Emotional context modulates micro-expression processing as reflected in event-related potentials

Horses (Equus caballus) facial micro-expressions: insight into discreet social information

Facial micro-expressions are facial expressions expressed briefly (less than 500 ms) and involuntarily. Described only in humans, we investigated whether micro-expressions could also be expressed by non-human animal species. Using the Equine Facial action coding system (EquiFACS), an objective tool based on facial muscles actions, we demonstrated that a non-human species, Equus caballus, is expressing facial micro-expressions in a social context. The AU17, AD38 and AD1 were selectively modulated as micro-expression-but not as standard facial expression (all durations included)-in presence of a human experimenter. As standard facial expressions, they have been associated with pain or stress but our results didn't support this association for micro-expressions which may convey other information. Like in humans, neural mechanisms underlying the exhibit of micro-expressions may differ from those of standard facial expressions. We found that some micro-expressions could be related to attention and involved in the multisensory processing of the 'fixed attention' observed in horses' high attentional state. The micro-expressions could be used by horses as social information in an interspecies relationship. We hypothesize that facial micro-expressions could be a window on transient internal states of the animal and may provide subtle and discreet social signals.

The effect of facial attractiveness on micro-expression recognition

Micro-expression (ME) is an extremely quick and uncontrollable facial movement that lasts for 40–200 ms and reveals thoughts and feelings that an individual attempts to cover up. Though much more difficult to detect and recognize, ME recognition is similar to macro-expression recognition in that it is influenced by facial features. Previous studies suggested that facial attractiveness could influence facial expression recognition processing. However, it remains unclear whether facial attractiveness could also influence ME recognition. Addressing this issue, this study tested 38 participants with two ME recognition tasks in a static condition or dynamically. Three different MEs (positive, neutral, and negative) at two attractiveness levels (attractive, unattractive). The results showed that participants recognized MEs on attractive faces much quicker than on unattractive ones, and there was a significant interaction between ME and facial attractiveness. Furthermore, attractive happy faces were recognized faster in both the static and the dynamic conditions, highlighting the happiness superiority effect. Therefore, our results provided the first evidence that facial attractiveness could influence ME recognition in a static condition or dynamically.

Emotional context effect on recognition of varying facial emotion expression intensities in depression

BACKGROUND

Previous research has indicated that Major Depressive Disorder (MDD) patients have deficits in the process of facial emotion recognition. In most of these studies, isolated emotional faces were used, and the effect of the surrounding context of the face was neglected. We aimed to investigate how context emotion (sad or happy) affects facial emotion recognition and whether this effect is different in depressive individuals compared to the control group.

METHODS

Happy, sad, neutral facial expressions with congruent and incongruent visual contexts were presented to 51 MDD patients and 42 matched healthy controls. Emotional facial expressions are presented as morphs gradually expressing happiness or sadness with 40% and 80% intensity levels. Mean reaction time, mean accuracy rate, and mean emotion intensity rating score was calculated for each condition.

RESULTS

The performances on facial emotion intensity rating and accuracy rate were similar between MDD patients and controls. MDD patients were slower to recognize all facial emotions and to recognize facial emotions with emotionally incongruent backgrounds compared to congruent ones.

LIMITATIONS

Antidepressant therapy of patients might have affected our results.

CONCLUSIONS

Emotional contextual features have an important role in facial emotion recognition but this effect is independent of depression. Longer reaction time in depression may be related to some cognitive impairments.

Arithmetic performance is modulated by cognitive reappraisal and expression suppression: Evidence from behavioral and ERP findings

Previous studies have shown that negative emotional experiences are detrimental to individual's arithmetic performance, and no study has investigated whether such negative influence can be improved through emotional regulation. This study aimed to explore the relationship between emotion regulation and individual's performance in completing arithmetic problem verification task. Participants were asked to complete arithmetic problem verification task using the down-up strategy (e.g., doing 30 × 70 = 2100 for 34 × 67), under neutral, happy, and fear priming conditions, during which they were asked to regulate their emotional experience by using cognitive reappraisal or expressive suppression. Behavioral results showed that, under happy priming condition, cognitive reappraisal (but not expression suppression) contributed to improving individual's estimation speed. Additionally, under happy and fear priming conditions, cognitive reappraisal (vs. expression suppression) reduced individuals' emotional experience intensity. The arithmetic problem verification task-related ERP results showed that the P1 amplitudes elicited by using cognitive reappraisal (vs. freely view) were larger under happy and fear priming conditions, but the P1 amplitudes elicited by using expression suppression were larger only under happy condition. Meanwhile, the corresponding N170 amplitudes were smaller when using cognitive reappraisal and expression suppression (vs. freely view). Additionally, using cognitive reappraisal (vs. expression suppression) cost less cognitive resource (smaller LPC amplitudes). The present study indicated that both cognitive reappraisal and expression suppression contributed to improving individual's arithmetic performance, and the regulation effect of cognitive reappraisal was better than that of expression suppression.

Implicit happy and fear experience contributes to computational estimation strategy execution: Behavioral and neurophysiological evidence

Previous study have explored the influence of explicit emotion priming on computational estimation strategy execution, but the corresponding influence of implicit emotion priming still remains unknown. The present study aimed to solve this problem. Participants were asked to complete two-digit multiplication computational estimation task, under different implicit emotion priming conditions (gender judgment task). In the two-digit multiplication computational estimation task, the computational estimation question was presented in the middle of the screen, meanwhile, two alternative answers were presented side by side at the bottom of the screen, participants were required to select which answer is correct, by using the down-up strategy (e.g., doing 30 × 50 = 1500 for 34 × 46). Behavioral results showed that the response speed under implicit happy and fear (vs. neutral and angry) priming conditions was quicker, and the accuracy under different priming conditions showed no significant difference. The ERP results showed that the influence of implicit emotion priming on computational estimation strategy execution consisted of two phases: in the first phase, the N1 amplitudes elicited by completing the multiplication computational estimation task were smaller under implicit fear (vs. angry) priming condition; in the second phase, the corresponding P2 amplitudes under implicit happy (vs. fear) priming condition were smaller. The present study indicated that implicit happy and fear experience contributed to complete computational estimation tasks, suggesting that implicit negative emotional (e.g., fear) experience was not always detrimental to computational estimation strategy execution.

Recognition Characteristics of Facial and Bodily Expressions: Evidence From ERPs

In the natural environment, facial and bodily expressions influence each other. Previous research has shown that bodily expressions significantly influence the perception of facial expressions. However, little is known about the cognitive processing of facial and bodily emotional expressions and its temporal characteristics. Therefore, this study presented facial and bodily expressions, both separately and together, to examine the electrophysiological mechanism of emotional recognition using event-related potential (ERP). Participants assessed the emotions of facial and bodily expressions that varied by valence (positive/negative) and consistency (matching/non-matching emotions). The results showed that bodily expressions induced a more positive P1 component and a shortened latency, whereas facial expressions triggered a more negative N170 and prolonged latency. Among N2 and P3, N2 was more sensitive to inconsistent emotional information and P3 was more sensitive to consistent emotional information. The cognitive processing of facial and bodily expressions had distinctive integrating features, with the interaction occurring in the early stage (N170). The results of the study highlight the importance of facial and bodily expressions in the cognitive processing of emotion recognition.

Emotional valence modulates arithmetic strategy execution in priming paradigm: an event-related potential study

Combined with the prime paradigm, the present study aimed to explore the influence of emotion (anger, fear, happiness, and neutral) on performing multiplication estimation. Participants were asked to complete a two-digit multiplication estimation task using the down-up strategy (e.g., doing 20 × 80 = 1600 for 24 × 79). Behavioral results showed that the reaction time for completing multiplication estimation tasks under happy conditions was shorter than for those under anger and fear, and it was shorter under neutral than under fearful conditions. The ERP results showed that about 100 ms after multiplication estimation task onset, multiplication estimation execution in the context of happiness (vs. neutral) elicited smaller P1 amplitudes; about 170 ms after multiplication estimation task onset, the N170 amplitudes elicited by multiplication estimation strategy execution under different emotional priming conditions showed no significant differences. The above results showed that the impact of emotion priming demonstrates the occurrence of a dynamic process when participants use a specified strategy to complete the multiplication estimation task. The present study revealed that emotional valence modulated arithmetic strategy execution, suggesting the role of different emotions should be fully considered in similar study.

Brain Activation in Contrasts of Microexpression Following Emotional Contexts

The recognition of microexpressions may be influenced by emotional contexts. The microexpression is recognized poorly when it follows a negative context in contrast to a neutral context. Based on the behavioral evidence, we predicted that the effect of emotional contexts might be dependent on neural activities. Using the synthesized microexpressions task modified from the Micro-Expression Training Tool (METT), we performed an functional MRI (fMRI) study to compare brain response in contrasts of the same targets following different contexts. Behaviorally, we observed that the accuracies of target microexpressions following neutral contexts were significantly higher than those following negative or positive contexts. At the neural level, we found increased brain activations in contrasts of the same targets following different contexts, which reflected the discrepancy in the processing of emotional contexts. The increased activations implied that different emotional contexts might differently influence the processing of subsequent target microexpressions and further suggested interactions between the processing of emotional contexts and of microexpressions.

Ecological micro-expression recognition characteristics of young adults with subthreshold depression

The micro-expression (ME) processing characteristics of patients with depression has been studied but has not been investigated in people with subthreshold depression. Based on this, by adopting the ecological MEs recognition paradigm, this study aimed to explore ME recognition in people with subthreshold depression. A 4 (background expression: happy, neutral, sad and fearful) × 4 (ME: happy, neutral, sad, and fearful) study was designed; two groups of participants (experimental group with subthreshold depression vs. healthy control group, 32 participants in each group) were asked to complete the ecological ME recognition task, and the corresponding accuracy (ACC) and reaction time (RT) were analyzed. Results: (1) Under different background conditions, recognizing happy MEs had the highest ACC and shortest RT. (2) There was no significant difference in the ACC and RT between experimental and control groups. (3)In different contexts, individuals with subthreshold depression tended to misjudge neutral, sad, and fearful MEs as happy, while neutral MEs were misjudged as sad and fearful. (4) The performance of individuals with subthreshold depression in the ecological ME recognition task were influenced by the type of ME; they showed highest ACC and shortest RT when recognizing happy MEs (vs. the other MEs). Conclusions: (1) The performance of individuals’ ecological ME recognition were influenced by the background expression, and this embodied the need for ecological ME recognition. (2) Individuals with subthreshold depression showed normal ecological ME recognition ability. (3) In terms of misjudgment, individuals with subthreshold depression showed both positive and negative bias, when completing the ecological ME recognition task. (4) Compared with the other MEs, happy MEs showed an advantage recognition effect for individuals with subthreshold depression who completed the ecological ME recognition task.

A False Trail to Follow: Differential Effects of the Facial Feedback Signals From the Upper and Lower Face on the Recognition of Micro-Expressions

Micro-expressions, as fleeting facial expressions, are very important for judging people’s true emotions, thus can provide an essential behavioral clue for lie and dangerous demeanor detection. From embodied accounts of cognition, we derived a novel hypothesis that facial feedback from upper and lower facial regions has differential effects on micro-expression recognition. This hypothesis was tested and supported across three studies. Specifically, the results of Study 1 showed that people became better judges of intense micro-expressions with a duration of 450 ms when the facial feedback from upper face was enhanced via a restricting gel. Additional results of Study 2 showed that the recognition accuracy of subtle micro-expressions was significantly impaired under all duration conditions (50, 150, 333, and 450 ms) when facial feedback from lower face was enhanced. In addition, the results of Study 3 also revealed that blocking the facial feedback of lower face, significantly boosted the recognition accuracy of subtle and intense micro-expressions under all duration conditions (150 and 450 ms). Together, these results highlight the role of facial feedback in judging the subtle movements of micro-expressions.