Do Unilateral Right and Left Face Contractions Induce Positive and Negative Emotions? A Further Test of Schiff and Lamon's (1989) Hypothesis

Schiff and Lamon (1989) proposed that unilateral face contractions induce positive or negative changes in emotion depending on the side of contraction; support for this proposal, however, has been mixed. In a new test, 40 right-handed and 38 left-handed men performed four alternating face contractions (LRLR or RLRL) and, after each one, completed a different version of the Depression Adjective Checklist (Lubin, 1994). A repeated-measures ANCOVA failed to reveal any significant effect of side of face contraction or handedness on direction of emotion change. Instead, regardless of side of contraction, the subjects' negative emotional state increased significantly across the four contractions with the degree of change being significantly related to the subjects' reported level of difficulty in holding the contraction irrespective of whether the more difficult side was the left or the right.     

Asymmetries of expressive facial movements during experimentally induced positive vs. negative mood states: A video-analytical study

Abstract

When reviewing the literature, it appears that the striking disparity among findings concerning facial expression asymmetry may be due to inconsistent experimental settings. In our study we applied a set of standard mood induction procedures within a semi-standardised face-to-face interview. We predicted a greater right-sided lifting of the corners of the mouth during positive mood states and a greater left-sided lowering during negative mood states. The results were in line with our expectations. Our interpretation attempts to reconcile the “right hemisphere hypothesis” and the “valence hypothesis” of emotional processing.     

Is manipulation of mood a critical component of cognitive bias modification procedures?

This paper investigates whether changes in mood state are an important component of cognitive bias modification (CBM) procedures. In a novel CBM procedure participants read either positive or negative statements relating to social issues for 5 min. Interpretation bias was measured by means of a scrambled sentence test, which was presented both before and after the CBM procedure. Participants who read the positive statements made more positive resolutions to the scrambled sentences, while participants who read the negative statements made more negative resolutions. Thus, the appropriate positive and negative interpretative biases were induced by the CBM procedure. However, significant mood changes also occurred following CBM. In Experiment 2, a musical mood induction procedure was presented with depressing or elating music. As before, a scrambled sentence test was presented both before and after the musical mood induction. Mood changed in accordance with the valence of the music to the same extent as with CBM. Critically however, performance on the scrambled sentence task did not change for both groups. This demonstrates that a change in mood state is not sufficient for a change in cognitive bias to occur.     

Study of posed emotion in facial EMG asymmetry

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

EMG reactions of mimetic muscles after repeated presentation of pictures with positive, negative and neutral content]

Twenty male subjects (Ss) were repeatedly confronted for five seconds to pictures with positive, negative and neutral valence. During the picture presentation facial EMG-reactions of five mimic muscles (m. frontalis lateralis, m. corrugator supercilii, m. orbicularis oculi, m. zygomaticus major on the right and left side of the face) were recorded. In addition, heart rate was measured. It could be shown that during repeated presentation of pictures with positive valence the m. orbicularis oculi and the m. zygomaticus major on both sides of the face yielded enhanced average EMG-reactions as compared to the repeated presentation of pictures with negative and neutral valence. During presentation of pictures with negative valence the m. frontalis lateralis and the m. corrugator supercilii revealed enhanced EMG-reactions as compared to the repeated presentation of pictures with positive valence. Furthermore, it could be shown that during the repeated presentation of pictures with positive valence those facial muscles which mainly react during confrontation with pictures of positive valence showed a continuous decrease of EMG-activity. Facial muscles which mainly react during the presentation of pictures with negative valence do not show a continuous decrease in EMG-activity during the course of the repeated presentation of pictures with negative valence. Additionally, the EMG-activity of the m. zygomaticus major on the right and lift side of the face do not differ with respect to the mean activity and the time course during confrontation of pictures with positive valence. The m. orbicularis oculi yielded enhanced EMG-reactions during the presentation of pictures with positive valence as compared to both m. zygomaticus major muscles. The present results are discussed with respect to psychobiological theories concerning facial expression.     

Cerebellum and processing of negative facial emotions: cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.     

Unequal impairment in the recognition of positive and negative emotions after right hemisphere lesions: a left hemisphere bias for happy faces

The processing of several important aspects of a human face was investigated in a single patient (LZ), who had a large infarct of the right hemisphere involving the parietal, and temporal lobes with extensions into the frontal region. LZ showed selective problems with recognizing emotional expressions, whereas she was flawless in recognizing gender, familiarity, and identity. She was very poor in recognizing negative facial expressions (fear, disgust, anger, sadness), but scored as well as the controls on the positive facial expression of happiness. However, in two experiments using both static and dynamic face stimuli, we showed that LZ also did not have a proper notion of what a facial expression of happiness looks like, and could not adequately apply this label. We conclude that the proper recognition of both negative and positive facial expressions relies on the right hemisphere, and that the left hemisphere produces a default state resulting in a bias towards evaluating expressions as happy. We discuss the implications of the current findings for the main models that aim to explain hemispheric specializations for processing of positive and negative emotions.     

Hemisphere Inactivation and Mood-State Changes

Mood-state changes were studied during a sodium Amytal testing procedure in epilepsy patients with unilateral temporal lobe foci. The results showed that inactivation of the left hemisphere, but not the right hemisphere, produced a negative mood state. This decline in mood was not specifically related to side of focus or sex. As expected, the inactivation of either hemisphere also lead to an impairment in memory performance. This impairment was somewhat worse during a left than a right hemisphere inactivation. Furthermore, patients with left hemisphere foci showed a lower memory performance than patients with a right-hemisphere lesion. These results suggest (a) a hemispheric specialization for emotion that underlie changes in mood and (b) a discrepancy between mood states at encoding (during inactivation) and retrieval (after inactivation).     

Cerebellum and processing of negative facial emotions: Cerebellar transcranial DC stimulation specifically enhances the emotional recognition of facial anger and sadness

Some evidence suggests that the cerebellum participates in the complex network processing emotional facial expression. To evaluate the role of the cerebellum in recognising facial expressions we delivered transcranial direct current stimulation (tDCS) over the cerebellum and prefrontal cortex. A facial emotion recognition task was administered to 21 healthy subjects before and after cerebellar tDCS; we also tested subjects with a visual attention task and a visual analogue scale (VAS) for mood. Anodal and cathodal cerebellar tDCS both significantly enhanced sensory processing in response to negative facial expressions (anodal tDCS, p=.0021; cathodal tDCS, p=.018), but left positive emotion and neutral facial expressions unchanged (p>.05). tDCS over the right prefrontal cortex left facial expressions of both negative and positive emotion unchanged. These findings suggest that the cerebellum is specifically involved in processing facial expressions of negative emotion.     

Differential cognitive response to a mood challenge following successful cognitive therapy or pharmacotherapy for unipolar depression

This study examined the nature of cognitive reactivity to mood changes in formerly depressed patients. Patients who recovered either through cognitive-behavior therapy (CBT; N = 25) or through pharmacotherapy (PT; N = 29) completed self-reported ratings of dysfunctional attitudes before and after a negative mood induction procedure. In response to similar levels of induced sad mood, PT patients showed a significant increase in dysfunctional cognitions compared with patients in the CBT group. To evaluate the effects of such cognitive reactivity on the subsequent course of depression, follow-up analyses reassessed 30 patients several years after initial testing. Results indicated that patients' reactions to the mood induction procedure were predictive of depressive relapse. These findings argue for differential effects of treatment on cognitive reactivity to mood induction and for the link between such reactivity and risk for later depressive relapse.     

The valence-specific laterality effect in free viewing conditions: The influence of sex, handedness, and response bias

The right hemisphere has often been viewed as having a dominant role in the processing of emotional information. Other evidence indicates that both hemispheres process emotional information but their involvement is valence specific, with the right hemisphere dealing with negative emotions and the left hemisphere preferentially processing positive emotions. This has been found under both restricted (Reuter-Lorenz & Davidson, 1981) and free viewing conditions (Jansari, Tranel, & Adophs, 2000). It remains unclear whether the valence-specific laterality effect is also sex specific or is influenced by the handedness of participants. To explore this issue we repeated Jansari et al.'s free-viewing laterality task with 78 participants. We found a valence-specific laterality effect in women but not men, with women discriminating negative emotional expressions more accurately when the face was presented on the left-hand side and discriminating positive emotions more accurately when those faces were presented on the right-hand side. These results indicate that under free viewing conditions women are more lateralised for the processing of facial emotion than are men. Handedness did not affect the lateralised processing of facial emotion. Finally, participants demonstrated a response bias on control trials, where facial emotion did not differ between the faces. Participants selected the left-hand side more frequently when they believed the expression was negative and the right-hand side more frequently when they believed the expression was positive. This response bias can cause a spurious valence-specific laterality effect which might have contributed to the conflicting findings within the literature.     

The joint influence of mood and a cognitively demanding task on risk-taking

This study investigates a mood regulation-based reconciliation of prior findings in the mood maintenance and information processes literatures about the impact of negative mood state on risktaking judgment. Participants were administered a negative mood state induction using a standardized film clip procedure and subsequently completed a measure of risk-taking judgment under one of three conditions: (1) immediately following the mood induction, (2) following a 5 min no-task delay period, or (3) following performance of a cognitively demanding task. As expected, participants who made risk judgments after the performance of the cognitively demanding task showed higher level of recovery from the negative mood induction (i.e., increased positive mood and decreased negative mood) and lower levels of risk-taking judgment than participants in the delayed condition. Additional analyses showed the risk-taking judgments were explained by mood change after the interpolated task. These findings reconcile previous inconsistencies between the two perspectives. Implications for future research on the restorative role of cognitive task performance as a mood regulation strategy are discussed.     

Recognition of facial expressions of emotions in criminal and non-criminal psychopaths: Valence-specific hypothesis

IntroductionPsychopaths with the dominant reduced interpersonal and affective ability are characterized by the hypofunction of the right hemisphere, while psychopaths with the dominant impulsivity and antisocial behavior are characterized by the hyperfunction of the left hemisphere. The assumption is that this interhemispheric imbalance in a psychopath will also be reflected in the recognition of facial emotional expressions.ObjectiveThe objective is to examine the lateralization of facial expressions of positive and negative emotions as well as processing of facial expressions of emotions in criminal and non-criminal psychopaths.Participants48 male participants age 24–40 were voluntarily recruited from the psychiatric hospital in Nis, Serbia.Stimuli48 black-and-white photographs in two separate tasks were used for the stimulation with central and lateral exposition.ResultsCriminality is related to the reduced recognition of facial expression of surprise and not necessarily to psychopathy, whereas reduced recognition of facial expression of fear is related to psychopathy, but not criminality. Valence-specific hypothesis has not been confirmed for positive and negative emotions in criminal and non-criminal psychopaths and non-psychopaths, but it was shown that positive emotions are equally well processed in both hemispheres, whereas negative emotions are more successfully processed in the left hemisphere.     

Hemisphere differences in the mood state-dependent effect for recognition of emotional faces

Forty subjects viewed 10 pictures of facial expressions of emotion while they experienced a happy mood and 10 pictures while they experienced a sad mood. Later, while re-experiencing either a happy or sad mood, they were tested for recognition of these 20 target pictures intermixed with 20 distractors. Recognition of the 10 pictures seen earlier in a disparate mood was impaired significantly when they were presented at testing to the right hemisphere, but not when presented to the left. The right hemisphere appears to store the subject's mood as an integral part of a memory representation for an emotionally expressive face. When that face is presented at testing to the right hemisphere, recognition depends on whether the subject's test mood matches the mood stored in the representation. In contrast, the left hemisphere appears to store the subject's mood separately from encoded visual information about a face, and so recognition of a face presented at testing to the left hemisphere is unaffected by changes in mood.     

A valence-specific lateral bias for discriminating emotional facial expressions in free field

Findings from subjects with unilateral brain damage, as well as from normal subjects studied with tachistoscopic paradigms, argue that emotion is processed differently by each brain hemisphere. An open question concerns the extent to which such lateralised processing might occur under natural, freeviewing conditions. To explore this issue, we asked 28 normal subjects to discriminate emotions expressed by pairs of faces shown side-by-side, with no time or viewing constraints. Images of neutral expressions were shown paired with morphed images of very faint emotional expressions (happiness, surprise, disgust, fear, anger, or sadness). We found a surprising and robust laterality effect: When discriminating negative emotional expressions, subjects performed significantly better when the emotional face was to the left of the neutral face; conversely, when discriminating positive expressions, subjects performed better when the emotional face was to the right. We interpret this valence-specific laterality effect as consistent with the idea that the right hemisphere is specialised to process negative emotions, whereas the left is specialised to process positive emotions. The findings have important implications for how humans perceive facial emotion under natural conditions.     

“The threat is in the head,not in the legs”: Activating negative age stereotypes generates extra cognitive load during walking

ObjectiveActivating negative age stereotypes has been consistently shown to impair cognitive performance in older adults, but not motor performance, especially on mobility tasks. We tested the hypothesis that older adults may still experience stereotype threat, even if mobility performance is not affected. To do so, we examined whether inducing negative stereotypes may increase cognitive load during a walking task.MethodThis question was investigated in a dual-task paradigm: older adults performed simultaneously a walking task and a Stroop task, in stereotype and control conditions.ResultsResults showed that the stereotype induction did not affect walking parameters but decreased performance on the Stroop task, indicating that this induction increased cognitive load during walking.DiscussionThese results suggest that negative age stereotypes may be damaging even if walking parameters are not affected, by altering older adults' attention to their walking environment. We conclude by highlighting theoretical and practical implications.     

Cradling side preference is associated with lateralized processing of baby facial expressions in females

Women’s cradling side preference has been related to contralateral hemispheric specialization of processing emotional signals; but not of processing baby’s facial expression. Therefore, 46 nulliparous female volunteers were characterized as left or non-left holders (HG) during a doll holding task. During a signal detection task they were then asked to detect the emotional baby faces in a series of baby portraits with neutral and emotional facial expressions, presented either to the left or the right visual field (VFP). ANOVA revealed a significant HG × VFP interaction on response bias data (p < .05). Response bias was lowest when emotional baby faces were presented in the visual field of cradling side preference, suggesting that women’s cradling side preference may have evolved to save cognitive resources during monitoring emotional baby face signals.     

Attentional selection is biased toward mood-congruent stimuli

One can exert significant volitional control over the attentional filter so that stimuli that are consistent with one's explicit goals are more likely to receive attention and become part of one's conscious experience. Here we pair a mood induction procedure with an inattentional blindness task to show that one's current mood has a similar influence on attention. A positive, negative, or neutral mood manipulation was followed by an attentionally demanding multiple-object tracking task. During the tracking task, participants were more likely to notice an unexpected face when its emotional expression was congruent with participants' mood. This was particularly true for the frowning face, which was detected almost exclusively by participants in the sad mood induction condition. This attentional bias toward mood-congruent stimuli provides evidence that one's temporary mood can influence the attentional filter, thereby affecting the information that one extracts from, and how one experiences the world.     

Stereotype susceptibility in children: effects of identity activation on quantitative performance

A growing body of research indicates that the activation of negative stereotypes can impede cognitive performance in adults, whereas positive stereotypes can facilitate cognitive performance. In two studies, we examined the effects of positive and negative stereotypes on the cognitive performance of children in three age groups: lower elementary school, upper elementary school, and middle school. Very young children in the lower elementary grades (kindergarten–grade 2) and older children in the middle school grades (grades 6–8) showed shifts in performance associated with the activation of positive and negative stereotypes; these shifts were consistent with patterns previously reported for adults. The subtle activation of negative stereotypes significantly impeded performance, whereas the subtle activation of positive stereotypes significantly facilitated performance. Markedly different effects were found for children in the upper elementary grades (grades 3–5). These results suggest that the development of stereotype susceptibility is a critical domain for understanding the connection between stereotypes and individual behavior.     

Republican Voters Prefer Candidates Who Have Conservative‐Looking Faces: New Evidence From Exit Polls

Research shows people share common political facial stereotypes: They associate faces with political ideologies. Moreover, given that many voters rely on party affiliation, political ideology, and appearances to select political candidates, we might expect that political facial stereotypes would sway voting preferences and, by extension, the share of votes going to each candidate in an election. And yet few studies have examined whether having a stereotypically conservative‐looking (or liberal‐looking) face predicts a candidate's vote shares. Using data from U.S. election exit polls, we show that the Republican voters within each state are more likely to vote for a candidate (even a Democrat) the more that person has a stereotypically Republican‐looking face. By contrast, the voting choices of the Democratic voters within each state are unrelated to political facial stereotypes. Moreover, we show that the relationship between political facial stereotypes and voting does not depend on state‐level ideology: Republican voters in both right‐leaning (“red”) and left‐leaning (“blue”) states are more likely to vote for candidates with conservative‐looking faces. These results have several important practical and theoretical implications concerning the nature and impact of political facial stereotypes, which we discuss.