Research

Facial EMG has been widely studied to assess its utility as a tool for measuring emotional reaction. A large number of these experiments have been conducted in controlled laboratory environments using a range of stimuli e.g., still pictures, movie clips and music pieces. More recently, market researchers have also been using facial EMG to test audience response to commercial advertising.

We have compiled a compendium of the abstracts to what we believe are the most relevant and important published studies on facial EMG. Where available we have provided the links to the full articles and indicated whether access to the articles is free or restricted. We hope the abstracts will give you a good sense of the content of the articles so you can decide if you would like to review an article in full.

Research Papers & Abstracts

1. Engagement, Emotions, and the Power of Radio - A New Study of How Radio Affects Consumer Emotions
   Conducted by Gallup and Robinson (Part One), Part of the Ongoing Series, "Radio and the Consumer's Mind: How Radio Works," published by the Radio Effectiveness Lab, June 2007
   This new Radio Ad Effectiveness Lab (Radio Ad Lab) study, conducted by Gallup and Robinson, was designed to assess how well radio ads can generate emotional responses and engage with consumers, compared to television ads. and it did so using advanced physiological methods that measure emotional responses in ways that don't require verbal responses. After evaluating 16 different real ad campaigns within actual programming, one conclusion is clear: Radio ads have emotional impact on consumers that is equal to that of television ads. The 16 radio campaigns in this study generated emotional levels just as high as their TV counterparts on average. And at the individual level, there were four radio campaigns showing significantly higher emotional impact than their TV counterparts, compared to only one higher-level TV spot.
    

2. More Than Mere Mimicry? The Influence of Emotion on Rapid Facial Reactions to Faces
   Moody, McIntosh, D.N., Mann, L.J., and Weisser, K.R., Emotion Vol. 7(2) (May 2007)
   Within a second of seeing an emotional facial expression, people typically match that expression. These rapid facial reactions (RFRs) often termed mimicry, are implicated in emotional contagion, social perception, and embodied affect, yet ambiguity remains regarding the mechanism(s) involved. Two studies evaluated whether RFRs  to faces are solely nonaffective motor responses or whether emotional processes are involved. Brow (corrugator, related to anger) and forehead (frontalis, related to fear) activity were recorded using facial electromyography (EMG) while undergraduates in two conditions (fear induction vs. neutral) viewed fear, anger, and neutral facial expressions. As predicted, fear induction increased fear expressions to angry faces within 1000 ms of exposure, demonstrating an emotional component of RFRs. This did not merely reflect increased fear from the induction, because responses to neutral faces were unaffected. Considering RFRs to be merely nonaffective automatic reactions is inaccurate. RFRs are not purely motor mimicry; emotion influences early facial responses to faces. The relevance of these data to emotional contagion, autism, and the mirror system-based perspectives on imitation is discussed.
      

3. Similar facial electromyographic responses to faces, voices and body expressions.
   Magnée, Maurice J. C. M., Stekelenburg, J.J., Kemner, C., de Gelder, Beatrice , Neuroreport Vol. 18(4) (Mar 2007)
   Observing facial expressions automatically prompts imitation, as can be seen with facial electromyography. To investigate whether this reaction is driven by automatic mimicry or by recognition of the emotion displayed the experimenters recorded electromyograph responses to presentations of facial expressions, face-voice combinations and bodily expressions, which resulted from happy and fearful stimuli. They observed emotion-specific facial muscle activity (zygomaticus for happiness, corrugator for fear) for all three stimulus categories. Results indicated that spontaneous facial expression was more akin to an emotional reaction than to facial mimicry and imitation of the seen face stimulus. The authors conclude that seeing a facial expression, an emotional body expression or hearing an emotional tone of voice all activate the affect program corresponding to the emotion displayed.
    

4. Measuring Emotional Valence to Understand the User's Experience of Software
   Hazlett, R.L., & Benedeck, J., International Journal of Human-Computer Studies Vol. 65 (2007)
   This paper reports on the results of two studies that used facial electromyography (EMG) measures combined with verbal and performance measures to provide feedback in the software design process on the user's emotional state. The first study assessed 16 participant's emotional responses while they passively viewed mock ups of proposed new operating system features. The second study measured the emotional responses of 15 participants while they actively used one of two versions of a media player. This multimodal assessment method was able to provide a sensitive measure of the desirability of the proposed software features, and a measure of emotional tension and mental effort expended in the interactive tasks.
    

5. Similar Facial Electromyographic Responses to Faces, Voices, and Body Expressions
   Magnee, Maurice, Stekelenburg, Jeroen, Kemner, Chantal and De Gelder, Beatrice, Cognitive Neuroscience & Neuropsychology Neuroreport Vol. 18 (2007)
   Observing facial expressions automatically prompts imitation, as can be seen with facial electromyography. To investigate whether this reaction is driven by automatic mimicry or by recognition of the emotion displayed they recorded electromyograph responses to presentation of facial expressions, face-voice combinations and bodily expressions, which resulted from happy and fearful stimuli. They observed emotion-specific facial muscle activity (zygomaticus for happiness, corrugator for fear) for all three stimulus categories. This indicates that spontaneous facial expression is more akin to an emotional reaction than to facial mimicry and imitation of the seen face stimulus. We suggest that seeing a facial expression, an emotional body expression or hearing an emotional tone of voice all activate the affect program corresponding to the emotion displayed.
    

6. Electromyographic Responses to Static and Dynamic Avatar Emotional Facial Expressions
   Weyers, P., Helberger, A., Hefele, C., and Pauli, P., Psychophysiology Vol. 43 (2006)
   Facial muscular reactions to avatars' static (neutral, happy, angry) and dynamic (morphs developing from neutral to happy or angry) facial expressions, presented for 1 s each, were investigated in 48 participants. Dynamic expressions led to better recognition rates and higher intensity and realism ratings. Angry expressions were rated as more intense than happy expressions. EMG recordings indicated emotion-specific reactions to happy avatars as reflected in increased M. zygomaticus major and decreased M. corrugator supercilii tension, with stronger reactions to dynamic as compared to static expressions. Although rated as more intense, angry expressions elicited no significant M. corrugator supercilii activation. We conclude that facial reactions to angry and to happy facial expressions hold different functions in social interactions. Further research should vary dynamics in different ways and also include additional emotional expressions.
    

7. Computing Emotion Awareness through Facial Electromyography
   Broek , E. L., Schut, M. H., Westerink, J. H. D., Herk Jan van, and Tuinenbreijer, K., Computer Science (Human-Computer Interaction), 3979, 51-62 (2006)
   To improve human-computer interaction (HCI), computers need to recognize and respond properly to their users emotional state. This is a fundamental application of affective computing, which relates to, arises from, or deliberately influences emotion. As a first step to a system that recognizes emotions of individual users, this research focuses on how emotional experiences are expressed in six parameters (i.e., mean, absolute deviation, standard deviation, variance, skewness, and kurtosis) of physiological measurements of three electromyography signals: frontalis (EMG1), corrugator supercilii (EMG2), and zygomaticus major (EMG3). The 24 participants were asked to watch .lm scenes of 120 seconds, which they rated afterward. These ratings enabled us to distinguish four categories of emotions: negative, positive, mixed, and neutral. The skewness of the EMG2 and four parameters of EMG3, discriminate between the four emotion categories. This, despite the coarse time windows that were used. Moreover, rapid processing of the signals proved to be possible. This enables tailored HCI facilitated by an emotional awareness of systems.
     

8. Study of Posed Emotion in Facial EMG Asymmetry
   Zhou, R., Hu, S., Perceptual & Motor Skills, Vol. 102(2) (April 2006)
   37 subjects' facial electromyography 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 regions 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 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.
    

9. The Facial Pattern of Disgust, Appetence, Excited Joy and Relaxed Joy: An improved Facial EMG Study
   Wolf, K., Mass, R., Ingenbleek, T., Kiefer, F., Naber, D. & Wiedemann,K., Scandinavian Journal of Psychology Vol. 46 (2005)
   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.
    

10. The Review of Applications and Measurements in Facial Electromyography
    Huang, Cheng-Ning, Chen, Chun-Han, and Chung, Hung-Yuan, Journal of Medical & Biological Engineering Vol. 25(1), 15-20, (2005)
    This paper reviews the various applications related to facial EMG. The authors survey the facial EMG application or masticatory function evaluation, speech analysis and recognition, and emotional expression observation. In addition, we also introduce the measurement of facial EMG including the electrode selection, electrode position and noise reduction. Finally, the authors discuss strategies to further develop the facial EMG technique.
     

11. Suboptimal Exposure to Facial Expressions: When Viewing Video Messages from a Small Screen: Effects in Emotion, Attention and Memory
    Ravaja, N., Kallinen, K. and Saari, T., Journal of Experimental Psychology: Applied Vol. 10(2) (2004)
    The authors examined the effects of suboptimally presented facial expressions on emotional responses and memory among 39 young adults viewing video (business news) messages from a small screen. Facial electromyography (EMG) was used as  physiological measures of emotion. The authors demonstrate that it is possible to use facial electromyography (EMG) activity recorded over corrugator supercilii, zygomaticus major, and orbicularis oculi regions as a more implicit affective measure in priming studies. That is, increased activity at the zygomaticus major (cheek) and corrugator supercilii (brow) muscle regions has been associated with positive emotions and negative emotions, respectively. Results showed that happy facial primes prompted increased (a) pleasure ratings, (b) orbicularis oculi EMG activity, (c) perceived trustworthiness, and (d) recognition memory for video messages with a positive emotional tone.
     

12. Effects of Positive and Negative Affect on Electromyographic Activity over Zygomaticus Major and Corrugator Supercilii
    Larsen, J.T., Norris, C.J., and Cacioppo, J.T., Psychophysiology Vol. 40 (2003)
    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 5 68) were exposed to series of affective pictures, sounds, and words. Consistent with speculations based on known properties of the neurophysiology of the facial structure, 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.
      

13. Presence-Related Influences of a Small Talking Facial Image on Psychophysiological Measures of Emotion and Attention
    Ravaja, Niklas (2002) 
    The author examines the effects of a small talking facial image on (a) emotional responses as indexed by self-report and facial electromyography (EMG) and (b) attention and engagement as indexed by so-called respiratory sinus arrhythmia (RSA) when viewing/listening to financial news from a simulated pocket PC among 36 subjects. The results showed that a talking facial image was rated as more pleasant and arousing as compared to a static facial image, and elicited progressively increasing zygomatic EMG activity. In addition, a talking facial image was associated with a decrease in RSA, but only among individuals scoring high on dispositional behavioral activation system (BAS) sensitivity. It is suggested that a small talking facial image contributes to sustained attention and engagement particularly among high BAS scorers, given that it may increase the sense of presence.
     

14. The Effects of Message Valence and Listener Arousal on Attention, Memory and Facial Muscular Responses to Radio Advertisements.
    Boll, P.D., Lang, A. and Potter, R.F., Communication Research, Vol. 28 (2001)
    This study tested the validity of using facial electromyography (EMG) as a physiological measure of the valence of radio listeners' emotional responses to advertisements and explored the effects of message valence and listener arousal on attention and memory. A within-subjects experiment was conducted in which participants listened to ten 60-second radio advertisements that had been coded in a pretest as having either a positive or negative emotional tone. Facial EMG, heart rate and skin conductance data were collected during exposure to the advertisements. Following exposure, participants completed free recall and recognition memory tests. Results demonstrated the validity of using facial EMG to assess the valence of emotional response to media messages. Heart rate data suggest that negative messages receive more attention than positive ones. Furthermore, how arousing a message is appears to be a better predictor of memory than message valence.
     

15. Mind at Ease Puts a Smile on the Face: Psychophysiological Evidence That Processing Facilitation Elicits Positive Affect
    Winkielman, P. and Cacioppo, J.T., Journal of Personality & Social Psychology, Vol. 81, No. 6, 989-1000 (2001)
    The affect system, in its position to monitor organismicenvironmental transactions, may be sensitive to the internal dynamics of information processing. Hence, the authors predicted that facilitation of stimulus processing should elicit a brief, mild, positive affective response. In 2 studies, participants watched a series of neutral pictures while the processing ease was unobtrusively manipulated. Affective reactions were assessed with facial electromyography (EMG). In both studies, easy-to-process pictures elicited higher activity over the region of zygomaticus major, indicating positive affect. The EMG data were paralleled by self-reports of positive responses to the facilitated stimuli. The findings suggest a close link between processing dynamics and affect and may help understand several preference phenomena, including the mere-exposure effect. The findings also highlight a potential source of affective biases in social judgments.
    Basic evaluative processes have long been of interest to psychologists. Such processes are central for theorists interested in attitudes (Eagly & Chaiken, 1998; Petty & Wegener, 1998), emotion (Niedenthal & Kitayama, 1994; Zajonc, 1998), and judgment (Clore, Schwarz, & Conway, 1994; Forgas, 1995). Traditionally, research focused primarily on descriptive determinants of evaluations. For example, attitude researchers explore how people integrate positive and negative features of a stimulus into an evaluative judgment (Skowronski & Carlston, 1989;Tesser & Martin, 1996). Emotion researchers study how feelings are determined by beliefs in the form of appraisals and attributions (Ellsworth, 1991; Frijda, 1988; Weiner, 1985). Researchers interested in automaticity investigate how a quick analysis of rudimentary stimulus features may result in automatic evaluative responses and affective priming (e.g., Bargh, Chaiken, Raymond, & Hymes, 1996; Fazio, Sanbonmatsu, Powell, & Kardes, 1986; Greenwald & Banaji, 1995; Murphy & Zajonc, 1993; Winkielman, Zajonc, & Schwarz, 1997). In contrast to these approaches, we build on earlier work to examine whether evaluations are sensitive to the dynamic aspect of mental operations, such as the ease of stimulus processing. To support this proposal, we present data showing that facilitation of stimulus processing leads to physiological responses indicative of positive affect as well as self-reports of higher liking.