Neutral Faces Research Articles

Event-related potential response to drivers' facial expressions in an online car-hailing scene.

Recognizing facial expressions is crucial for adaptive social interaction. Prior empirical research on facial expression processing has primarily focused on isolated faces; however, facial expressions appear embedded in surrounding scenes in everyday life. In this study, we attempted to demonstrate how the online car-hailing scene affects the processing of facial expression. This study examined the processing of drivers' facial expressions in scenes by recording event-related potentials, in which neutral or happy faces embedded in online car-hailing orders were constructed (with type of vehicle, driver rating, driver surname, and level of reputation controlled). A total of 35 female volunteers participated in this experiment and were asked to judge which facial expressions that emerged in scenes of online car-hailing were more trustworthy. The results revealed an interaction between facial expression scenes, brain areas, and electrode sites in the late positive potential, which indicated that happy faces elicited larger amplitudes than did neutral ones in the parietal areas and that scenes with happy facial expressions had shorter latencies than did those with neutral ones. As expected, the late positive potential evoked by happy facial expressions in a scene was larger than that evoked by neutral ones, which reflected motivated attention and motivational response processes. This study highlights the importance of scenes as context in the study of facial expression processing.

The effect of dichotic music presentation on ratings of emotional facial expressions

Music has a cross-modal influence on the emotional appraisal of pictures, probably due to a misattribution of emotion from music to the visually perceived images. Moreover, dichotic listening studies have demonstrated a left-ear (right-hemisphere) advantage for processing emotional and/or musical stimuli. The present study investigated the role of laterality in cross-modal affect misattribution: that is, whether visual judgments of emotion would be affected differently depending on which ear was presented with music via the dichotic listening task. Participants rated the emotionality of happy, sad, and neutral faces while listening to happy or sad music in one ear and white noise in the other. Baseline ratings without music were used as a comparison to see whether and how emotionality judgments shifted in the music conditions. As predicted, the results showed that happy music played to the left ear had a stronger cross-modal influence on ratings of sad faces than the same music played to the right ear. Furthermore, sad music affected the ratings of all faces regardless of whether it was played to the left or right ear. These results do not fully align with any given lateralized model of emotion processing, suggesting that other factors such as negativity bias may play a role.

The effect of emotional uncertainty on attentional bias toward neutral infant faces in adults.

Recent studies have found that adults have stronger attentional bias toward neutral infant faces than emotional (positive or negative) infant faces. This phenomenon may derive from uncertainty over neutral expressions. To test this hypothesis, we recruited 176 participants to examine the relationship between their attentional bias toward neutral infant faces (with neutral adult faces as a comparison baseline) and their level of certainty in their appraisal of emotional valence through eye-tracking indices. The results showed that participants had a longer dwell time and higher fixation counts for infant faces than for adult faces and that a more uncertain appraisal of facial expressions positively predicted attentional bias toward neutral infant faces. Therefore, this study preliminarily demonstrates that emotional uncertainty heightens adults' attentional bias toward infant faces with neutral expressions.

Social threat and safety learning in individuals with adverse childhood experiences: electrocortical evidence on face processing, recognition, and working memory

ABSTRACT Background: Adverse childhood experiences (ACEs) are often associated with stress and anxiety-related disorders in adulthood, and learning and memory deficits have been suggested as a potential link between ACEs and psychopathology. Objective: In this preregistered study, the impact of social threat learning on the processing, encoding, and recognition of unknown faces as well as their contextual settings was measured by recognition performance and event-related brain potentials. Method: Sixty-four individuals with ACEs encoded neutral faces within threatening or safe context conditions. During recognition, participants had to decide whether a face was new or had been previously presented in what context (item-source memory), looking at old and new faces. For visual working memory, participants had to detect changes in low and high load conditions during contextual threat or safety. Results: Results showed a successful induction of threat expectation in persons with ACEs. In terms of face and source recognition, overall recognition of safe and new faces was better compared to threatening face-compounds, with more socially anxious individuals having an advantage in remembering threatening faces. For working memory, an effect of task load was found on performance, irrespective of threat or safety context. Regarding electrocortical activity, an old/new recognition effect and threat-selective processing of face–context information was observed during both encoding and recognition. Moreover, neural activity associated with change detection was found for faces in a threatening context, but only at high task load, suggesting reduced capacity for faces in potentially harmful situations when cognitive resources are limited. Conclusion: While individuals with ACE showed intact social threat and safety learning overall, threat-selective face processing was observed for item/source memory, and a threatening context required more processing resources for visual working memory. Further research is needed to investigate the psychophysiological processes involved in functional and dysfunctional memory systems and their importance as vulnerability factors for stress-related disorders.

Older adults get masked emotion priming for happy but not angry faces: evidence for a positivity effect in early perceptual processing of emotional signals

ABSTRACT In higher-level cognitive tasks, older compared to younger adults show a bias towards positive emotion information and away from negative information (a positivity effect). It is unclear whether this effect occurs in early perceptual processing. This issue is important for determining if the positivity effect is due to automatic rather than controlled processing. We tested this with older and younger adults on a positive/negative face emotion valence classification task using masked priming. Positive (happy) and negative (angry) face targets were preceded by masked repetition or valence primes with neutral face baselines. In Experiment 1, 30 younger and 30 older adults were tested with 50 ms primes. Younger adults showed repetition priming for both positive and negative targets. Older adults showed repetition priming for positive but not negative targets. Neither group showed valence priming. In Experiment 2, 30 older and 29 younger adults were tested with longer duration primes. Younger adults showed repetition priming for both positive and negative emotions, and no valence priming. Older adults only showed repetition and valence priming for positive targets. We proposed older adults’ lack of angry face priming was due to an early attention orienting strategy favouring happy expressions at the expense of angry ones.

Pain E-motion Faces Database (PEMF): Pain-related micro-clips for emotion research

A large number of publications have focused on the study of pain expressions. Despite the growing knowledge, the availability of pain-related face databases is still very scarce compared with other emotional facial expressions. The Pain E-Motion Faces Database (PEMF) is a new open-access database currently consisting of 272 micro-clips of 68 different identities. Each model displays one neutral expression and three pain-related facial expressions: posed, spontaneous-algometer and spontaneous-CO2 laser. Normative ratings of pain intensity, valence and arousal were provided by students of three different European universities. Six independent coders carried out a coding process on the facial stimuli based on the Facial Action Coding System (FACS), in which ratings of intensity of pain, valence and arousal were computed for each type of facial expression. Gender and age effects of models across each type of micro-clip were also analysed. Additionally, participants’ ability to discriminate the veracity of pain-related facial expressions (i.e., spontaneous vs posed) was explored. Finally, a series of ANOVAs were carried out to test the presence of other basic emotions and common facial action unit (AU) patterns. The main results revealed that posed facial expressions received higher ratings of pain intensity, more negative valence and higher arousal compared with spontaneous pain-related and neutral faces. No differential effects of model gender were found. Participants were unable to accurately discriminate whether a given pain-related face represented spontaneous or posed pain. PEMF thus constitutes a large open-source and reliable set of dynamic pain expressions useful for designing experimental studies focused on pain processes.

Interactions between text content and emoji types determine perceptions of both messages and senders

Emoji increasingly feature alongside written language in interpersonal communication. Boutet et al. (2021) showed that negative-face emoji led to a negativity effect on perceptions of message tone and senders' mood. We extended their design, considering the role of non-face emoji and the impact of text content and emoji on message clarity. We utilised a 3 (sentence valence: negative, neutral, positive) × 5 (emoji type: no emoji, negative face, neutral face, positive face, object emoji) quasi-experimental design and online survey method. Sixty participants each processed 60 stimuli counterbalanced across conditions, rating messages' emotional tone and clarity, and senders’ warmth and emotional state. Cumulative link mixed models were used to analyse responses. We found that sentence valence and emoji type interact, influencing message emotionality and clarity, and perceived sender warmth and state. The congruency of text and emoji was particularly important; results showed that incongruent emoji detracted from message clarity vs. no emoji (or congruent emoji). Congruent emoji typically amplified emotional perceptions of messages and senders. Object emoji were most influential when text was either neutral or positive. Results were consistent with models such as the EASI framework (Van Kleef, 2009), and suggest that compositionality extends to representations of text + emoji.

Working memory updating in individuals with bipolar and unipolar depression: fMRI study

Understanding neurobiological characteristics of cognitive dysfunction in distinct psychiatric disorders remains challenging. In this secondary data analysis, we examined neurobiological differences in brain response during working memory updating among individuals with bipolar disorder (BD), those with unipolar depression (UD), and healthy controls (HC). Individuals between 18–45 years of age with BD (n = 100), UD (n = 109), and HC (n = 172) were scanned using fMRI while performing 0-back (easy) and 2-back (difficult) tasks with letters as the stimuli and happy, fearful, or neutral faces as distractors. The 2(n-back) × 3(groups) × 3(distractors) ANCOVA examined reaction time (RT), accuracy, and brain activation during the task. HC showed more accurate and faster responses than individuals with BD and UD. Difficulty-related activation in the prefrontal, posterior parietal, paracingulate cortices, striatal, lateral occipital, precuneus, and thalamic regions differed among groups. Individuals with BD showed significantly lower difficulty-related activation differences in the left lateral occipital and the right paracingulate cortices than those with UD. In individuals with BD, greater difficulty-related worsening in accuracy was associated with smaller activity changes in the right precuneus, while greater difficulty-related slowing in RT was associated with smaller activity changes in the prefrontal, frontal opercular, paracingulate, posterior parietal, and lateral occipital cortices. Measures of current depression and mania did not correlate with the difficulty-related brain activation differences in either group. Our findings suggest that the alterations in the working memory circuitry may be a trait characteristic of reduced working memory capacity in mood disorders. Aberrant patterns of activation in the left lateral occipital and paracingulate cortices may be specific to BD.

Diminished Visual Attention to Emotional Faces Is Associated with Poor Emotional Valence Perception in Frontotemporal Dementia

Aim: The current study examined whether visual attention to emotional facial expressions is lower in individuals with frontotemporal dementia (FTD) compared to healthy controls, and whether visual attention to emotional facial expressions is associated with the ability to perceive others’ emotional valence accurately. Methods: Participants with FTD (n = 17) and healthy controls (n = 23) passively viewed pairs of emotional and neutral faces while their visual attention was measured using eye-tracking. A subsample of participants (n = 28) also completed an emotional valence perception task. Results: Individuals with FTD spent less time looking at emotional faces than healthy controls. However, there was no difference in the amount of time individuals with FTD spent looking at neutral faces as compared to healthy controls. In the subsample, less time spent looking at emotional faces (but not neutral faces) was associated with a less accurate perception of others’ emotional valence. Conclusion: Individuals with FTD displayed diminished visual attention to emotional facial expressions compared to healthy controls. Reduced attention towards emotional faces was associated with poorer emotional valence perception. Findings point toward diminished visual attention as potentially relevant for understanding oft-observed impairments in socioemotional functioning in FTD.

Emotional intelligence and attentional bias to emotional faces: Evidence of hypersensitivity towards emotion information

It has been proposed that emotional intelligence (EI) functions as a magnifier of emotional experience. This phenomenon, called the “hypersensitivity hypothesis,” predicts that high EI amplifies the emotional aspects of experience (Fiori & Ortony, 2021). We tested whether high EI individuals show stronger attention to emotional than neutral expressions with a dot-probe task in which participants (N = 155) had to report a letter appearing behind an emotional or a neutral face. A significant interaction EI by experimental condition showed an attentional bias towards emotional faces associated with high EI: individuals high on emotion understanding were faster to respond to cues replacing an emotional as compared to a neutral face, an effect that was not found for low-EI individuals. Results support that high EI individuals are particularly reactive to emotion information, confirming the basic assumptions of the hypersensitivity hypothesis. Implications for research on EI are discussed.

The consistency of self-reference and mother reference in social evaluation

In social interactions an individual's perception of others' facial expressions is usually influenced by the evaluation of personality traits, especially negative evaluations. We integrated social-appraisal contexts with self- and motherreferential processing in a Chinese cultural context to examine the effect of context, including different potencies and reference types, on the individual's emotional perceptual processes of others' facial expressions. We found that neutral faces presented in positive/negative self-referential and motherreferential contexts were perceived as more positive/more negative than were neutral faces presented in other-referential contexts. Event-related potential (ERP) data showed that self-referential and mother-referential negative contexts induced more pronounced early posterior negativity and late positive potential components than did other-referential contexts. However, these same contexts did not significantly affect the results of the positive ERP component that occurs approximately 100 ms after stimulus presentation (P1) and the negative deflection in wave amplitude that occurs around 170 ms after the presentation of a face (N170). These results suggest that social-behavioral appraisals related to self and mother can influence the individual's perception of an appraiser's facial emotions even when there is no personality trait appraisal.

Anxiety, fear extinction, and threat-related amygdala reactivity in children exposed to urban trauma

Introduction Childhood trauma is strongly associated with fear-related psychopathology, like anxiety and posttraumatic stress disorder (PTSD). Atypical fear extinction and neural responses to social threat (i.e., negative emotional faces) may serve as intermediate phenotypes preceding the emergence of fear-related psychopathology during childhood and adolescence. However, few studies have examined associations among these phenotypes in trauma-exposed youth. Methods 29 9-year-old children with high rates of trauma exposure (Mdn = 4, min = 0, max= 14 total events) completed a fear-potentiated startle paradigm assessing fear conditioning and extinction and an emotional faces functional magnetic resonance imaging (fMRI) task assessing neural responses to fearful and neutral faces. Results Overall amygdala response was positively associated with anxiety (peak coordinates: x = −30, y = −6, z = −24; Z = 3.54; pFWEcorrected = 0.011; k = 24 voxels) and fear-potentiated startle during early extinction (peak coordinates x = 28, y = −6, z = −18; Z = 3.50; pFWEcorrected = 0.012; k = 19 voxels). Across the session, amygdala reactivity to fearful faces increased (F(1, 29) = 4.427, p = .044) and was positively associated with fear-potentiated startle during early extinction (r = .56, p = .002). Conclusions We found a positive association between increasing amygdala response to threatening faces and fear load, that is, heightened fear-potentiated startle during early extinction, in trauma-exposed children. These fear-based intermediate phenotypes may share underlying amygdala circuits, such that hyperactivity may represent an early marker of anxiety risk in trauma-exposed youth.

Disentangling Identity and Pose for Facial Expression Recognition

Facial expression recognition (FER) is a challenging problem because the expression component is always entangled with other irrelevant factors, such as identity and head pose. In this work, we propose an identity and pose disentangled facial expression recognition (IPD-FER) model to learn more discriminative feature representation. We regard the holistic facial representation as the combination of identity, pose and expression. These three components are encoded with different encoders. For identity encoder, a well pre-trained face recognition model is utilized and fixed during training, which alleviates the restriction on specific expression training data in previous works and makes the disentanglement practicable on in-the-wild datasets. At the same time, the pose and expression encoder are optimized with corresponding labels. Combining identity and pose feature, a neutral face of input individual should be generated by the decoder. When expression feature is added, the input image should be reconstructed. By comparing the difference between synthesized neutral and expressional images of the same individual, the expression component is further disentangled from identity and pose. Experimental results verify the effectiveness of our method on both lab-controlled and in-the-wild databases and we achieve state-of-the-art recognition performance.

Effects of evaluative homogeneity in working memory

In four experiments, a change detection task using emotional (i.e., angry and happy) faces as stimuli was implemented to investigate the effects of evaluative congruency on working-memory performance and to replicate the angry-face benefit (i.e., better performance for angry compared to happy and neutral faces) found in former studies. Although results of the single experiments were heterogeneous, an overall analysis revealed better performance in trials with evaluatively congruent compared to evaluatively incongruent displays and an angry-face benefit. The congruency effect is in line with recent assumptions that evaluative-priming effects might arise from a mutual facilitation of simultaneously active evaluatively congruent concepts. Research on the angry-face benefit is enriched by the finding that the benefit was also found in control experiments using inverted faces. This result suggests that the effect is based on perceptual features of angry faces.

Cognitive mechanisms of the face context effect: An event related potential study of the effects of emotional contexts on neutral face perception

Face context effect refers to the influence of the emotional context on facial expression perception. Numerous empirical studies have explored the mechanisms of the face context effect, but no consistent conclusions have been drawn. Hence, we investigated the cognitive mechanisms of the face context effect using recordings of event-related potentials. In Experiment 1, we adopted the context-target paradigm to explore the mechanisms of the effect of context with different emotional valences on the neutral face perception (emotional valence-based face context effect). In Experiment 2, we explored the mechanisms of the effect of context with different emotional types on the neutral face perception (specific emotion-based face context effect). The results of Experiment 1 indicated that the participants were biased toward contextual valence when recognizing the emotional valence of neutral faces, and that the neutral target faces under emotional contexts with different valences induced significant differences in the P1, N170, and LPP amplitudes. In Experiment 2, the results of Experiment 2 indicated that the participants were biased toward specific contextual emotions when recognizing the emotion type of neutral faces, and that the neutral target faces under contexts of different emotional types induced significant differences in the LPP amplitude, but not in the P1 or N170 amplitude. We concluded that the emotional valence-based face context effect occurred in the early processing stage, whereas the specific emotion-based face context effect occurred in the late processing stage.

The effects of facial expressions on judgments of others when observing two-person confrontation scenes from a third person perspective.

When building personal relationships, it is important to select optimal partners, even based on the first meeting. This study was inspired by the idea that people who smile are considered more trustworthy and attractive. However, this may not always be true in daily life. Previous studies have used a relatively simple method of judging others by presenting a photograph of one person’s face. To move beyond this approach and examine more complex situations, we presented the faces of two people confronted with each other to participants and asked them to judge them from a third-person perspective. Through three experiments, participants were asked to judge which of the two persons was more appropriate for forming alliances, more trustworthy, or more attractive, respectively. In all experiments, images were shown for a short (500 ms) or a long time (5 s). In all three experiments, the results showed that participants were more likely to choose persons with happy faces than those with neutral, sad, or angry faces when the image presentation was short. Contrarily, the facial expressions did not affect those judgments when the image presentation was long. Instead, judgments were correlated with personality estimated from the model’s neutral face in a single-person presentation. These results suggest that although facial expressions can affect the judgments of others when observing two-person confrontations from a third-person perspective, when participants have more time to elaborate their judgments, they go beyond expressions.

Attentional load effects on emotional content in face working memory.

This study investigated the role of attentional resources in processing emotional faces in working memory (WM). Participants memorised two face arrays with the same emotion but different identities and were required to judge whether the test face had the same identity as one of the previous faces. Concurrently during encoding and maintenance, a sequence of high- or low-pitched tones (high load) or white noise bursts (low load) was presented, and participants were required to count how many low-tones were heard. Experiments 1 and 2 used an emotional and neutral test face, respectively. The results revealed a significant WM impairment for sad and angry faces in the high-load versus low-load condition but not for happy faces. In Experiment 1, participants remembered happy faces better than other emotional faces. In contrast, Experiment 2 showed that performance was poorer for happy than sad faces but not for angry faces. This evidence suggests that depleting attentional resources has less impact on WM for happy faces than other emotional faces, but also that differential effects on WM for emotional faces depend on the presence or absence of emotion in the probe face at retrieval.

Jointly Optimizing Expressional and Residual Models for 3D Facial Expression Removal

This article proposes a facial expression removal method to recover a 3D neutral face from a single 3D expressional or non-neutral face. We treat a 3D non-neutral face as the sum of its neutral one and the residual. This can be satisfied if the correspondence between 3D vertices of expressional faces and those of neutral faces is established. We propose a non-rigid deformation method to establish the correspondence between 3D faces. Then, according to algebra inequality, the minimization of a neutral face model can be replaced by the minimization of its upper bound, i.e., the errors of an expressional face model and a residual model. Thus, we co-optimize the representation errors of the latter two models and build the relationship between the representation coefficients of the two models. Given an expressional face as the input, its corresponding neutral face can be inferred by the associative representation parameters in these two models. In the testing stage, we use an iterative joint fitting scheme to obtain a more accurate recovery. Extensive experiments are conducted to evaluate our method. The results show that our method obtains considerably better performance than existing methods in terms of average root mean square errors and recognition rates, and also better visual effects.

Law Enforcement Officers' Ability to Recognize Emotions: The Role of Personality Traits and Basic Needs' Satisfaction.

Background: This study intended to explore the role of personality traits and basic psychological needs in law enforcement officers’ ability to recognize emotions: anger, joy, sadness, fear, surprise, disgust, and neutral. It was significant to analyze law enforcement officers’ emotion recognition and the contributing factors, as this field has been under-researched despite increased excessive force use by officers in many countries. Methods: This study applied the Big Five–2 (BFI-2), the Basic Psychological Needs Satisfaction and Frustration Scale (BPNSFS), and the Karolinska Directed Emotional Faces set of stimuli (KDEF). The data was gathered using an online questionnaire provided directly to law enforcement agencies. A total of 154 law enforcement officers participated in the study, 50.65% were females, and 49.35% were males. The mean age was 41.2 (age range = 22–61). In order to analyze the data, SEM and multiple linear regression methods were used. Results: This study analyzed variables of motion recognition, personality traits, and needs satisfaction and confirmed that law enforcement officers’ personality traits play a significant role in emotion recognition. Respondents’ agreeableness significantly predicted increased overall emotion recognition; conscientiousness predicted increased anger recognition; joy recognition was significantly predicted by extraversion, neuroticism, and agreeableness. This study also confirmed that law enforcement officers’ basic psychological needs satisfaction/frustration play a significant role in emotion recognition. Respondents’ relatedness satisfaction significantly predicted increased overall emotion recognition, fear recognition, joy recognition, and sadness recognition. Relatedness frustration significantly predicted decreased anger recognition, surprise recognition, and neutral face recognition. Furthermore, this study confirmed links between law enforcement officers’ personality traits, satisfaction/frustration of basic psychological needs, and emotion recognition, χ2 = 57.924; df = 41; p = 0.042; TLI = 0.929; CFI = 0.956; RMSEA = 0.042 [0.009–0.065]. Discussion: The findings suggested that agreeableness, conscientiousness, extraversion, and neuroticism play an essential role in satisfaction and frustration of relatedness needs, which, subsequently, link to emotion recognition. Due to the relatively small sample size, the issues of validity/reliability of some instruments, and other limitations, the results of this study should preferably be regarded with concern.

Different ways to forget: Electrophysiological mechanisms underlying item-method directed forgetting of angry and neutral faces.

Emotional stimuli, including faces, receive preferential processing and are consequently better remembered than neutral stimuli. Therefore, they may also be more resistant to intentional forgetting. The present study investigates the behavioral and electrophysiological consequences of instructions to selectively remember or forget angry and neutral faces. In an item-method directed forgetting experiment, angry and neutral faces were randomly presented to 25 student participants (4 males). Each face was followed by an instruction to either forget or remember it and the participants’ EEG was recorded. Later, recognition memory was unexpectedly tested for all items. Behaviorally, both hit and false alarm rates were higher for angry alike than for neutral faces. Directed forgetting occurred for neutral and angry faces as reflected in a reduction of both recognition accuracy and response bias. Event-related potentials revealed a larger late positive potential (LPP, 450 – 700 ms) for angry than for neutral faces during face presentation and, in line with selective rehearsal of remember items, a larger LPP following remember than forget cues. Forget cues generally elicited a larger frontal N2 (280 – 400 ms) than remember cues, in line with the forget instruction eliciting conflict monitoring and inhibition. Selectively following angry faces, a larger cue-evoked P2 (180 – 280 ms) was observed. Notably, forget cues following angry faces elicited a larger late frontal positivity (450 - 700 ms) potentially signaling conflict resolution. Thus, whereas both angry and neutral faces are subject to directed forgetting, on a neural level, different mechanisms underlie the effect. While directed forgetting for neutral faces may be achieved primarily by selective rehearsal, directed forgetting of angry faces involves an additional late frontal positivity, likely reflecting higher cognitive demands imposed by forgetting angry faces.