A facial electromyographic investigation of affective contrast

Affective contrast refers to the tendency for stimuli to be judged as less evocative when preceded by more evocative same-valence stimuli. The authors used facial electromyographic (EMG) activity over corrugator supercilii , which is inversely related to affective valence, to determine if context influences underlying affective reactions. In Experiment 1 , moderately pleasant pictures elicited less activity over corrugator supercilii when they were embedded among mildly pleasant, as opposed to extremely pleasant, pictures. In Experiment 2 , moderately pleasant pictures elicited less activity over corrugator supercilii when they were embedded among mildly valent (i.e., pleasant and unpleasant), as opposed to extremely valent, pictures; moderately unpleasant pictures elicited comparable EMG activity regardless of context. Results indicate that context can influence affective reactions underlying affective judgments of moderately pleasant stimuli.     

Effects of positive and negative affect on electromyographic activity over zygomaticus major and corrugator supercilii

Pleasant stimuli typically elicit greater electromyographic (EMG) activity over zygomaticus major and less activity over corrugator supercilii than do unpleasant stimuli. To provide a systematic comparison of these 2 measures, the authors examined the relative form and strength of affective influences on activity over zygomaticus major and corrugator supercilii. Self-reported positive and negative affective reactions and facial EMG were collected as women (n = 68) were exposed to series of affective pictures, sounds, and words. Consistent with speculations based on known properties of the neurophysiology of the facial musculature, results revealed a stronger linear effect of valence on activity over corrugator supercilii versus zygomaticus major. In addition, positive and negative affect ratings indicated that positive and negative affect have reciprocal effects on activity over corrugator supercilii, but not zygomaticus major.     

State anxiety and affective physiology: effects of sustained exposure to affective pictures

Effects of sustained exposure to emotional stimuli on affective reactions and their recovery were examined to determine whether increasing exposure to a specific emotional content (e.g., unpleasant) cumulatively affects physiological responses; and whether motivational activation persists following sustained exposure. Participants viewed pleasant, neutral, and unpleasant IAPS pictures, presented in blocks separated by an inter-block interval. With increasing exposure to unpleasant pictures, startle magnitude showed greater potentiation, and corrugator EMG activity increased. Both affective startle and corrugator modulation persisted following exposure to unpleasant pictures. The cumulative effects of sustained exposure to unpleasant pictures were enhanced for those reporting higher state anxiety, consistent with the hypothesis that sustained aversive exposure leads to increased defensive activation. These findings suggest sustained exposure to unpleasant pictures may induce a short-term mood state, and may be a useful paradigm to study individuals who vary in symptoms of anxiety.     

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.     

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.     

Preattentive processing of feared stimuli in blood-injection-injury fearful subjects

This research aimed to study the defence responses of blood-injection-injury (BII) fearful subjects elicited by the preattentive processing of their feared objects and by an abrupt acoustic stimulus. We selected 21 BII fearful subjects and 25 non-fearful controls from an initial sample of 128 women, according to their scores on the Fear Survey Scale (damage subscale) and the Mutilation Questionnaire. Subjects were exposed to a burst of white noise to promote a defence response, and to 48 pictures, depicting mutilations, as well as other affective contents, displayed through a backward masking procedure. Heart rate (HR), skin conductance response (SCR) and corrugator supercilii activity were continuously recorded throughout the task. Both groups showed similar SCRs, EMG activity and cardiac defence responses to the acoustic stimulus, though fearful subjects showed greater initial HR deceleration than controls. While BII fearful subjects displayed the usual defence response when exposed to a non-feared threatening stimulus, the preattentive processing of the pictures did not reveal autonomic differences between fearful subjects and controls. Mutilation pictures, however, evoked the greatest EMG activity, but only in the fearful group. These data further extend previous research on conscious perception of blood-related stimuli in BII fearful subjects, by showing a failure to recruit autonomic defence responses when blood-related pictures appear outside of conscious awareness.     

Expertise in video game playing is associated with reduced valence‐concordant emotional expressivity

In carefully selected groups of video game playing (VGP) experts and nonexperts, we examined valence‐concordant emotional expressivity. We measured electromyographic (EMG) activity over the corrugator supercilii muscle while participants viewed pleasant, neutral, and unpleasant pictures. Potential group differences concerning valence‐concordant expressivity may arise from differences concerning the participants' emotional reactivity. To control for such differences, we concomitantly measured skin conductance response (SCR) and, in a separate affect misattribution procedure (AMP), valence transfer from the same set of stimuli. Importantly, we found attenuated valence‐concordant EMG activity over the corrugator supercilii muscle in VGP experts compared to nonexperts, but no differences were evident concerning SCR or valence transfer in the AMP. The findings suggest that expertise in VGP is particularly associated with reduced valence‐concordant emotional expressivity.     

Physical activity does not disturb the measurement of startle and corrugator responses during affective picture viewing

Healthy college females (n=24) completed counterbalanced conditions of 20 min of very low and low intensity cycling exercise and seated rest. Startle and corrugator supercilii responses, and baseline orbicularis oculi and corrugator supercilii electromyographic (EMG) activity, were measured during each exercise condition while participants viewed pleasant, neutral and unpleasant pictures. The exercise conditions did not alter the magnitude of the startle or corrugator responses compared with the resting control condition. Baseline orbicularis EMG increased slightly and baseline corrugator EMG increased significantly, during the low intensity exercise condition. In conclusion, low intensity physical activity is not sufficient to alter emotional responsiveness as assessed by the acoustic startle eyeblink response and corrugator supercilii EMG responses during the viewing of pleasant, neutral, and unpleasant pictures. Despite modestly increased baseline EMG levels, reliable startle and corrugator EMG responses can be obtained in healthy college females during picture viewing while performing low intensity cycling exercise.     

What do I do now? Intolerance of uncertainty is associated with discrete patterns of anticipatory physiological responding to different contexts

Heightened physiological responses to uncertainty are a common hallmark of anxiety disorders. Many separate studies have examined the relationship between individual differences in intolerance of uncertainty (IU) and physiological responses to uncertainty during different contexts. Despite this, there is a scarcity of research examining the extent to which individual differences in IU are related to shared or discrete patterns of anticipatory physiological responding across different contexts. Anticipatory physiological responses to uncertainty were assessed in three different contexts (associative threat learning and extinction, threat uncertainty, decision‐making) within the same sample (n = 45). During these tasks, behavioral responses (i.e., reaction times, choices), skin conductance, and corrugator supercilli activity were recorded. In addition, self‐reported IU and trait anxiety were measured. IU was related to both skin conductance and corrugator supercilii activity for the associative threat learning and extinction context and decision‐making context. However, trait anxiety was related to corrugator supercilii activity during the threat uncertainty context. Ultimately, this research helps us to further tease apart the role of IU on different aspects of anticipation (i.e., valence and arousal) across contexts, which will be relevant for future IU‐related models of psychopathology.     

Emotional reactions in children: verbal, physiological, and behavioral responses to affective pictures

Many studies have shown a consistent pattern in adults' responses to affective pictures and there is growing evidence of gender differences, as well. Little is known, though, about children's verbal, behavioral, and physiological responses to affective pictures. Two experiments investigated children's responses to pictures. In Experiment 1, children, adolescents, and adults viewed pictures varying in affective content and rated them for pleasure, arousal, and dominance. Results indicated that children and adolescents rated the pictures similarly to adults. In Experiment 2, physiological responses, self-report, and viewing time were measured while children viewed affective pictures. As with adults, children's responses reflected the affective content of the pictures. Gender differences in affective evaluations, corrugator activity, skin conductance, startle modulation, and viewing time indicated that girls were generally more reactive to unpleasant materials.     

Picture media and emotion: Effects of a sustained affective context

Pleasant, neutral, or unpleasant pictures were presented in a continuous series, and the effects of repetitive exposure to pictures of the same affective valence were assessed in somatic (corrugator electromyographic [EMG] activity) and visceral (heart rate and skin conductance) systems. Probe stimuli (startle or reaction time probes) were presented to index emotional and attentional concomitants of processing. Affective discrimination was maintained across time in all response systems, and sensitization was found for the corrugator EMG response. Responses to reaction time probes indexed differences in attentional allocation as a function of cognitive and affective variables in this paradigm. Taken together, the data suggest that presentation of a series of affective pictures of similar valence produces emotional reactions that are either maintained or sensitized across the temporal intervals used here but that do not habituate.     

Positive emotional reactions to loved names

Studies concerning personal attachment have successfully used loved familiar faces to prompt positive affective and physiological reactions. Moreover, the processing of emotional words shows similar physiological patterns to those found with affective pictures. The objective of this study was to assess whether the passive viewing of loved names would produce a pattern of subjective and physiological reactivity similar to that produced by the passive viewing of loved faces. The results showed that, compared to neutral (unknown) and famous names, loved names produced a biphasic pattern of heart rate deceleration‐acceleration, heightened skin conductance and zygomaticus muscle activity, inhibition of corrugator muscle activity, and potentiation of the startle reflex response. This pattern of physiological responses was accompanied by subjective reports of higher positive affect and arousal for loved names than for neutral and famous ones. These findings highlight not only the similarity but also the differences between the affective processing of identity recognition by loved faces and names.     

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.     

Error‐related electromyographic activity over the corrugator supercilii is associated with neural performance monitoring

Emerging research in social and affective neuroscience has implicated a role for affect and motivation in performance monitoring and cognitive control. No study, however, has investigated whether facial electromyography (EMG) over the corrugator supercilii—a measure associated with negative affect and the exertion of effort—is related to neural performance monitoring. Here, we explored these potential relationships by simultaneously measuring the error‐related negativity, error positivity (Pe), and facial EMG over the corrugator supercilii muscle during a punished, inhibitory control task. We found evidence for increased facial EMG activity over the corrugator immediately following error responses, and this activity was related to the Pe for both between‐ and within‐subject analyses. These results are consistent with the idea that early, avoidance‐motivated processes are associated with performance monitoring, and that such processes may also be related to orienting toward errors, the emergence of error awareness, or both.     

The effect of cognitive reappraisal on physiological reactivity and emotional memory

We investigated the effect of cognitive reappraisal on emotional arousal, facial expressivity and subsequent memory. Men and women viewed emotionally negative pictures while they attempted to either increase or decrease negative emotions elicited by the pictures, or to simply view the pictures. Neutral pictures were also presented with instructions to simply view the pictures. Concurrent changes in emotional arousal and valence were assessed with skin conductance responses (SCRs) and facial corrugator electromyographic responses (EMG), respectively. Picture memory was assessed with an immediate recall test and a delayed recognition test. Relative to simply viewing pictures, voluntary reappraisal to increase negative emotion generated greater facial corrugator EMG and SCR responses, and reappraisal to decrease negative emotion generated decreased corrugator EMG responses. Men showed enhanced recognition for pictures presented during the increase and decrease conditions, whereas women showed comparable recognition performance across all regulation conditions. The modulation of subsequent recognition memory associated with decreasing emotion was inversely associated with changes in physiological responses. Our results suggest that sex is an important factor to consider in determining how reappraisal-induced physiological changes are associated with subsequent changes in memory. These findings contribute to our understanding of how reappraising emotion exerts both immediate and enduring influences on physiological responses and subsequent memory.     

Reactions to facial expressions: effects of social context and speech anxiety on responses to neutral, anger, and joy expressions

Male and female participants (n=19) high or low in speech fear viewed pictures of faces posed in anger, neutral, and joyful expressions for 8s each. Zygomaticus major and corrugator supercilii EMG, skin conductance, and heart rate were measured during picture viewing, and subjective ratings were made after each picture. Compared to anger expressions, joy expressions were responded to with greater zygomatic EMG, less corrugator EMG, and greater heart rate and skin conductance. Physiological response to neutral expressions was similar to response to anger expressions. Expressions posed by women were responded to physiologically more negatively than expressions posed by men. More fearful participants exhibited more negative and less positive facial expressions, and skin conductance responses suggesting greater attention when viewing negative expressions. Results suggest that reactions to facial expressions are influenced by social context, and are not simple mimicry.     

Affective reactions to briefly presented pictures

Affective reactions to briefly presented pictures were investigated to determine whether fleeting stimuli engage the motivational systems mediating emotional responses. Emotional and neutral pictures were presented for 500 ms; heart rate, skin conductance, corrugator EMG, and the evoked startle reflex were measured. The time course of reflex modulation was similar to that obtained with longer (6 s) presentations, suggesting that picture processing continues in the absence of a sensory stimulus. Affective reactions found with more sustained presentation were also obtained, with more corrugator EMG activity for unpleasant pictures, and greater skin conductance reactivity for emotional pictures. Heart rate modulation, however, appears to rely on the presence of a sensory stimulus. The data also suggest that brief presentations of unpleasant pictures may result in less defensive activation than sustained presentation.     

Emotional response in patients with frontal brain damage: effects of affective valence and information content

The authors investigated the role of the frontal lobes in the emotional response in 19 patients with brain damage and 23 control subjects. They studied the modulation of the startle blink reflex by affective pictures, and other autonomic responses. Patients showed a dissociation between the startle reflex and the affective valence ratings of the pictures, as a result of a low inhibition of the startle reflex by pleasant pictures. Pictures elicited lower skin conductance responses (SCRs) in patients than in controls, whereas the groups did not differ in the SCRs prompted by less significant acoustic stimuli. The findings point to the frontal lobe as a structure involved in the emotional response and in the physiological emotional arousal related to the complexity of the stimuli.     

Manipulating affective state using extended picture presentations

Separate, extended series of positive, negative, and neutral pictures were presented to 24 (12 men, 12 women) undergraduates. Each series was presented on a different day, with full counterbalancing of presentation orders. Affective state was measured using (a) orbicularis oculi activity in response to acoustic startle probes during picture' presentation, (b) corrugator supercilii activity between and during picture presentation, and (c) changes in self-reports of positive and negative affect. Participants exhibited larger eyeblink reflex magnitudes when viewing negative than when viewing positive pictures. Corrugator activity was also greater during the negative than during the positive picture set, during both picture presentation and the period between pictures. Self-reports of negative affect increased in response to the negative picture set. and self-reports of positive affect were greatest following the positive picture set. These findings suggest that extended picture presentation is an effective method of manipulating affective state and further highlight the utility of startle probe and facial electromyographic measures in providing on-line readouts of affective state.     

Probe P3 and blinks: Two measures of affective startle modulation

Two concurrent measures of the evoked startlé response, the elicited blink reflex and the event-related potential, were measured while individuals viewed pictures that varied in pleasure and arousal. Replicating previous findings, the blink response was modulated by picture pleasantness, with larger reflexes elicited in the context of viewing unpleasant versus pleasant pictures. However, the probe P3 was primarily modulated by picture arousal, with smaller P3 responses elicited when viewing affective (pleasant or unpleasant) than when viewing neutral pictures. Both modulatory effects were sustained for probes presented in a subsequent picture imagery period. These data suggest that two measurable responses to the same startle probe are differentially modified by emotional context, with blink magnitude varying with pleasure and probe P3 varying with stimulus arousal.