

We have presented a view of culture and mental health that builds on work in cultural psychiatry, anthropology, and cultural psychology, and applied it to research on culture and depression. In particular, we have returned to the well-known topic of Chinese somatization. A culture–mind–brain approach to these questions helps us think about them in a way that points toward new research. We have applied this approach to thinking about a single set of questions, relevant to a single (DSM-based) diagnosis, in a single cultural group. The potential, however, is to rethink how we conceptualize mental health in ways consistent with cultural psychiatry’s general perspective over the past several decades, while incorporating rather than rejecting the many recent advances in brain and behavior sciences. In so doing, we gain a more expanded and nuanced view of the global landscape of mental health, accompanied by a more expanded and nuanced view of individual patients.

Mimicry of Dynamic Emotional and Motor-Only Stimuli

Simple reciprocal matching behaviors, such as facial mimicry, appear fundamental to social development and interpersonal processes. Identifying mechanisms and moderators of these reactions to others' behaviors is thus important to understanding basic social–emotional functioning and specific clinical syndromes. This experiment extends early electromyographic (EMG) research (Berger & Hadley, 1975) to explore whether rapid, subtle mimicry involves a general motor-matching mechanism (e.g., the mirror neuron system) or if it is related solely to emotional processes. The EMG measured responses to short, dynamic videos of smiling, scowling, stuttering, and arm wrestling. Although mimicry of emotional stimuli was greater than to nonemotional stimuli, participants matched both nonemotional mouth movements and facial expressions of emotions. Mimicry of arm motions was not significant. Individuals' levels of mimicry of emotional and nonemotional were positively correlated. Findings suggest that both motor and affective processes are involved in producing rapid mimetic reactions to dynamic stimuli.

How emotions expressed by adults' faces affect the desire to eat liked and disliked foods in children compared to adults

The aim of this study was to determine whether or not pleasure, neutrality, and disgust expressed by eaters in photographs could affect the desire to eat food products to a greater extent in children than in adults. Children of 5 and 8 years of age, as well as adults, were presented with photographs of liked and disliked foods. These foods were presented either alone or with an eater who expressed three different emotions: pleasure, neutrality, or disgust. Results showed that, compared with food presented alone, food presented with a pleasant face increased the desire to eat disliked foods, particularly in children, and increased the desire to eat liked foods only in the 5-year-old children. In contrast, with a disgusted face, the desire to eat the liked foods decreased in all participants, although to a greater extent in children, while it had no effect on the desire to eat the disliked foods. Finally, food presented with a neutral face also increased and decreased the desire to eat disliked and liked foods, respectively, and in each case more for the 5-year-olds than for the older participants. In sum, the facial expressions of others influence the desire to eat liked and disliked foods and, to a greater extent, in younger children.

The Simulation of Smiles (SIMS) model: Embodied simulation and the meaning of facial expression

Recent application of theories of embodied or grounded cognition to the recognition and interpretation of facial expression of emotion has led to an explosion of research in psychology and the neurosciences. However, despite the accelerating number of reported findings, it remains unclear how the many component processes of emotion and their neural mechanisms actually support embodied simulation. Equally unclear is what triggers the use of embodied simulation versus perceptual or conceptual strategies in determining meaning. The present article integrates behavioral research from social psychology with recent research in neurosciences in order to provide coherence to the extant and future research on this topic. The roles of several of the brain's reward systems, and the amygdala, somatosensory cortices, and motor centers are examined. These are then linked to behavioral and brain research on facial mimicry and eye gaze. Articulation of the mediators and moderators of facial mimicry and gaze are particularly useful in guiding interpretation of relevant findings from neurosciences. Finally, a model of the processing of the smile, the most complex of the facial expressions, is presented as a means to illustrate how to advance the application of theories of embodied cognition in the study of facial expression of emotion.

Examination of the passive facial feedback hypothesis using an implicit measure: with a furrowed brow, neutral objects with pleasant primes look less appealing

98 undergraduates (54 men, 44 women) participated in an experiment to examine whether having an artificially furrowed brow would have an effect on participants' subjective impression of perceived targets. An elastic adhesive bandage was either stretched to create furrows on the brow when it retracted, or not stretched so as to avoid creating wrinkles. While wearing the bandages, the participants rated their impressions of neutral targets preceded by agreeable, disagreeable, or neutral primes in a modified Affect Misattribution Procedure. The results showed that participants with artificially furrowed brows tended to rate the neutral targets preceded by agreeable primes less favorably than did the control participants, while both groups rated similarly the targets preceded by disagreeable primes.

Work exhaustion in information technology professionals

As the role of information technology (IT) in business grows and IT users become more technologically dependent, the IT professional is increasingly expected to work with individuals from other areas of the organization. Dealing with customers, either internal or external, brings the expectation that one will conform to societal, occupational, or organizational norms regarding the display of emotion. This paper examines the impact of emotional display expectations on work exhaustion in IT professionals. We find that the method that one uses to manage emotional reactions in the workplace impacts work exhaustion. Surface acting shows a strong, positive association with work exhaustion while deep acting shows no such relationship. We find that the perception of emotional display rules in the workplace affects the use of emotional management strategies, termed deep acting and surface acting. We also find that the necessity of dealing with other's emotions impacts the level of display rule expectations. The findings of this study offer important contributions to theory by exploring emotional labor expectations of IT professionals. This study also offers suggestions to management to help alleviate the stresses associated with common workplace interactions.

Time perception in response to ashamed faces in children and adults

The present study investigated the effect of the perception of faces expressing shame on time perception in children aged 5 and 8 years, as well as in adults, as a function of their ability to recognize this emotional expression. The participants' ability to recognize the expression of shame among faces expressing different emotions was tested. They were then asked to perform a temporal bisection task involving both neutral and ashamed faces. The results showed that, from the age of 8 years, the participants who recognized the facial expressions of shame underestimated their presentation time compared to that of neutral faces. In contrast, no time distortion was observed in the children who did not recognize the ashamed faces or in those younger children who did recognize them. The results are discussed in terms of self-conscious emotions which develop to involve an attentional mechanism.

Emotion and Regulation are One!

Emotions are foremost self-regulating processes that permit rapid responses and adaptations to situations of personal concern. They have biological bases and are shaped ontogenetically via learning and experience. Many situations and events of personal concern are social in nature. Thus, social exchanges play an important role in learning about rules and norms that shape regulation processes. I argue that (a) emotions often are actively auto-regulating—the behavior implied by the emotional reaction bias to the eliciting event or situation modifies or terminates the situation; (b) certain emotion components are likely to habituate dynamically, modifying the emotional states; (c) emotions are typically intra- and interpersonal processes at the same time, and modulating forces at these different levels interact; (d) emotions are not just regulated—they regulate. Important conclusions of my arguments are that the scientific analysis of emotion should not exclude regulatory processes, and that effortful emotion regulation should be seen relative to a backdrop of auto-regulation and habituation, and not the ideal notion of a neutral baseline. For all practical purposes unregulated emotion is not a realistic concept.

Contagious yawning in autistic and typical development

The authors tested susceptibility to contagious yawning in 120 children, 1-6 years, to identify the time course of its emergence during development. Results indicated a substantial increase in the frequency of contagious yawning at 4 years. In a second study, the authors examined contagious yawning in 28 children with autism spectrum disorders (ASD), 6-15 years. Children with ASD showed diminished susceptibility to contagious yawning compared with 2 control groups matched for mental and chronological age, respectively. In addition, children diagnosed with Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS) a milder variant of autism, were more susceptible to contagious yawning than were children diagnosed with full Autistic Disorder. The authors explore the implications of these findings for theories about the development of mimicry and emotional contagion.

How Does Facial Feedback Modulate Emotional Experience?

Contracting muscles involved in facial expressions (e.g. smiling or frowning) can make emotions more intense, even when unaware one is modifying expression (e.g. Strack, Martin, & Stepper, 1988). However, it is unresolved whether and how inhibiting facial expressions might weaken emotional experience. In the present study, 142 participants watched positive and negative video clips while either inhibiting their facial expressions or not. When hypothesis awareness and effects of distraction were experimentally controlled, inhibiting facial expressions weakened some emotional experiences. These findings provide new insight into ways that inhibition of facial expression can affect emotional experience: the link is not dependent on experimental demand, lay theories about connections between expression and experience, or the distraction involved in inhibiting one's expressions.

Embodied emotion modulates neural signature of performance monitoring

Background

Recent research on the “embodiment of emotion” implies that experiencing an emotion may involve perceptual, somatovisceral, and motor feedback aspects. For example, manipulations of facial expression and posture appear to induce emotional states and influence how affective information is processed. The present study investigates whether performance monitoring, a cognitive process known to be under heavy control of the dopaminergic system, is modulated by induced facial expressions. In particular, we focused on the error-related negativity, an electrophysiological correlate of performance monitoring.

Methods/Principal Findings

During a choice reaction task, participants held a Chinese chop stick either horizontally between the teeth (“smile” condition) or, in different runs, vertically (“no smile”) with the upper lip. In a third control condition, no chop stick was used (“no stick”). It could be shown on a separate sample that the facial feedback procedure is feasible to induce mild changes in positive affect. In the ERP sample, the smile condition, hypothesized to lead to an increase in dopaminergic activity, was associated with a decrease of ERN amplitude relative to “no smile” and “no stick” conditions.

Conclusion

Embodying emotions by induced facial expressions leads to a changes in the neural correlates of error detection. We suggest that this is due to the joint influence of the dopaminergic system on positive affect and performance monitoring.

Embodied and Disembodied Emotion Processing: Learning From and About Typical and Autistic Individuals

Successful social functioning requires quick and accurate processing of emotion and generation of appropriate reactions. In typical individuals, these skills are supported by embodied processing, recruiting central and peripheral mechanisms. However, emotional processing is atypical in individuals with autism spectrum disorder (ASD). Individuals with ASD show deficits in recognition of briefly presented emotional expressions. They tend to recognize expressions using rule-based, rather than template, strategies. Individuals with ASD also do not spontaneously and quickly mimic emotional expressions, unless the task encourages engagement. When processing emotional scenes, ASD individuals show atypical basic motivational responses, despite intact ability to verbally determine stimulus valence. We discuss how these findings highlight the contribution of both embodied and disembodied mechanisms to typical and atypical emotional functioning.

Facial feedback mechanisms in autistic spectrum disorders

Facial feedback mechanisms of adolescents with Autistic Spectrum Disorders (ASD) were investigated utilizing three studies. Facial expressions, which became activated via automatic (Studies 1 and 2) or intentional (Study 2) mimicry, or via holding a pen between the teeth (Study 3), influenced corresponding emotions for controls, while individuals with ASD remained emotionally unaffected. Thus, individuals with ASD do not experience feedback from activated facial expressions as controls do. This facial feedback-impairment enhances our understanding of the social and emotional lives of individuals with ASD.

Imitation of facial expressions in schizophrenia

Diminished facial expressivity is a common feature of schizophrenia that interferes with effective interpersonal communication. This study was designed to determine if real-time visual feedback improved the ability of patients with schizophrenia to imitate and produce modeled facial expressions. Twenty patients with schizophrenia and 10 controls viewed static images of facial expressions and were asked to imitate them. Half of the images were imitated with the use of a mirror and half were imitated without the use of a mirror. In addition, we examined whether practice in imitating and producing expressions improved the ability of participants to generate facial expressions on their own, without the aid of a model or mirror. Participants' facial expressions were photographed with a digital camera and each was rated for accuracy in producing characteristic facial expressions. Patients with schizophrenia were less accurate in imitating and producing facial expressions than controls, and real-time visual feedback did not improve accuracy in either group. Preliminary findings suggest that exposure to model expressions and practice in generating these expressions can improve the accuracy of certain posed expressions in schizophrenia.

Embodied temporal perception of emotion

The role of embodiment in the perception of the duration of emotional stimuli was investigated with a temporal bisection task. Previous research has shown that individuals overestimate the duration of emotional, compared with neutral, faces (S. Droit-Volet, S. Brunot, & P. M. Niedenthal, 2004). The authors tested a role for embodiment in this effect. Participants estimated the duration of angry, happy, and neutral faces by comparing them to 2 durations learned during a training phase. Experimental participants held a pen in their mouths so as to inhibit imitation of the faces, whereas control participants could imitate freely. Results revealed that participants overestimated the duration of emotional faces relative to the neutral faces only when imitation was possible. Implications for the role of embodiment in emotional perception are discussed.

When the social mirror breaks: deficits in automatic, but not voluntary, mimicry of emotional facial expressions in autism

Humans, infants and adults alike, automatically mimic a variety of behaviors. Such mimicry facilitates social functioning, including establishment of interpersonal rapport and understanding of other minds. This fundamental social process may thus be impaired in disorders such as autism characterized by socio-emotional and communicative deficits. We examined automatic and voluntary mimicry of emotional facial expression among adolescents and adults with autistic spectrum disorders (ASD) and a typical sample matched on age, gender and verbal intelligence. Participants viewed pictures of happy and angry expressions while the activity over their cheek and brow muscle region was monitored with electromyography (EMG). ASD participants did not automatically mimic facial expressions whereas the typically developing participants did. However, both groups showed evidence of successful voluntary mimicry. The data suggest that autism is associated with an impairment of a basic automatic social-emotion process. Results have implications for understanding typical and atypical social cognition.

THE EVOLUTION AND FUNCTIONS OF LAUGHTER AND HUMOR: A SYNTHETIC APPROACH

A number of recent hypotheses have attempted to explain the ultimate evolutionary origins of laughter and humor. However most of these have lacked breadth in their evolutionary frameworks while neglecting the empirical existence of two distinct types of laughter--Duchenne and non-Duchenne--and the implications of this distinction for the evolution of laughter as a signal. Most of these hypotheses have also been proposed in relative isolation of each other and remain disjointed from the relevant empirical literature. Here we attempt to remedy these shortcomings through a synthesis of previous laughter and humor research followed by (i) a reevaluation of this research in light of theory and data from several relevant disciplines, and (ii) the proposal of a synthetic evolutionary framework that takes into account phylogeny and history as well as proximate mechanisms and adaptive significance. We consider laughter to have been a preadaptation that was gradually elaborated and co-opted through both biological and cultural evolution. We hypothesize that Duchenne laughter became fully ritualized in early hominids between 4 and 2 mya as a medium for playful emotional contagion. This mechanism would have coupled the emotions of small hominid groups and promoted resource-building social play during the fleeting periods of safety and satiation that characterized early bipedal life. We further postulate that a generalized class of nonserious social incongruity would have been a reliable indicator of such safe times and thereby came to be a potent distal elicitor of laughter and playful emotion. This class of stimuli had its origins in primate social play and was the foundation for formal human humor. Within this framework, Duchenne laughter and protohumor were well established in the hominid biobehavioral repertoire when more cognitively sophisticated traits evolved in the hominid line between 2 mya and the present. The prior existence of laughter and humor allowed them to be co-opted for numerous novel functions, and it is from this process that non-Duchenne laughter and the "dark side" of laughter emerged. This perspective organizes the diversified forms and functions that characterize laughter and humor today and clarifies when and how laughter and humor evolved during the course of human evolution.

Dismissing-avoidant pattern of attachment and mimicry reactions at different levels of information processing

Individuals with a dismissing-avoidant pattern of attachment are assumed to repress anxiety-related signals, a disposition hypothesized to interfere with facial mimicry and emotional contagion. Further, they are assumed to have one internal working model associated with anxiety, operating out of awareness at early, automatic stages of information processing, and another positive model operating at later, cognitively controlled stages of processing. The main aim of the present investigation was to compare facial mimicry in dismissing-avoidant and non-dismissing subjects at different levels of information processing. Pictures of happy and angry faces were exposed to 61 subjects at three different exposure times (17, 56, and 2,350 ms) in order to elicit facial muscle reactions, first at automatic levels and then at a more controlled levels. Corrugator activity ("frowning muscles") represented negative emotions and zygomaticus activity ("smiling muscles") positive emotions. The dismissing-avoidant subjects scored significantly lower on emotional empathy than the non-dismissing subjects. At the automatic level the dismissing-avoidant subjects showed "normal" corrugator responses (negative emotions) upon exposure to angry faces. At the cognitively controlled level of processing (2,350 ms) a significant interaction effect was shown between Faces x Muscles x Attachment pattern. The dismissing-avoidant subjects showed no corrugator response and an increased zygomaticus response ("smiling reaction") to the angry face, whereas the non-dismissing subjects reacted with a significant mimicking reaction. The dismissing-avoidant subjects' tendency to "smiling" in response to the angry face at the controlled level (2,350 ms) may be interpreted as a repression of their earlier, automatically evoked (56 ms) negative emotional reaction.