Psychophysiological responses as indices of affective dimensions

The startle reflex, facial electromyogram (EMG), and autonomic nervous system responses were examined during imagery varying in affective valence and arousal. Subjects (N= 48) imagined affective situations during tone-cued 8-strials. Startle blink magnitudes were larger and latencies faster during negatively valent than during positively valent conditions and during high-arousal than during low-arousal conditions. Greatest heart rate acceleration and fastest and largest skin conductance responses to startle probes occurred during high-arousal imagery. Zygomatic and orbicularis oculi facial muscle activities were higher during high-arousal imagery, whereas corrugator muscle activity was higher during low-arousal imagery. Zygomatic and corrugator activity also varied with emotional valence. The startle and facial EMG responses are most parsimoniously organized by the negative affect (NA) and positive affect (PA) dimensions, respectively. This NA/PA framework integrates previous research, dimensional theories of emotional behavior, and physiological assessment of pathological emotion.     

Appraisal frames of pleasant and unpleasant pictures alter emotional responses as reflected in self-report and facial electromyographic activity

Emotional pictures elicit responses across experiential, behavioral and physiological systems. The magnitude of these responses can be modulated by altering one's interpretation of emotional stimuli. Previous studies have indicated that appraisal frames affect subsequent interpretations of upcoming stimuli so as to alter self-reported emotions, ERP activity and autonomic responses. No studies to date have examined the effect of appraisal frames on expressive behaviors as measured by facial EMG. This study aims to test the hypothesis that appraisal frames can alter both emotional experience and facial expression and attempts to examine their effect on the temporal unfolding of facial expressions. Participants (N=20) were exposed to 125 pairs of appraisal frames (neutral or negative/positive) followed by neutral, unpleasant, or pleasant pictures reflecting five conditions: unpleasant-negative, unpleasant-neutral, pleasant-positive, pleasant-neutral and neutral-neutral. Results indicate that the unpleasant-negative compared to the unpleasant-neutral condition led to greater self-reported unpleasantness and arousal, as well as greater corrugator activity, and the pleasant-positive compared to the pleasant-neutral condition led to greater self-reported pleasantness and zygomaticus activity; modulation of facial responses became evident 0.5-1.0s after stimulus onset. These results suggest that appraisal frames effectively alter both emotional experience and facial expressions.     

What our eyes tell us about feelings: Tracking pupillary responses during emotion regulation processes

Emotion regulation is essential for adaptive behavior and mental health. Strategies applied to alter emotions are known to differ in their impact on psychological and physiological aspects of the emotional response. However, emotion regulation outcome has primarily been assessed via self‐report, and studies comparing regulation strategies with regard to their peripheral physiological mechanisms are limited in number. In the present study, we therefore aimed to investigate the effects of different emotion regulation strategies on pupil dilation, skin conductance responses, and subjective emotional responses. Thirty healthy females were presented with negative and neutral pictures and asked to maintain or up‐ and downregulate their upcoming emotional responses through reappraisal or distraction. Pupil dilation and skin conductance responses were significantly enhanced when viewing negative relative to neutral pictures. For the pupil, this emotional arousal effect manifested specifically late during the pupillary response. In accordance with subjective ratings, increasing negative emotions through reappraisal led to the most prominent pupil size enlargements, whereas no consistent effect for downregulation was found. In contrast, early peak dilations were enhanced in all emotion regulation conditions independent of strategy. Skin conductance responses were not further modulated by emotion regulation. These results indicate that pupil diameter is modulated by emotional arousal, but is initially related to the extent of mental effort required to regulate automatic emotional responses. Our data thus provide first evidence that the pupillary response might comprise two distinct temporal components reflecting cognitive emotion regulation effort on the one hand and emotion regulation success on the other hand.     

Schizophrenic patients show facial reactions to emotional facial expressions

Facial reactions in schizophrenic patients were assessed via electromyography (EMG) in response to pictures of facial expressions. Male patients and nonpatient controls viewed photographs of positive and negative facial expressions while EMG activity from the corrugator and zygomatic muscle regions was recorded. Both schizophrenic patients and controls exhibited greater zygomatic reactivity in response to positive pictures than in response to negative pictures and greater corrugator reactivity in response to negative pictures than in response to positive pictures. Schizophrenic patients exhibited greater corrugator reactivity than did nonpatient controls. Implications for understanding emotion expression and perception in schizophrenic patients are discussed.     

Addressing the specificity of affective startle modulation: fear versus disgust.

Previous research is equivocal regarding whether startle reflex eyeblink is specifically sensitive to the emotion of fear, or is more generally influenced by the valence dimension of emotion. Thirty-five undergraduate participants (17 male) viewed 60 pictures from five affective categories (pleasant, neutral, fear, disgust-blood, and disgust-other). Bilateral eyeblink EMG responses to acoustic startle probes were assessed during 2/3 of picture presentations, and 1/3 of intertrial intervals. Left corrugator and levator EMG responses to no-startle pictures were also examined. Supporting an emotional valence model of affective startle modulation, the startle potentiation effect was not specific to fear materials. In fact, women, but not men, had larger startles during disgust compared with fear pictures. Both corrugator and levator EMG responses were greater to disgust than fear stimuli. These findings limit the generalizability of corrugator as an index of all negative emotions and extend evidence for the specificity of levator to disgust.     

Electromyographic responses to emotional facial expressions in 6-7year olds: A feasibility study

Preliminary studies have demonstrated that school-aged children (average age 9-10years) show mimicry responses to happy and angry facial expressions. The aim of the present study was to assess the feasibility of using facial electromyography (EMG) as a method to study facial mimicry responses in younger children aged 6-7years to emotional facial expressions of other children. Facial EMG activity to the presentation of dynamic emotional faces was recorded from the corrugator, zygomaticus, frontalis and depressor muscle in sixty-one healthy participants aged 6-7years. Results showed that the presentation of angry faces was associated with corrugator activation and zygomaticus relaxation, happy faces with an increase in zygomaticus and a decrease in corrugator activation, fearful faces with frontalis activation, and sad faces with a combination of corrugator and frontalis activation. This study demonstrates the feasibility of measuring facial EMG response to emotional facial expressions in 6-7year old children.     

Looking at pictures: Affective, facial, visceral, and behavioral reactions

Colored photographic pictures that varied widely across the affective dimensions of valence (pleasant-unpleasant) and arousal (excited-calm) were each viewed for a 6-s period while facial electromyographic (zygomatic and corrugator muscle activity) and visceral (heart rate and skin conductance) reactions were measured. Judgments relating to pleasure, arousal, interest, and emotional state were measured, as was choice viewing time. Significant covariation was obtained between (a) facial expression and affective valence judgments and (b) skin conductance magnitude and arousal ratings. Interest ratings and viewing time were also associated with arousal. Although differences due to the subject's gender and cognitive style were obtained, affective responses were largely independent of the personality factors investigated. Response specificity, particularly facial expressiveness, supported the view that specific affects have unique patterns of reactivity. The consistency of the dimensional relationships between evaluative judgments (i.e., pleasure and arousal) and physiological response, however, emphasizes that emotion is fundamentally organized by these motivational parameters.     

Respiratory resistance during emotional stimulation: evidence for a nonspecific effect of experienced arousal?

We investigated the effects of phasic emotional stimuli on total respiratory resistance (TRR) in 16 nonasthmatic students. Six series of happy, neutral, and depressing affective pictures and self-referent Velten statements were presented. Each stimulus was presented for 12 s and subsequently imagined for 12 s. TRR was measured by forced oscillations throughout the stimulus series, together with ventilation, cardiac activity (including respiratory sinus arrhythmia), and facial EMGs (corrugator supercilii, orbicularis oculi, and masseter). In addition, self-reports of mood, pleasure and arousal were obtained. TRR was increased during happy and depressing stimuli compared to neutral stimuli, with stronger effects for the inspiratory component of TRR. Ventilatory parameters did not explain the changes observed in TRR. Discrimination of affective categories by facial EMG was weak. Although EMG masseter activity did not account for this result, an influence of the respiration measurement procedure on facial EMG cannot be ruled out. The TRR results are in accordance with clinical reports of asthmatic symptom aggravation due to positive or negative emotional arousal.     

Facial reactions, autonomic activity and experienced emotion: a three component model of emotional conditioning

The present study was designed to evaluate whether aversively conditioned responses to facial stimuli are detectable in all three components of the emotional response system, i.e. the expressive/behavioral, the physiological/autonomic and the cognitive/experienced component of emotion. Two groups of subjects were conditioned to angry or happy facial expression stimuli using a 100 dB noise as UCS in a differential aversive conditioning paradigm. The three components of the emotional response system were measured as: Facial-EMG reactions (corrugator and zygomatic muscle regions); autonomic activity (skin conductance, SCR; SCR half recovery time, T/2; heart rate, HR); and ratings of experienced emotion. It was found that responses in all components of the emotional response system were detectable in the angry group as greater EMG and autonomic resistance to extinction and greater self-reported fear. More specifically the angry group showed a resistant conditioning effect for the facial-EMG corrugator muscle that was accompanied by resistant conditioning for SCR frequency, slower SCR recovery, resistant conditioning in HR and a higher self-reported fear than the happy group. Thus, aversive conditioning to angry facial stimuli induce a uniform negative emotional response pattern as indicated by all three components of the emotional response system. These data suggest that a negative 'affect program' triggers responses in the different emotional components. The results suggest that human subjects are biologically prepared to react with a negative emotion to angry facial stimuli.     

The effects of valence and arousal on the neural activity leading to subsequent memory

This study examined how valence and arousal affect the processes linked to subsequent memory for emotional information. While undergoing an fMRI scan, participants viewed neutral pictures and emotional pictures varying by valence and arousal. After the scan, participants performed a recognition test. Subsequent memory for negative or high arousal information was associated with occipital and temporal activity, whereas memory for positive or low arousal information was associated with frontal activity. Regression analyses confirmed that for negative or high arousal items, temporal lobe activity was the strongest predictor of later memory whereas for positive or low arousal items, frontal activity corresponded most strongly with later memory. These results suggest that the types of encoding processes relating to memory (e.g., sensory vs. elaborative processing) can differ based on the affective qualities of emotional information.     

Psychophysiological response patterns to positive and negative film stimuli

The aim of the present study was to investigate differential emotional response patterns to film stimuli by multimodal assessment of mood ratings, perception of bodily sensations, salivary cortisol, autonomic variables and facial electromyogram (EMG). Film stimuli, chosen to elicit positive and negative emotional states, were presented to 12 subjects with general anxiety disorder and 12 controls. Changes in mood, bodily sensations, autonomic activity (heart rate, respiration rate and skin conductance), facial EMG activity (corrugator and zygomatic muscle region) and salivary cortisol were measured. Analyses revealed differential changes in all response systems except for respiration rate and salivary cortisol. Although high-anxious subjects did not differ from controls in their average responses to the negative film stimuli, there is a tendency of a greater coherence of emotional response components in generalized anxiety subjects. However, spontaneous facial expressions to positive and negative film stimuli were associated with augmented electrodermal activity within both groups. Results are interpreted in light of directional response fractionation, dimensional approaches of emotion, and the facial feedback literature.     

Facial Reactions to Facial Expressions

Previous research has demonstrated that different patterns of facial muscle activity are correlated with different emotional states. In the present study subjects were exposed to pictures of happy and angry facial expressions, in response to which their facial electromyographic (EMG) activities, heart rate (HR), and palmar skin conductance responses (SCRs) were recorded. It was found that happy and angry faces evoked different facial EMG response patterns, with increased zygomatic region activity to happy stimuli and increased corrugator region activity to angry stimuli. Furthermore, both happy and angry faces evoked HR decelerations and similar SCR magnitudes. The results are interpreted as suggesting that facial EMG recordings provide a method for distinguishing between response patterns to “positive” and “negative” emotional visual stimuli.     

IAPS includes photographs that elicit low-arousal physiological responses in healthy volunteers

This article describes pleasant IAPS pictures that elicit low-arousal rather than the high-arousal physiological responses previously reported in the literature. Thirty-two International Affective Picture System (IAPS) photographs were grouped into 4 sets of 8 photographs: highly pleasant-arousing (sexual content and adventures), highly pleasant-relaxing pictures (landscapes, flowers or babies), neutral on both valence/arousal, and highly unpleasant-arousing ones. These stimuli were shown to 24 healthy Brazilian University students (12 males) who had their physiological responses recorded [corrugator and zygomatic facial electromyography activity, skin conductance, heart rate, and peripheral temperature]. Zygomatic EMG differentiated low-arousal pleasant photographs from high-arousal pleasant stimuli of the same valence.     

The psychophysiology of disgust: Differentiating negative emotional contexts with facial EMG

The goals of this study were (a) to examine differing views on the relationship between self-report of emotion and physiological expression of emotion, (b) to differentiate between negative emotional contexts during imagery using facial electromyogram (EMG), and (c) to describe the facial muscle patterning and autonomic physiology of situations that involve expelling or avoiding disgusting sensory stimulation. Fifty subjects imagined situations eliciting disgust, anger, pleasure, and joy in 8-s trials using a tone-cued imagery procedure. Heart rate, skin conductance level, and facial EMG at the corrugator, zygomatic, and levator labii superioris/alesque muscle regions were recorded during imagery, and self-reports of emotion were collected after imagery trials. Self-reports of emotion produced results consistent with the affective categorization of the images. Activity at the levator labii region was higher during disgust than during anger imagery. Corrugator region increase characterized the negative as compared with the positive emotional contents, and activity at the zygomatic region was higher during joy imagery than during the other three emotions. Heart rate acceleration was greater during disgust, anger, and joy imagery than during pleasant imagery. Disgust imagery could be discriminated from anger imagery using facial EMG, and the expressive physiology of disgust was occasioned by the action set of active avoidance or rejection of sensory stimulation.     

The specificity of infant emotional expression for emotion perception.

Attachment theory emphasizes the role of negative emotional expression in infancy for establishing proximity to and care of the caregiver. According to Lang's biphasic model of emotions protective reflexes (e.g. startle response) are primed if a defensive motivational set is activated. The aim of the study was to examine whether the perception of an infant emotional expression can prime such defensive behavior. The sample consisted of 48 university students. Startle reflex, corrugator and zygomatic EMG activity and subjective ratings of valence and arousal were assessed as a response to presentation of pictures of different emotional valence. Affective startle modulation was obtained when probes were presented during pictures of the International Affective Pictures System replicating previous findings. By contrast, negative infant emotion pictures did not prompt an augmentation of the startle response, although both the subjective ratings and the mimic EMG activity indicated a clear differentiation between negative and positive infant pictures. This pattern of findings was found only in a between-subject design, but not when the two picture sets were presented in the same session, indicating an interference of contrasting content of pictures.     

Individual differences in cognitive reappraisal: experiential and physiological responses to an anger provocation.

Effective emotion regulation is widely seen as vital for healthy adaptation. There remains considerable uncertainty, however, as to what constitutes effective emotion regulation. One promising emotion regulation strategy is cognitive reappraisal, which involves reframing emotional events so as to decrease their emotional impact. This strategy is useful because it seems to enable individuals to down-regulate negative feelings without the physiological costs that are associated with other forms of emotion regulation. It remains unknown, however, whether individual differences in the use of reappraisal are associated with experiential and physiological responses to anger-inducing situations. To examine this question, individuals either high or low in reappraisal were made angry in the laboratory while emotion experience and cardiovascular responses were assessed. Results indicated that compared to low reappraisers, high reappraisers had a more adaptive profile of emotion experience and cardiovascular responding. Specifically, across baseline and provocation periods, high reappraisers reported less anger, less negative emotion, and more positive emotion, showed greater cardiac output and ventricular contractility, and lesser total peripheral resistance. These findings suggest that reappraisers are successful at down-regulating negative emotions, even in the context of a potent negative emotion such as anger.     

Lateralized Facial Muscle Response to Positive and Negative Emotional Stimuli

Facial electromyography (EMG) was recorded from left and right zygomatic and corrugator muscle regions in response to reflective questions and during voluntary facial expressions. Both muscle regions showed consistent responses to five emotions (happiness, excitement, neutral, sadness, and fear) evoked in the involuntary condition (i.e. reflective questions) and four emotional facial expressions (happiness, excitement, sadness, and fear) self-generated in the voluntary condition. Lateralized responses were found for the zygomatic muscle in the involuntary condition: positive emotion questions elicited relatively greater right muscle activity than left muscle activity, while negative emotion questions elicited relatively greater left muscle activity than right muscle activity. Lateralized responses were found for the corrugator muscle in the voluntary condition, but were not significantly related to type of emotional expression. Sex differences indicating greater lateralization for females were found in some of the measures. The results are consistent with the hypothesized specialization of the left and right cerebral hemispheres for the mediation of positive and negative emotions, respectively.     

Prolonged marital stress is associated with short‐lived responses to positive stimuli

Marital stress is associated with a higher incidence of psychiatric disorders, in particular major depression. One pathway through which marital stress may impact emotional health is by compromising emotion‐responding processes. We examined a longitudinal sample of adults (N = 116; 59 males; 39–84 years) to verify how marital stress predicts reactivity to, and recovery from, emotional provocation. Individuals watched positive, neutral, and negative pictures while an objective measure of affective state, corrugator supercilii muscle activity, was recorded continuously. Our results indicate that marital stress is associated with short‐lived responses to positive pictures, indexed by a less persistent decrease in corrugator activity after picture offset. Extending beyond the prior focus on negative emotional processes, these results suggest that social stress may impact health by influencing the time course of responding to positive events.     

The influence of facial expression at perceptual threshold on electrodermal activity and social comfort distance

Interpersonal distance, an essential component of social interaction, is modulated by the emotion conveyed by others and associated physiological response. However, in modern societies with overcrowded and hyperstimulating environments, we can only surreptitiously glimpse the faces of others in order to quickly make behavioral adjustments. How this impacts social interactions is not yet well understood. In the present study, we investigated this issue by testing whether facial expressions that are difficult to identify modify the physiological response (Electrodermal Activity, EDA) and subsequent judgment of interpersonal comfort distance. We recorded participants’ EDA while they provided comfort judgments to interpersonal distances with a Point-Light Walker (PLW). The PLW, with an emotionally neutral gait, moved toward and crossed participants at various distances after the latter were exposed to a negative (anger), positive (happiness) or neutral facial expression presented at the perceptual threshold. Bayesian analyses of the data revealed an increase versus decrease of interpersonal comfort distance with the PLW depending on the negative versus positive emotional valence of the facial expression. They also showed an increase in EDA when the approaching PLW violated interpersonal comfort distance after participants were exposed to an angry facial expression. These effects correlated with the subjective assessment of the arousal of facial expressions. Thus, previous exposure to barely visible facial expressions can alter the representation of social comfort space and the physiological response associated with a violation of interpersonal comfort distances, depending on the valence and arousal of the emotional social stimuli.     

Looking at facial expressions: dysphoria and facial EMG

Previous research on interpersonal deficits among dysphoric individuals has been equivocal, with some studies finding that dysphoric persons show an increase in negative behavior and other studies finding no group differences. Most studies in this area have employed self-report instruments and behavioral coding systems to examine interpersonal displays. Using a different approach, we examined facial electromyography (EMG) reactivity to pictures of happy and unhappy expressions among dysphoric persons. Dysphoric and non-dysphoric persons viewed happy and unhappy facial expressions while zygomatic EMG and corrugator EMG activity was recorded. Results indicated that both groups showed the appropriate increase in corrugator EMG to unhappy expressions; however, dysphoric persons did not show the expected increase in zygomatic EMG activity to happy expressions while the control participants did show this response. Unexpectedly, the dysphoric group displayed an increase in corrugator EMG activity (e.g. frown response) to the happy facial expressions. These findings indicate that dysphoric persons have impaired interpersonal reactivity that is specific to happy facial displays.