Perceived unpleasantness and facial reactions to auditory stimuli

This study examined whether facial electromyographic (EMG) reactions differentiate between identical tone stimuli which subjects perceive as differently unpleasant. Subjects were repeatedly exposed to a 1000 Hz 75 dB tone stimulus while their facial EMG from the corrugator and zygomatic muscle regions were measured. Skin conductance and heart rate responses were also measured. The subjects rated the unpleasantness of the stimulus and based on these ratings they were divided into two groups, High and Low in perceived unpleasantness. As predicted the facial EMG activity reflected the perceived unpleasantness. That is, the High group but not the Low group reacted with an increased corrugator response. The autonomic data, on the other hand, did not differ between groups. The results are consistent with the proposition that the facial muscles function as a readout system for emotional reactions and that facial muscle activity is intimately related to the experiential level of the emotional response system.     

Fear of snakes and facial reactions: A case of rapid emotional responding

The aim of the present study was to explore how rapid emotional responses are manifested as facial electromyographic (EMG) reactions when people with explicit fear of snakes are exposed to their fear relevant stimuli. Fifty-six subjects, high or low in fear of snakes, were exposed to pictures of snakes and flowers while facial EMG activity from the corrugator supercilii and the zygomatic major muscle regions was recorded. Measures of autonomic activity and ratings of the stimuli were also collected. Pictures of snakes evoked a rapid corrugator supercilii muscle reaction which was larger in the High fear group as early as 500ms after stimulus onset. The High fear group also rated snakes as more unpleasant and displayed larger skin conductance responses (SCRs) and increased heart rate (HR) when exposed to snakes. Pictures of flowers tended to evoke increased zygomatic major muscle activity which did not differ among the groups. The present results demonstrate that the facial EMG technique is sensitive enough to detect rapidly evoked negative emotional reactions. The results support the hypothesis that people high in fear of snakes are disposed to react very rapidly with a negative emotional response to their fear relevant stimuli.     

Facial EMG reactions to facial expressions: A case of facial emotional contagion?

The purpose of this study is to explore whether subjects exposed to stimuli of facial expressions respond with facial electromyographic (EMG) reactions consistent with the hypothesis that facial expressions are contagious. This study further examines whether males and females differ in facial EMG intensity. Two experiments demonstrated that subjects responded with facial EMG activity over the corrugator supercilii, the zygomatic major , the lateral frontalis , the depressor supercilii , and the levator labii muscle regions to stimuli of sad, angry, fearful, surprised, disgusted and happy faces, that, to large extent, were consistent with the hypothesis that facial expressions are contagious. Aspects of gender differences reported in earlier studies were found, indicating a tendency for females to respond with more pronounced facial EMG intensity.     

The facial pattern of disgust, appetence, excited joy and relaxed joy: an improved facial EMG study

The purpose of the study was to investigate the facial muscle pattern of disgust in comparison to appetence and joy, using an improved facial EMG method. We analyzed the activity of nine facial muscles in forty healthy subjects. The subject group was randomly divided into two groups (oversaturated vs. hungry) of ten women and ten men each. Four different emotions (disgust, appetence, excited-joy and relaxed-joy) were induced by showing pictures from the IAPS. Pre-visible facial muscle activity was measured with a new facial EMG. A Visual Analog Scale (VAS) was established. Disgust is represented by a specific facial muscle pattern involving M.corrugator and M.orbicularis oculi, clearly distinguishing it from the facial patterns of appetence and joy. The intensity of disgust is stronger in a state of hunger than under oversaturation and is altogether stronger in females than in males. Our findings indicate the possibility to explore the entire emotion system successfully through a state-of-the-art psychophysiological method like our EMG device.     

Sex and menstrual cycle differences in the habituation and spontaneous recovery of the electrodermal orienting reaction

Sex and menstrual cycle differences have been widely observed in electrodermal activity. The aim of this study was to investigate these differences in the electrodermal orienting reaction employing a habituation-spontaneous recovery procedure. According to previous research it was predicted that men and preovulatory women should show higher electrodermal responses, higher skin conductance levels, and slower habituation rates. Thirty-two subjects (16 males and 16 females) were presented with two series of tones, 10 in the first series and eight in the second, with a 4-min rest period between the two series. Half of the subjects received the same 5-sec tone (80 dB, 1000 Hz) in each presentation while the other half received 80-dB, 5-sec tones which varied randomly in frequency (100, 500, 1000 Hz). Women were divided into two groups; preovulatory (n = 7) and postovulatory (n = 8) according to their answers to a retrospective questionnaire. The mean response amplitude was higher in the group of males, who habituated later than females. Postovulatory women showed lower orienting reactions in the first series, and habituated faster than did preovulatory women in the two series. There were neither significant differences between males and females, nor between preovulatory and postovulatory women in tonic conductance levels. These results support the existence of greater electrodermal reactivity in males and in preovulatory women.     

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.     

Speech anxiety and rapid emotional reactions to angry and happy facial expressions

The aim was to explore whether people high as opposed to low in speech anxiety react with a more pronounced differential facial response when exposed to angry and happy facial stimuli. High and low fear participants were selected based on their scores on a fear of public speaking questionnaire. All participants were exposed to pictures of angry and happy faces while facial electromyographic (EMG) activity from the Corrugator supercilii and the Zygomaticus major muscle regions was recorded. Skin conductance responses (SCR), heart rate (HR) and ratings were also collected. Participants high as opposed to low in speech anxiety displayed a larger differential corrugator responding, indicating a larger negative emotional reaction, between angry and happy faces. They also reacted with a larger differential zygomatic responding, indicating a larger positive emotional reaction, between happy and angry faces. Consistent with the facial reaction patterns, the high fear group rated angry faces as more unpleasant and as expressing more disgust, and further rated happy faces as more pleasant. There were no differences in SCR or HR responding between high and low speech anxiety groups. The present results support the hypothesis that people high in speech anxiety are disposed to show an exaggerated sensitivity and facial responsiveness to social stimuli.     

Facial reactions to facial expressions in subjects high and low in public speaking fear

This study investigated whether subjects high and low in public speaking fear react with different facial electromyographic (EMG) activities when exposed to negative and positive social stimuli. A High-fear and Low-fear group were selected by help of a questionnaire and were exposed to slides of angry and happy faces while facial-EMG from the corrugator and zygomatic muscle regions were measured. The subjects also rated the stimuli on different emotional dimensions. Consistent with earlier research it was found that Low fear subjects reacted with increased corrugator activity to angry faces and increased zygomatic activity to happy faces. The High fear group, on the other hand, did not distinguish between angry and happy faces. Rating data indicated that the High fear group perceived angry faces as being emotionally more negative. The present results are consistent with earlier studies, indicating that the facial-EMG technique is sensitive to detect differential responding among clinical interesting groups, such as people suffering from social fears.     

Facial reactions to fear-relevant stimuli for subjects high and low in specific fear

This study was performed to investigate whether subjects high and low in fear of snakes react with different facial electromyographic (EMG) responses when exposed to snakes. Two groups of subjects were exposed to slides of snakes or flowers. After the experiment they rated their fear of snakes on a questionnaire and based on these ratings they were divided into high and low fear groups. Facial EMG was measured from the corrugator and zygomatic muscle regions. As predicted the high fear group reacted with a facial response interpretable as a negative emotional reaction whereas the low fear group did not. This difference was specific to snakes because high and low groups did not differ in responses to slides of flowers. The results are consistent with the proposition that facial EMG technique is a sensitive tool to distinguish reactions between subjects high and low in specific fears.     

Emotions in Go/NoGo conflicts

On the basis of current emotion theories and functional and neurophysiological ties between the processing of conflicts and errors on the one hand and errors and emotions on the other hand we predicted that conflicts between prepotent Go responses and occasional NoGo trials in the Go/NoGo task would induce emotions. Skin conductance responses (SCRs), corrugator muscle activity, and startle blink responses were measured in three experiments requiring speeded Go responses intermixed with NoGo trials of different relative probability and in a choice reaction experiment serving as a control. NoGo trials affected several of these emotion-sensitive indicators as SCRs and startle blinks were reduced whereas corrugator activity was prolonged as compared to Go trials. From the pattern of findings we suggest that NoGo conflicts are not aversive. Instead, they appear to be appraised as obstructive for the response goal and as less action relevant than Go trials.     

Study of posed emotion in facial EMG asymmetry

37 subjects' facial electromyographic activity at the corrugator and zygomatic muscle regions were recorded while they were posing with happy and sad facial expressions. Analysis showed that the mean value of EMG activity at the left zygomatic muscle region was the highest, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while a happy facial expression was posed. The mean value of EMG activity at the left corrugator muscle region was the highest, followed by those for the right corrugator, left zygomatic, and right zygomatic muscle regions while a sad facial expression was posed. Further analysis indicated that the power of facial EMG activity on the left side of the face was stronger than on the right side of the face while posing both happy and sad expressions.     

Facial reactions to emotional stimuli: Automatically controlled emotional responses

Based on a model in which the facial muscles can be both automatically/involuntarily controlled and voluntarily controlled by conscious processes, we explore whether spontaneously evoked facial reactions can be evaluated in terms of criteria for what characterises an automatic process. In three experiments subjects were instructed to not react with their facial muscles, or to react as quickly as possible by wrinkling the eyebrows (frowning) or elevating the cheeks (smiling) when exposed to pictures of negative or positive emotional stimuli, while EMG activity was measured from the corrugator supercilii and zygomatic major muscle regions. Consistent with the proposition that facial reactions are automatically controlled, the results showed that the corrugator muscle reaction was facilitated to negative stimuli and the zygomatic muscle reaction was facilitated to positive stimuli. The results further showed that, despite the fact that subjects were required to not react with their facial muscles at all, they could not avoid producing a facial reaction that corresponded to the negative and positive stimuli.     

Electromyographic activity over facial muscle regions can differentiate the valence and intensity of affective reactions

Physiological measures have traditionally been viewed in social psychology as useful only in assessing general arousal and therefore as incapable of distinguishing between positive and negative affective states. This view is challenged in the present report. Sixteen subjects in a pilot study were exposed briefly to slides and tones that were mildly to moderately evocative of positive and negative affect. Facial electromyographic (EMG) activity differentiated both the valence and intensity of the affective reaction. Moreover, independent judges were unable to determine from viewing videotapes of the subjects' facial displays whether a positive or negative stimulus had been presented or whether a mildly or moderately intense stimulus had been presented. In the full experiment, 28 subjects briefly viewed slides of scenes that were mildly to moderately evocative of positive and negative affect. Again, EMG activity over the brow (corrugator supercilia), eye (orbicularis oculi), and cheek (zygomatic major) muscle regions differentiated the pleasantness and intensity of individuals' affective reactions to the visual stimuli even though visual inspection of the videotapes again indicated that expressions of emotion were not apparent. These results suggest that gradients of EMG activity over the muscles of facial expression can provide objective and continuous probes of affective processes that are too subtle or fleeting to evoke expressions observable under normal conditions of social interaction.     

The influence of introversion/extraversion on the skin conductance response to stress and stimulus intensity

A series of studies compared skin conductance level (SCL) for introverts and extraverts during a series of tones varying in both stimulus intensity (SI) and the amount of stress preceding the tones. When a difficult paired-associate task preceded the tones, both groups were about the same for 83 dB tones but extraverts were much higher at 103 dB, introverts failing to show an increase as a function of SI. There were no differences between the two groups following a simple paired-associate task, both groups showing a similar increase with increased SI. Finally, SCL was higher for introverts than extraverts during tones preceded by a rest period, and this was especially true for the early trials and for lower SI (75 and 83 dB compared with 100 and 103 dB). Taken together, these results suggest that SCL is higher for extraverts at higher levels of arousal but that the reverse is true for lower levels of arousal. This relationship is consistent with the theory that introverts have a “weak nervous system” which develops transmarginal or protective inhibition under stress.     

Tone‐affect compatibility with affective stimuli and affective responses

Three experiments examine multimodal integration of tone pitch (high/low), facial expression stimuli (happy/angry), and responses (happy/angry) in a compatibility paradigm. When the participants' task is to imitate facial expressions (Experiment 1), smiles are facilitated by high tones whereas frowns are facilitated by low tones. Experiments 2 and 3 further analyse this effect and show that there is both integration between the tone stimulus and the facial stimulus and between the tone stimulus and the facial response. Results suggest that pitch height is associated with emotion. An interpretation in terms of an embodied cognition approach that emphasizes an interweavement of perception and action is discussed.     

Age-Invariance in the Asymmetry of Stimulus-Evoked Emotional Facial Muscle Activity

This study examined possible effects of aging on the lateralization of stimulus-evoked emotional facial muscle activity. Older participants (mean age 68.4 years) and younger participants (mean age 26.4 years) viewed slides of positive, neutral, or negative emotional content. While participants viewed the slides, bilateral electromyographic (EMG) recordings were obtained from the skin surface over zygomatic and corrugator facial muscles. The participants also made ratings of experienced emotional valence and arousal. Expected patterns of subjective experience and asymmetrical EMG activity were found in response to target stimuli. Greater corrugator muscle activity occurred during presentation of negative stimuli, whereas greater zygomatic muscle activity occurred during presentation of positive stimuli. Consistent with right-hemisphere specialization theories of emotion, left-sided facial EMG activity was consistently greater than that of the right side during presentation of emotional stimuli. However, neither subjective ratings nor EMG patterns showed a significant effect of age group. Such similar patterns of emotional response for the two groups suggest, that the aging process does not produce marked changes in stimulus-evoked emotional experience or in the pattern, magnitude, or lateralization of facial muscle activity associated with emotional states.     

Facial reactions to violent and comedy films: Association with callous–unemotional traits and impulsive aggression

The current study adds to prior research by investigating specific (happiness, sadness, surprise, disgust, anger and fear) and general (corrugator and zygomatic muscle activity) facial reactions to violent and comedy films among individuals with varying levels of callous–unemotional (CU) traits and impulsive aggression (IA). Participants at differential risk of CU traits and IA were selected from a sample of 1225 young adults. In Experiment 1, participants (N?=?82) facial expressions were recorded while they watched violent and comedy films. Video footage of participants' facial expressions was analysed using FaceReader, a facial coding software that classifies facial reactions. Findings suggested that individuals with elevated CU traits showed reduced facial reactions of sadness and disgust to violent films, indicating low empathic concern in response to victims' distress. In contrast, impulsive aggressors produced specifically more angry facial expressions when viewing violent and comedy films. In Experiment 2 (N?=?86), facial reactions were measured by monitoring facial electromyography activity. FaceReader findings were verified by the reduced facial electromyography at the corrugator, but not the zygomatic, muscle in response to violent films shown by individuals high in CU traits. Additional analysis suggested that sympathy to victims explained the association between CU traits and reduced facial reactions to violent films.     

Individual response differences in spider phobia: comparing phobic and non-phobic women of different reactivity levels

In contrast to previous stress research, studies concerning phobic disorders have never systematically investigated individual response differences between phobic participants integrating numerous different response measures. The aim of this article is to clarify the existence of significant individual response differences in psychophysiological responses (e.g., heart rate, skin conductance responses (SCR), corrugator, cortisol), subjective ratings (e.g., valence, arousal), and avoidance behavior in 46 spider phobic and 44 non-phobic women when exposed to 20 phobic and 20 neutral pictures. Previous studies that did not attend to individual response differences showed that, during phobic stimulation, phobic individuals have increased psychophysiological responses (heart rate, SCR, and corrugator responses), more negative valence rating, and more subjective arousal than non-phobic individuals. These results were confirmed by our data. With regard to individual response uniqueness, 1/3-2/3 of spider-phobic women with low responsiveness in heart rate, cortisol, and avoidance behavior were indistinguishable from non-phobic women during phobic stimulation. With SCR, corrugator EMG, and subjective ratings, no individual response uniqueness was found. Based on the findings, exposure therapy might be improved by tailoring interventions to individuals with a therapeutic focus on those psychophysiological measures that show the highest individual responsivity.     

Physiologic reactivity to startling tones in women with posttraumatic stress disorder.

Autonomic and eyeblink reactivity to startling tones were investigated in women with histories of childhood sexual abuse (CSA). Twenty-one women with current posttraumatic stress disorder (PTSD), 23 with lifetime but not current PTSD, and 13 women who never had PTSD listened to 15 95-dB, 500-ms, 1000-Hz tones with a 0-ms rise time while heart rate (HR), skin conductance (SC), and orbicularis oculi electromyogram (EMG) responses were measured. Participants in the current and lifetime PTSD groups produced larger HR responses across tones and showed slower absolute habituation of SC response magnitude compared with the never PTSD group. EMG response magnitudes did not differ among groups. Women with CSA-related PTSD showed increased autonomic reactivity and slower habituation to high-intensity tones similar to that observed in primarily male, combat PTSD samples. This suggests that heightened autonomic responsivity to startling stimuli in PTSD is not gender or event specific.     

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.