The Odor Context Facilitates the Perception of Low-Intensity Facial Expressions of Emotion

It has been established that the recognition of facial expressions integrates contextual information. In this study, we aimed to clarify the influence of contextual odors. The participants were asked to match a target face varying in expression intensity with non-ambiguous expressive faces. Intensity variations in the target faces were designed by morphing expressive faces with neutral faces. In addition, the influence of verbal information was assessed by providing half the participants with the emotion names. Odor cues were manipulated by placing participants in a pleasant (strawberry), aversive (butyric acid), or no-odor control context. The results showed two main effects of the odor context. First, the minimum amount of visual information required to perceive an expression was lowered when the odor context was emotionally congruent: happiness was correctly perceived at lower intensities in the faces displayed in the pleasant odor context, and the same phenomenon occurred for disgust and anger in the aversive odor context. Second, the odor context influenced the false perception of expressions that were not used in target faces, with distinct patterns according to the presence of emotion names. When emotion names were provided, the aversive odor context decreased intrusions for disgust ambiguous faces but increased them for anger. When the emotion names were not provided, this effect did not occur and the pleasant odor context elicited an overall increase in intrusions for negative expressions. We conclude that olfaction plays a role in the way facial expressions are perceived in interaction with other contextual influences such as verbal information.     

Unconsciously Triggered Emotional Conflict by Emotional Facial Expressions

The present study investigated whether emotional conflict and emotional conflict adaptation could be triggered by unconscious emotional information as assessed in a backward-masked affective priming task. Participants were instructed to identify the valence of a face (e.g., happy or sad) preceded by a masked happy or sad face. The results of two experiments revealed the emotional conflict effect but no emotional conflict adaptation effect. This demonstrates that emotional conflict can be triggered by unconsciously presented emotional information, but participants may not adjust their subsequent performance trial-by trial to reduce this conflict.     

Self-Relevance Appraisal Influences Facial Reactions to Emotional Body Expressions

People display facial reactions when exposed to others'' emotional expressions, but exactly what mechanism mediates these facial reactions remains a debated issue. In this study, we manipulated two critical perceptual features that contribute to determining the significance of others'' emotional expressions: the direction of attention (toward or away from the observer) and the intensity of the emotional display. Electromyographic activity over the corrugator muscle was recorded while participants observed videos of neutral to angry body expressions. Self-directed bodies induced greater corrugator activity than other-directed bodies; additionally corrugator activity was only influenced by the intensity of anger expresssed by self-directed bodies. These data support the hypothesis that rapid facial reactions are the outcome of self-relevant emotional processing.     

Time Perception and Dynamics of Facial Expressions of Emotions

Two experiments were run to examine the effects of dynamic displays of facial expressions of emotions on time judgments. The participants were given a temporal bisection task with emotional facial expressions presented in a dynamic or a static display. Two emotional facial expressions and a neutral expression were tested and compared. Each of the emotional expressions had the same affective valence (unpleasant), but one was high-arousing (expressing anger) and the other low-arousing (expressing sadness). Our results showed that time judgments are highly sensitive to movements in facial expressions and the emotions expressed. Indeed, longer perceived durations were found in response to the dynamic faces and the high-arousing emotional expressions compared to the static faces and low-arousing expressions. In addition, the facial movements amplified the effect of emotions on time perception. Dynamic facial expressions are thus interesting tools for examining variations in temporal judgments in different social contexts.     

New Tests to Measure Individual Differences in Matching and Labelling Facial Expressions of Emotion,and Their Association with Ability to Recognise Vocal Emotions and Facial Identity

Although good tests are available for diagnosing clinical impairments in face expression processing, there is a lack of strong tests for assessing “individual differences” – that is, differences in ability between individuals within the typical, nonclinical, range. Here, we develop two new tests, one for expression perception (an odd-man-out matching task in which participants select which one of three faces displays a different expression) and one additionally requiring explicit identification of the emotion (a labelling task in which participants select one of six verbal labels). We demonstrate validity (careful check of individual items, large inversion effects, independence from nonverbal IQ, convergent validity with a previous labelling task), reliability (Cronbach’s alphas of.77 and.76 respectively), and wide individual differences across the typical population. We then demonstrate the usefulness of the tests by addressing theoretical questions regarding the structure of face processing, specifically the extent to which the following processes are common or distinct: (a) perceptual matching and explicit labelling of expression (modest correlation between matching and labelling supported partial independence); (b) judgement of expressions from faces and voices (results argued labelling tasks tap into a multi-modal system, while matching tasks tap distinct perceptual processes); and (c) expression and identity processing (results argued for a common first step of perceptual processing for expression and identity).     

Tuning to the Positive: Age-Related Differences in Subjective Perception of Facial Emotion

Facial expressions aid social transactions and serve as socialization tools, with smiles signaling approval and reward, and angry faces signaling disapproval and punishment. The present study examined whether the subjective experience of positive vs. negative facial expressions differs between children and adults. Specifically, we examined age-related differences in biases toward happy and angry facial expressions. Young children (5–7 years) and young adults (18–29 years) rated the intensity of happy and angry expressions as well as levels of experienced arousal. Results showed that young children—but not young adults—rated happy facial expressions as both more intense and arousing than angry faces. This finding, which we replicated in two independent samples, was not due to differences in the ability to identify facial expressions, and suggests that children are more tuned to information in positive expressions. Together these studies provide evidence that children see unambiguous adult emotional expressions through rose-colored glasses, and suggest that what is emotionally relevant can shift with development.     

Sex Differences in the Rapid Detection of Emotional Facial Expressions

Background

Previous studies have shown that females and males differ in the processing of emotional facial expressions including the recognition of emotion, and that emotional facial expressions are detected more rapidly than are neutral expressions. However, whether the sexes differ in the rapid detection of emotional facial expressions remains unclear.

Methodology/Principal Findings

We measured reaction times (RTs) during a visual search task in which 44 females and 46 males detected normal facial expressions of anger and happiness or their anti-expressions within crowds of neutral expressions. Anti-expressions expressed neutral emotions with visual changes quantitatively comparable to normal expressions. We also obtained subjective emotional ratings in response to the facial expression stimuli. RT results showed that both females and males detected normal expressions more rapidly than anti-expressions and normal-angry expressions more rapidly than normal-happy expressions. However, females and males showed different patterns in their subjective ratings in response to the facial expressions. Furthermore, sex differences were found in the relationships between subjective ratings and RTs. High arousal was more strongly associated with rapid detection of facial expressions in females, whereas negatively valenced feelings were more clearly associated with the rapid detection of facial expressions in males.

Conclusion

Our data suggest that females and males differ in their subjective emotional reactions to facial expressions and in the emotional processes that modulate the detection of facial expressions.     

Relationships among Facial Mimicry,Emotional Experience,and Emotion Recognition

Background

The relationships between facial mimicry and subsequent psychological processes remain unclear. We hypothesized that the congruent facial muscle activity would elicit emotional experiences and that the experienced emotion would induce emotion recognition.

Methodology/Principal Findings

To test this hypothesis, we re-analyzed data collected in two previous studies. We recorded facial electromyography (EMG) from the corrugator supercilii and zygomatic major and obtained ratings on scales of valence and arousal for experienced emotions (Study 1) and for experienced and recognized emotions (Study 2) while participants viewed dynamic and static facial expressions of negative and positive emotions. Path analyses showed that the facial EMG activity consistently predicted the valence ratings for the emotions experienced in response to dynamic facial expressions. The experienced valence ratings in turn predicted the recognized valence ratings in Study 2.

Conclusion

These results suggest that facial mimicry influences the sharing and recognition of emotional valence in response to others'' dynamic facial expressions.     

Facial EMG Responses to Combat-Related Visual Stimuli in Veterans With and Without Posttraumatic Stress Disorder

Veterans with (n = 10) and without (n = 10) posttraumatic stress disorder (PTSD) participated in an exploratory study of facial reactivity to neutral slides and to slides depicting unpleasant combat-related material that were previously determined to be emotionally evocative. It was found that the zygomaticus major (cheek), masseter (jaw), and lateral frontalis (forehead) muscles were especially reactive to the combat slides in the veterans with PTSD, suggesting the importance of facial emotional expression in this disorder. The PTSD participants' self-reports of overall distress paralleled these effects. However, autonomic reactivity did not reflect general arousal effects due to the visual stimuli, showing both the sensitivity of facial muscle assessment in this context and the need for further research on the relationship between stimulus modality and physiological trauma reactions. Additional directions for research in this area are discussed including efforts to correlate subjective and physiological reactions.     

The Power of an Infant's Smile: Maternal Physiological Responses to Infant Emotional Expressions

Infant emotional expressions, such as distress cries, evoke maternal physiological reactions. Most of which involve accelerated sympathetic nervous activity. Comparatively little is known about effects of positive infant expressions, such as happy smiles, on maternal physiological responses. This study investigated how physiological and psychological maternal states change in response to infants’ emotional expressions. Thirty first-time mothers viewed films of their own 6- to 7-month-old infants’ affective behavior. Each observed a video of a distress cry followed by a video showing one of two expressions (randomly assigned): a happy smiling face (smile condition) or a calm neutral face (neutral condition). Both before and after the session, participants completed a self-report inventory assessing their emotional states. The results of the self-report inventory revealed no effects of exposure to the infant videos. However, the mothers in the smile condition, but not in the neutral condition, showed deceleration of skin conductance. These findings demonstrate that the mothers who observed their infants smiling showed decreased sympathetic activity. We propose that an infant’s positive emotional expression may affect the branch of the maternal stress-response system that modulates the homeostatic balance of the sympathetic and parasympathetic nervous systems.     

Dynamic Facial Expressions of Emotion Transmit an Evolving Hierarchy of Signals over Time

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The Influence of a Working Memory Task on Affective Perception of Facial Expressions

In a dual-task paradigm, participants performed a spatial location working memory task and a forced two-choice perceptual decision task (neutral vs. fearful) with gradually morphed emotional faces (neutral ∼ fearful). Task-irrelevant word distractors (negative, neutral, and control) were experimentally manipulated during spatial working memory encoding. We hypothesized that, if affective perception is influenced by concurrent cognitive load using a working memory task, task-irrelevant emotional distractors would bias subsequent perceptual decision-making on ambiguous facial expression. We found that when either neutral or negative emotional words were presented as task-irrelevant working-memory distractors, participants more frequently reported fearful face perception - but only at the higher emotional intensity levels of morphed faces. Also, the affective perception bias due to negative emotional distractors correlated with a decrease in working memory performance. Taken together, our findings suggest that concurrent working memory load by task-irrelevant distractors has an impact on affective perception of facial expressions.     

The Rewarding Aspects of Music Listening Are Related to Degree of Emotional Arousal

Background

Listening to music is amongst the most rewarding experiences for humans. Music has no functional resemblance to other rewarding stimuli, and has no demonstrated biological value, yet individuals continue listening to music for pleasure. It has been suggested that the pleasurable aspects of music listening are related to a change in emotional arousal, although this link has not been directly investigated. In this study, using methods of high temporal sensitivity we investigated whether there is a systematic relationship between dynamic increases in pleasure states and physiological indicators of emotional arousal, including changes in heart rate, respiration, electrodermal activity, body temperature, and blood volume pulse.

Methodology

Twenty-six participants listened to self-selected intensely pleasurable music and “neutral” music that was individually selected for them based on low pleasure ratings they provided on other participants'' music. The “chills” phenomenon was used to index intensely pleasurable responses to music. During music listening, continuous real-time recordings of subjective pleasure states and simultaneous recordings of sympathetic nervous system activity, an objective measure of emotional arousal, were obtained.

Principal Findings

Results revealed a strong positive correlation between ratings of pleasure and emotional arousal. Importantly, a dissociation was revealed as individuals who did not experience pleasure also showed no significant increases in emotional arousal.

Conclusions/Significance

These results have broader implications by demonstrating that strongly felt emotions could be rewarding in themselves in the absence of a physically tangible reward or a specific functional goal.     

Women's Greater Ability to Perceive Happy Facial Emotion Automatically: Gender Differences in Affective Priming

There is evidence that women are better in recognizing their own and others' emotions. The female advantage in emotion recognition becomes even more apparent under conditions of rapid stimulus presentation. Affective priming paradigms have been developed to examine empirically whether facial emotion stimuli presented outside of conscious awareness color our impressions. It was observed that masked emotional facial expression has an affect congruent influence on subsequent judgments of neutral stimuli. The aim of the present study was to examine the effect of gender on affective priming based on negative and positive facial expression. In our priming experiment sad, happy, neutral, or no facial expression was briefly presented (for 33 ms) and masked by neutral faces which had to be evaluated. 81 young healthy volunteers (53 women) participated in the study. Subjects had no subjective awareness of emotional primes. Women did not differ from men with regard to age, education, intelligence, trait anxiety, or depressivity. In the whole sample, happy but not sad facial expression elicited valence congruent affective priming. Between-group analyses revealed that women manifested greater affective priming due to happy faces than men. Women seem to have a greater ability to perceive and respond to positive facial emotion at an automatic processing level compared to men. High perceptual sensitivity to minimal social-affective signals may contribute to women's advantage in understanding other persons' emotional states.     

The Insular Cortex: Relationship to Skin Conductance Responses to Facial Expression of Emotion in Temporal Lobe Epilepsy

The insula plays an important role both in emotion processing and in the generation of epileptic seizures. In the current study we examined thickness of insular cortices and bilateral skin conductance responses (SCR) in healthy subjects in addition to a small number of patients with temporal lobe epilepsy. SCR measures arousal and is used to assess non-conscious responses to emotional stimuli. We used two emotion tasks, one explicitly about emotion and the other implicit. The explicit task required judgments about emotions being expressed in photographs of faces, while the implicit one required judgments about the age of the people in the photographs. Patients and healthy differed in labeling neutral faces, but not other emotions. They also differed in their SCR to emotions, though the profile depended on which hand the recordings were from. Finally, we found relationships between the thickness of the insula and SCR to each task: in the healthy group the thickness of the left insula was related to SCR to the emotion-labeling task; in the patient group it was between the thickness of the right insula and SCR in the age-labeling task. These patterns were evident only for the right hand recordings, thus underscoring the importance of bilateral recordings.     

Maternal Attachment Representation and Neurophysiological Processing during the Perception of Infants’ Emotional Expressions

The perception of infant emotions is an integral part of sensitive caregiving within the mother-child relationship, a maternal ability which develops in mothers during their own attachment history. In this study we address the association between maternal attachment representation and brain activity underlying the perception of infant emotions. Event related potentials (ERPs) of 32 primiparous mothers were assessed during a three stimulus oddball task presenting negative, positive and neutral emotion expressions of infants as target, deviant or standard stimuli. Attachment representation was assessed with the Adult Attachment Interview during pregnancy. Securely attached mothers recognized emotions of infants more accurately than insecurely attached mothers. ERPs yielded amplified N170 amplitudes for insecure mothers when focusing on negative infant emotions. Secure mothers showed enlarged P3 amplitudes to target emotion expressions of infants compared to insecure mothers, especially within conditions with frequent negative infant emotions. In these conditions, P3 latencies were prolonged in insecure mothers. In summary, maternal attachment representation was found associated with brain activity during the perception of infant emotions. This further clarifies psychological mechanisms contributing to maternal sensitivity.     

ANS Responses and Facial Expressions Differentiate between the Taste of Commercial Breakfast Drinks

The high failure rate of new market introductions, despite initial successful testing with traditional sensory and consumer tests, necessitates the development of other tests. This study explored the ability of selected physiological and behavioral measures of the autonomic nervous system (ANS) to distinguish between repeated exposures to foods from a single category (breakfast drinks) and with similar liking ratings. In this within-subject study 19 healthy young adults sipped from five breakfast drinks, each presented five times, while ANS responses (heart rate, skin conductance response and skin temperature), facial expressions, liking, and intensities were recorded. The results showed that liking was associated with increased heart rate and skin temperature, and more neutral facial expressions. Intensity was associated with reduced heart rate and skin temperature, more neutral expressions and more negative expressions of sadness, anger and surprise. Strongest associations with liking were found after 1 second of tasting, whereas strongest associations with intensity were found after 2 seconds of tasting. Future studies should verify the contribution of the additional information to the prediction of market success.     

Aspects of Facial Contrast Decrease with Age and Are Cues for Age Perception

Age is a primary social dimension. We behave differently toward people as a function of how old we perceive them to be. Age perception relies on cues that are correlated with age, such as wrinkles. Here we report that aspects of facial contrast–the contrast between facial features and the surrounding skin–decreased with age in a large sample of adult Caucasian females. These same aspects of facial contrast were also significantly correlated with the perceived age of the faces. Individual faces were perceived as younger when these aspects of facial contrast were artificially increased, but older when these aspects of facial contrast were artificially decreased. These findings show that facial contrast plays a role in age perception, and that faces with greater facial contrast look younger. Because facial contrast is increased by typical cosmetics use, we infer that cosmetics function in part by making the face appear younger.     

A Novel Method Testing the Ability to Imitate Composite Emotional Expressions Reveals an Association with Empathy

Social communication relies on intentional control of emotional expression. Its variability across cultures suggests important roles for imitation in developing control over enactment of subtly different facial expressions and therefore skills in emotional communication. Both empathy and the imitation of an emotionally communicative expression may rely on a capacity to share both the experience of an emotion and the intention or motor plan associated with its expression. Therefore, we predicted that facial imitation ability would correlate with empathic traits. We built arrays of visual stimuli by systematically blending three basic emotional expressions in controlled proportions. Raters then assessed accuracy of imitation by reconstructing the same arrays using photographs of participants’ attempts at imitations of the stimuli. Accuracy was measured as the mean proximity of the participant photographs to the target stimuli in the array. Levels of performance were high, and rating was highly reliable. More empathic participants, as measured by the empathy quotient (EQ), were better facial imitators and, in particular, performed better on the more complex, blended stimuli. This preliminary study offers a simple method for the measurement of facial imitation accuracy and supports the hypothesis that empathic functioning may utilise motor control mechanisms which are also used for emotional expression.