Implicit weight bias: shared neural substrates for overweight and angry facial expressions revealed by cross-adaptation

The perception of facial expression plays a crucial role in social communication, and it is known to be influenced by various facial cues. Previous studies have reported both positive and negative biases toward overweight individuals. It is unclear whether facial cues, such as facial weight, bias facial expression perception. Combining psychophysics and event-related potential technology, the current study adopted a cross-adaptation paradigm to examine this issue. The psychophysical results of Experiments 1A and 1B revealed a bidirectional cross-adaptation effect between overweight and angry faces. Adapting to overweight faces decreased the likelihood of perceiving ambiguous emotional expressions as angry compared to adapting to normal-weight faces. Likewise, exposure to angry faces subsequently caused normal-weight faces to appear thinner. These findings were corroborated by bidirectional event-related potential results, showing that adaptation to overweight faces relative to normal-weight faces modulated the event-related potential responses of emotionally ambiguous facial expression (Experiment 2A); vice versa, adaptation to angry faces relative to neutral faces modulated the event-related potential responses of ambiguous faces in facial weight (Experiment 2B). Our study provides direct evidence associating overweight faces with facial expression, suggesting at least partly common neural substrates for the perception of overweight and angry faces.

Embracing beauty through leftward movements: An ERP study on metaphorical association between hand actions and aesthetic judgments

In this study, we examined the metaphorical association between aesthetic judgments of faces and horizontal hand movements as well as their cognitive neural mechanisms using a joint categorical response task. In the "aesthetic-action" metaphorical representation situation, participants were asked to classify beautiful/ugly faces by moving the mouse to the left or the right. The results showed that the joint categorization condition "judge beautiful-move mouse left, judge ugly-move mouse right" had a shorter reaction time than the "judge beautiful-move mouse right, judge ugly-move mouse left" condition, which was accompanied by larger amplitudes of the early component N170, EPN, and the late component P300. Combining the behavioral and event-related potentials (ERPs) results, the present study demonstrated a metaphorical association between horizontal hand actions and aesthetic judgments. It suggested that horizontal hand actions can affect the speed of aesthetic judgments by influencing processing fluency, emotional arousal level, categorization motivation, and attentional resources. These findings provide new perspectives to better understand the cognitive process of aesthetic judgments and provide a basis for applying embodied cognition and metaphor theory to the field of aesthetic psychology.

Distrust before first sight? Examining knowledge- and appearance-based effects of trustworthiness on the visual consciousness of faces

The present EEG study with 32 healthy participants investigated whether affective knowledge about a person influences the visual awareness of their face, additionally considering the impact of facial appearance. Faces differing in perceived trustworthiness based on appearance were associated with negative or neutral social information and shown as target stimuli in an attentional blink task. As expected, participants showed enhanced awareness of faces associated with negative compared to neutral social information. On the neurophysiological level, this effect was connected to differences in the time range of the early posterior negativity (EPN)-a component associated with enhanced attention and facilitated processing of emotional stimuli. The findings indicate that the social-affective relevance of a face based on emotional knowledge is accessed during a phase of attentional enhancement for conscious perception and can affect prioritization for awareness. In contrast, no clear evidence for influences of facial trustworthiness during the attentional blink was found.

Deepfake smiles matter less-the psychological and neural impact of presumed AI-generated faces

High-quality AI-generated portraits ("deepfakes") are becoming increasingly prevalent. Understanding the responses they evoke in perceivers is crucial in assessing their societal implications. Here we investigate the impact of the belief that depicted persons are real or deepfakes on psychological and neural measures of human face perception. Using EEG, we tracked participants' (N = 30) brain responses to real faces showing positive, neutral, and negative expressions, after being informed that they are either real or fake. Smiling faces marked as fake appeared less positive, as reflected in expression ratings, and induced slower evaluations. Whereas presumed real smiles elicited canonical emotion effects with differences relative to neutral faces in the P1 and N170 components (markers of early visual perception) and in the EPN component (indicative of reflexive emotional processing), presumed deepfake smiles showed none of these effects. Additionally, only smiles presumed as fake showed enhanced LPP activity compared to neutral faces, suggesting more effortful evaluation. Negative expressions induced typical emotion effects, whether considered real or fake. Our findings demonstrate a dampening effect on perceptual, emotional, and evaluative processing of presumed deepfake smiles, but not angry expressions, adding new specificity to the debate on the societal impact of AI-generated content.

Looking at the upper facial half enlarges the range of holistic face processing

Previous studies suggested that upper and lower facial halves might be involved in the human holistic face processing differently. In this study, we replicated and extended the finding above. In Experiment 1, we used the standard composite-face task to measure holistic face processing when participants made judgements on the upper and lower facial halves separately. Results showed that the composite-face effect was stronger for the upper facial half compared to the lower half. In Experiment 2, we investigated how facial information was integrated when participants focused on different features, using the perceptual field paradigm. Results showed that: (1) more "peripheral faces" were chosen when participants fixated at the eyes than when they fixated at the mouth; (2) less "peripheral faces" were chosen for inverted faces regardless of the fixated features. Findings from both experiments together indicate that more peripheral facial information were integrated when participants focused on the upper facial half, highlighting the significance of focusing on the upper facial half in face processing.

Face-specific negative bias of aesthetic perception in depression: Behavioral and EEG evidence

INTRODUCTION

Symptoms of depression are associated with the dysfunction of neural systems such as the emotion, reward system, and the default mode network. These systems were suggested by the model of neuroaesthetics as key contributions to aesthetic experience, leading to the prediction of atypical aesthetic orientation in depression. Here we investigated the aesthetic characteristics of depression and the corresponding neural underpinnings.

METHODS

Fifty-two (25 depression patients, 27 healthy controls) participants were asked to make aesthetic judgments on faces and landscapes in an electroencephalographic (EEG) experiment.

RESULTS

Our results indicate that relative to the controls, the depression tended to give ugly judgments and refrained from giving beautiful judgments, which was observed only for faces but not for landscapes. We also found that the face-induced component N170 was more negative in the depression group than the control group for ugly and neutral faces. Moreover, the aesthetic evaluation of ugly faces was associated with decreased N200 negativity in the depression group than in the control group, while the evaluation of beautiful faces was associated with decreased brain synchronization at the theta band.

DISCUSSION

These results suggested a face-specific negative aesthetic bias in depression which can help to design and develop aesthetics-oriented schemes in assisting the clinical diagnosis and therapy of depression.

Face identity and facial expression representations with adaptation paradigms: New directions for potential applications

Adaptation and aftereffect are well-known procedures for exploring our neural representation of visual stimuli. It has been reported that they occur in face identity, facial expressions, and low-level visual features. This method has two primary advantages. One is to reveal the common or shared process of faces, that is, the overlapped or discrete representation of face identities or facial expressions. The other is to investigate the coding system or theory of face processing that underlies the ability to recognize faces. This study aims to organize recent research to guide the reader into the field of face adaptation and its aftereffect and to suggest possible future expansions in the use of this paradigm. To achieve this, we reviewed the behavioral short-term aftereffect studies on face identity (i.e., who it is) and facial expressions (i.e., what expressions such as happiness and anger are expressed), and summarized their findings about the neural representation of faces. First, we summarize the basic characteristics of face aftereffects compared to simple visual features to clarify that facial aftereffects occur at a different stage and are not inherited or combinations of low-level visual features. Next, we introduce the norm-based coding hypothesis, which is one of the theories used to represent face identity and facial expressions, and adaptation is a commonly used procedure to examine this. Subsequently, we reviewed studies that applied this paradigm to immature or impaired face recognition (i.e., children and individuals with autism spectrum disorder or prosopagnosia) and examined the relationships between their poor recognition performance and representations. Moreover, we reviewed studies dealing with the representation of non-presented faces and social signals conveyed via faces and discussed that the face adaptation paradigm is also appropriate for these types of examinations. Finally, we summarize the research conducted to date and propose a new direction for the face adaptation paradigm.

Neural specialization to human faces at the age of 7 months

Sensitivity to human faces has been suggested to be an early emerging capacity that promotes social interaction. However, the developmental processes that lead to cortical specialization to faces has remained unclear. The current study investigated both cortical sensitivity and categorical specificity through event-related potentials (ERPs) previously implicated in face processing in 7-month-old infants (N290) and adults (N170). Using a category-specific repetition/adaptation paradigm, cortical specificity to human faces, or control stimuli (cat faces), was operationalized as changes in ERP amplitude between conditions where a face probe was alternated with categorically similar or dissimilar adaptors. In adults, increased N170 for human vs. cat faces and category-specific release from adaptation for face probes alternated with cat adaptors was found. In infants, a larger N290 was found for cat vs. human probes. Category-specific repetition effects were also found in infant N290 and the P1-N290 peak-to-peak response where latter indicated category-specific release from adaptation for human face probes resembling that found in adults. The results suggest cortical specificity to human faces during the first year of life. Encoding of unfamiliar cat stimuli might explain N290 amplification found in infants.

The spatiotemporal characteristics of N170s for faces and words: A meta-analysis study

N170 is a negative event-related potential (ERP) component in response to visual stimuli, such as faces. It remains controversial whether N170 reflects the specific processing of faces or can also be elicited by objects of expertise (e.g., words). In this research, we conducted a meta-analysis for the spatiotemporal characteristics of N170 of face and word stimuli from 24 studies in which both stimuli were presented for each subject. We observed that (1) both face and word stimuli can elicit conspicuous N170s and that there was no difference between the amplitude of face-N170 and word-N170; (2) there is no difference in the latencies between the two N170s; and (3) both N170s are distributed in the occipitotemporal regions but with a reversed hemispheric distribution pattern-face-N170 is more negative in the right than left occipitotemporal regions, while word-N170 is the opposite. These results showed that the face- and word-N170s are qualitatively the same but have different hemispheric lateralization advantages-N170 might be a general neural index of the expertise-dependent object-recognition process in occipitotemporal regions.

Posterior brain sensorimotor recruitment for inhibition of delayed responses in children

Inhibitory control, the ability to suppress irrelevant thoughts or actions, is central to cognitive and social development. Protracted maturation of frontal brain networks has been reported as a major restraint for this ability, yet, young children, when motivated, successfully inhibit delayed responses. A better understanding of the age-dependent neural inhibitory mechanism operating during the awaiting-to-respond window in children may elucidate this conundrum. We recorded ERPs from children and parental adults to a visual-spatial working memory task with delayed responses. Cortical activation elicited during the first 1000 ms of the awaiting-to-respond window showed, as predicted by prior studies, early inhibitory effects in prefrontal ERPs (P200, 160-260 ms) associated with top-down attentional-biasing, and later effects in parietal/occipital ERPs (P300, 270-650 ms) associated with selective inhibition of task-irrelevant stimuli/responses and recurrent memory retrieval. Children successfully inhibited delayed responses and performed with a high level of accuracy (often over 90%), although, the prefrontal P200 displayed reduced amplitude and uniformly delayed peak latency, suggesting low efficacy of top-down attentional-biasing. P300, however, with no significant age-contrasts in latency was markedly elevated in children over the occipital/inferior parietal regions, with effects stronger in younger children. These results provide developmental evidence supporting the sensorimotor recruitment model of visual-spatial working memory relying on the occipital/parietal regions of the early maturing dorsal-visual network. The evidence is in line with the concept of age-dependent variability in the recruitment of cognitive inhibitory networks, complementing the former predominant focus on frontal lobes.

Are You Able to Trust Me? Analysis of the Relationships Between Personality Traits and the Assessment of Attractiveness and Trust

Behavioral and neuroimaging studies show that people trust and collaborate with others based on a quick assessment of the facial appearance. Based on the morphological characteristics of the face, i.e., features, shape, or color, it is possible to determine health, attractiveness, trust, and some personality traits. The study attempts to indicate the features influencing the perception of attractiveness and trust. In order to select individual factors, a model of backward stepwise logistic regression was used, analyzing the results of the psychological tests and the attractiveness and trust survey. Statistical analysis made it possible to select the most important personality traits related to attractiveness and trust assessments.

Mapping the Featural and Holistic Face Processing of Bad and Good Face Recognizers

Individual abilities in face recognition (good versus bad recognizers) were explored by means of event-related potentials (ERPs). The adaptation response profile of the N170 component to whole faces, eyes and mouths was used in order to highlight the crucial role of individual abilities in identity repetition processes for unfamiliar faces. The main point of this study is to underline the importance of characterizing the performance (bad or good) of the participants and to show that behaviorally selected groups might reveal neural differences. Good recognizers showed selective right hemisphere N170 repetition effects for whole faces and not for features. On the contrary, bad recognizers showed a general repetition effect not specifically related to faces and more pronounced processing for features. These findings suggest a different contribution of holistic and featural analysis in bad and good performers. In conclusion, we propose that the N170 might be used as a tool to tease apart face encoding processes as a function of individual differences.

EPOC outside the shield: comparing the performance of a consumer-grade EEG device in shielded and unshielded environments

Low-cost, portable electroencephalography (EEG) devices have become commercially available in the last 10 years. One such system, Emotiv's EPOC, has been modified to allow event-related potential (ERP) research. Although the EPOC has been shown to provide data comparable to research-grade equipment and has been used in real-world settings, how EPOC performs without the electrical shielding, commonly used in research-grade laboratories, is yet to be systematically tested. In the current article we address this gap by conducting a simple EEG experiment in shielded and unshielded contexts. Participants (n = 13, mean age = 23.2 years, SD = 7.9) monitored the presentation of human versus wristwatch faces, responding whether the images were inverted or not. This method elicited the face-sensitive N170 ERP. In both shielded and unshielded contexts, the N170 amplitude was larger when participants viewed human faces and peaked later when a human face was inverted. More importantly, Bayesian analysis showed no difference in the N170 measured in the shielded and unshielded contexts. Further, the signal recorded in both contexts was highly correlated. The EPOC appears to reliably record EEG signals without a purpose-built electrically-shielded room.

Effects of Minimal Grouping On Implicit Prejudice, Infrahumanization, and Neural Processing Despite Orthogonal Social Categorizations

Racial prejudice is a pervasive and pernicious form of intergroup bias. However, a mounting number of studies show that re-categorization-even into minimal groups-can overcome the typical consequences of racial and other group classifications. We tested the effects of minimal grouping on implicit prejudice and infrahumanization using a paradigm in which race was orthogonal to group membership. This allowed us to examine whether knowledge of group membership overrides obvious category differences. We found that participants infrahumanized and showed implicit bias toward the minimal out-group, despite the crosscutting presence of race, and in fact did not show any of the usual implicit racial bias. In addition, Event-Related Potentials (ERPs) showed an early race effect followed by distinct reactions on the basis of group as processing continued. This is evidence that arbitrary social classifications can engender in-group preference even in the presence of orthogonal, visually salient categorizations.

Neural responses to dynamic adaptation reveal the dissociation between the processing of the shape of contours and textures

Shape-adaptation studies show that surround textures can inhibit the processing of contours. Using event-related potentials (ERP), we examined the time-course of neural processes involved in contour-shape and texture-shape processing following adaptation to contours and textures. Contours were made of Gabor strings whose orientations were either tangential or orthogonal to the contour path, while textures were made of a series of contours arranged in parallel. We focused on two ERP components -P1, related to low-level visual processes and N1, broadly indicative of mid-level vision- and, on ERP difference waves (no-adaptor minus with-adaptor) to isolate the effects of adaptation, which are fundamentally distinct from individual processes driving P1 and N1 components. We found that in the absence of adaptation, the N1 component for contour-tests peaked later and increased in amplitude compared to the N1 for texture-tests. Following adaptation, the ERP difference wave for contour-tests revealed an early and a late component that were differentially affected by the presence of surround texture, but critically not by its orientation. For texture-tests, the early component was of opposite polarity for contours compared to texture adaptors. From the temporal sequence of ERP modulations, we conclude that texture processing begins before contour processing and encompasses the stages of perceptual processing reflected in both the low-level P1 and the mid-level N1 vision-related components. Our study provides novel evidence on the nature of separable and temporally distinct texture and contour processing mechanisms, shown in two difference wave components, that highlights the multi-faceted nature of dynamic adaptation to shape when presented in isolation and in context.

Comparing electrophysiological correlates of judgment of learning and feeling of knowing during face-name recognition

We investigated the event-related potential (ERP) correlates of two metacognitive judgments, namely judgment of learning (JOL) and feeling of knowing (FOK) induced by a face-name recognition (FNR) task in 60 participants. The FNR produced N170 and P100 components at posterior, and an N100 component at anterior electrodes. Posterior P200, anterior N200 components were recorded during JOL and FOK judgments. Our data showed that ERP correlates of JOL and FOK emerge as rapidly as 200 ms following stimulus presentation, and these two metacognitive judgments are based on both perceptual fluency and conflict processes. However, these ERP components affected by the degree of JOL and FOK judgments. Thus, we concluded that even though JOL and FOK judgments produced similar ERP wave forms temporal dynamics of these two judgments are different. Also, our results support the hypothesis that metacognitive judgments are linked to distributed neural substrates rather than strictly to frontal lobe function.

The recovery speed of category sensitive N170 responses to faces and Chinese characters

Neural selectivity of N170 responses is important for understanding face, word, and object processing in the brain. However, the recovery times of neural selective responses remain unclear. In the present study, we used an adaptation paradigm to test the recovery speed of N170 responses to faces and Chinese characters. The findings revealed that recovery of N170 responses elicited by faces occurred between 1400 and 1800 ms after stimulus onset, whereas those elicited by Chinese characters occurred between 600 and 800 ms. These results demonstrate that N170 responses involved in the processing of faces and Chinese characters exhibit category sensitive recovery speeds.

The peripheral preview effect with faces: Combined EEG and eye-tracking suggests multiple stages of trans-saccadic predictive and non-predictive processing

The world appears stable despite saccadic eye-movements. One possible explanation for this phenomenon is that the visual system predicts upcoming input across saccadic eye-movements based on peripheral preview of the saccadic target. We tested this idea using concurrent electroencephalography (EEG) and eye-tracking. Participants made cued saccades to peripheral upright or inverted face stimuli that changed orientation (invalid preview) or maintained orientation (valid preview) while the saccade was completed. Experiment 1 demonstrated better discrimination performance and a reduced fixation-locked N170 component (fN170) with valid than with invalid preview, demonstrating integration of pre- and post-saccadic information. Moreover, the early fixation-related potentials (FRP) showed a preview face inversion effect suggesting that some pre-saccadic input was represented in the brain until around 170 ms post fixation-onset. Experiment 2 replicated Experiment 1 and manipulated the proportion of valid and invalid trials to test whether the preview effect reflects context-based prediction across trials. A whole-scalp Bayes factor analysis showed that this manipulation did not alter the fN170 preview effect but did influence the face inversion effect before the saccade. The pre-saccadic inversion effect declined earlier in the mostly invalid block than in the mostly valid block, which is consistent with the notion of pre-saccadic expectations. In addition, in both studies, we found strong evidence for an interaction between the pre-saccadic preview stimulus and the post-saccadic target as early as 50 ms (Experiment 2) or 90 ms (Experiment 1) into the new fixation. These findings suggest that visual stability may involve three temporal stages: prediction about the saccadic target, integration of pre-saccadic and post-saccadic information at around 50-90 ms post fixation onset, and post-saccadic facilitation of rapid categorization.

Left-Side Bias Is Observed in Sequential Matching Paradigm for Face Processing

The left-side bias refers to how a chimeric face is created from the left side of a face (from the viewer’s perspective) and its mirror image are considered more similar to the original face than a chimeric face created from the right side of the same face and its mirror image. Previous studies investigated the left-side bias by using the chimeric stimuli task, where the original face and chimeric face were presented simultaneously. However, it remains unclear whether left-side bias effect is observed when the original face and chimeric face are presented sequentially. We completed two experiments using the sequential matching paradigm to investigate this issue. The results from both Experiment 1 and 2 showed that participants judged the identical proportion of the left chimeric face and original face was significantly higher than that of the right chimeric face and original face, which implies that the left-side bias effect can be observed in the sequential matching paradigm for face processing.

Event-related potential (ERP) correlates of face processing in verbal children with autism spectrum disorders (ASD) and their first-degree relatives: a family study

Background

Inherited abnormalities of perception, recognition, and attention to faces have been implicated in the etiology of autism spectrum disorders (ASD) including abnormal components of event-related brain potentials (ERP) elicited by faces.

Methods

We examined familial aggregation of face processing ERP abnormalities previously implicated in ASD in 49 verbal individuals with ASD, 36 unaffected siblings (US), 18 unaffected fathers (UF), and 53 unrelated controls (UC). The ASD, US, and UC groups ranged in age from 12 to 21 years, the UF group ranged in age from 30 to 56 years. ERP responses to images of upright and inverted faces and houses were analyzed under disparate EEG reference schemes.

Results

Face-sensitive features of N170 and P1 were readily observed in all groups. Differences between ASD and control groups depended upon the EEG reference scheme. Notably, the superiority of face over object for N170 latency was attenuated in ASD subjects, but not their relatives; this occurred exclusively with the average reference. The difference in N170 amplitude between inverted and upright faces was reduced in both ASD and US groups relative to UC, but this effect was significant only with the vertex reference. Furthermore, similar group differences were observed for both inverted faces and inverted houses, suggesting a lack of face specificity for the attenuation of the N170 inversion effect in ASD.

Conclusion

The present findings refine understanding of face processing ERPs in ASD. These data provide only modest evidence for highly-selective ASD-sensitive ERP features, and underscore the sensitivity of these biomarkers to ERP reference scheme. These schemes have varied across published studies and must be accounted for in future studies of the relationship between these commonly acquired ERP characteristics, genotype, and ASD.

Sex Differences in Categorical Adaptation for Faces and Chinese Characters during Early Perceptual Processing

Previous event-related potential studies support sex differences in the N170 response during face and word processing; however, it remains unclear whether N170 categorical adaptation for faces and words is different between women and men. Using an adaptation paradigm, in which an adaptor and subsequent test stimulus are presented during each trial, the present study investigated N170 categorical adaptation for faces and Chinese characters in both women and men. The results demonstrated that the N170 amplitude elicited by test stimuli in within-category condition was lower than in control category condition, and this was observed during both face and Chinese character processing in women and men. In addition, we found that men have greater N170 categorical adaptation for face and word processing than women. There was also a significant correlation between N170 categorical adaptation indices for face and Chinese character processing in men, which did not occur in women. These findings suggest that men and women process repeated faces or words differently.

Fear boosts the early neural coding of faces

The rapid extraction of facial identity and emotional expressions is critical for adapted social interactions. These biologically relevant abilities have been associated with early neural responses on the face sensitive N170 component. However, whether all facial expressions uniformly modulate the N170, and whether this effect occurs only when emotion categorization is task-relevant, is still unclear. To clarify this issue, we recorded high-resolution electrophysiological signals while 22 observers perceived the six basic expressions plus neutral. We used a repetition suppression paradigm, with an adaptor followed by a target face displaying the same identity and expression (trials of interest). We also included catch trials to which participants had to react, by varying identity (identity-task), expression (expression-task) or both (dual-task) on the target face. We extracted single-trial Repetition Suppression (stRS) responses using a data-driven spatiotemporal approach with a robust hierarchical linear model to isolate adaptation effects on the trials of interest. Regardless of the task, fear was the only expression modulating the N170, eliciting the strongest stRS responses. This observation was corroborated by distinct behavioral performance during the catch trials for this facial expression. Altogether, our data reinforce the view that fear elicits distinct neural processes in the brain, enhancing attention and facilitating the early coding of faces.

3D faces are recognized more accurately and faster than 2D faces, but with similar inversion effects

Recognition of faces typically occurs via holistic processing where individual features are combined to provide an overall facial representation. However, when faces are inverted, there is greater reliance on featural processing where faces are recognized based on their individual features. These findings are based on a substantial number of studies using 2-dimensional (2D) faces and it is unknown whether these results can be extended to 3-dimensional (3D) faces, which have more depth information that is absent in the typical 2D stimuli used in face recognition literature. The current study used the face inversion paradigm as a means to investigate how holistic and featural processing are differentially influenced by 2D and 3D faces. Twenty-five participants completed a delayed face-matching task consisting of upright and inverted faces that were presented as both 2D and 3D stereoscopic images. Recognition accuracy was significantly higher for 3D upright faces compared to 2D upright faces, providing support that the enriched visual information in 3D stereoscopic images facilitates holistic processing that is essential for the recognition of upright faces. Typical face inversion effects were also obtained, regardless of whether the faces were presented in 2D or 3D. Moreover, recognition performances for 2D inverted and 3D inverted faces did not differ. Taken together, these results demonstrated that 3D stereoscopic effects influence face recognition during holistic processing but not during featural processing. Our findings therefore provide a novel perspective that furthers our understanding of face recognition mechanisms, shedding light on how the integration of stereoscopic information in 3D faces influences face recognition processes.

Emotional cue validity effects: The role of neurocognitive responses to emotion

The beneficial effect of valid compared to invalid cues on attention performance is a basic attentional mechanism, but the impact of emotional content on cue validity is poorly understood. We tested whether the effect of cue validity on attention performance differed when cues were angry, happy, or neutral faces. Moreover, we used scalp-recorded event-related potentials (ERPs) reflecting the capture of early visual attention (P1, N170) to test whether effects were strengthened when neurocognitive responses to angry or happy cues were enhanced (larger P1 and N170 amplitudes). Twenty-five participants completed a modified flanker task using emotional face cues to measure the effects of emotion on conflict interference. Attention performance was enhanced following valid versus invalid cues, but effects did not differ by emotion cue type. However, for participants showing relatively larger N170 amplitudes to angry face cues, attention performance was specifically disrupted on those trials. Conversely, participants with relatively larger N170 amplitudes to happy face cues showed facilitated performance across all valid trials. These findings suggest that individual neurocognitive sensitivities to emotion predict the impact of emotional content on the basic attentional phenomenon of cue validity.

The Cognitive and Neural Basis of Developmental Prosopagnosia

Developmental prosopagnosia (DP) is a severe impairment of visual face recognition in the absence of any apparent brain damage. The factors responsible for DP have not yet been fully identified. This article provides a selective review of recent studies investigating cognitive and neural processes that may contribute to the face recognition deficits in DP, focusing primarily on event-related brain potential (ERP) measures of face perception and recognition. Studies that measured the face-sensitive N170 component as a marker of perceptual face processing have shown that the perceptual discrimination between faces and non-face objects is intact in DP. Other N170 studies suggest that faces are not represented in the typical fashion in DP. Individuals with DP appear to have specific difficulties in processing spatial and contrast deviations from canonical upright visual–perceptual face templates. The rapid detection of emotional facial expressions appears to be unaffected in DP. ERP studies of the activation of visual memory for individual faces and of the explicit identification of particular individuals have revealed differences between DPs and controls in the timing of these processes and in the links between visual face memory and explicit face recognition. These observations suggest that the speed and efficiency of information propagation through the cortical face network is altered in DP. The nature of the perceptual impairments in DP suggests that atypical visual experience with the eye region of faces over development may be an important contributing factor to DP.

Differences in the dynamics of affective and cognitive processing - An ERP study

A controversy in emotion research concerns the question of whether affective or cognitive primacy are evident in processing affective stimuli and the factors contributing to each alternative. Using electrophysiological recordings in an adapted visual oddball paradigm allowed tracking the dynamics of affective and cognitive effects. Stimuli consisted of face pictures displaying affective expressions with rare oddballs differing from frequent stimuli in either affective expression, structure (while frequent stimuli were shown frontally these deviants were turned sideways) or they differed on both dimensions, i.e. in affective expression and structure. Results revealed a defined sequence of differences in ERP amplitudes: For stimuli deviating in their affective expression only, P1 modulations ~100ms were evident, while affective differences of structure deviants were not evident before the N170 time window. All three types of deviants differed in P300 amplitudes, indicating integration of affective and structural information. These results encompass evidence for both, cognitive and affective primacy depending on stimulus properties. Specifically affective primacy is only visible when the respective facial features can be extracted with ease. When structural differences make face processing harder, however, cognitive primacy is brought forward.

Dissociating Attention Effects from Categorical Perception with ERP Functional Microstates

When faces appear in our visual environment we naturally attend to them, possibly to the detriment of other visual information. Evidence from behavioural studies suggests that faces capture attention because they are more salient than other types of visual stimuli, reflecting a category-dependent modulation of attention. By contrast, neuroimaging data has led to a domain-specific account of face perception that rules out the direct contribution of attention, suggesting a dedicated neural network for face perception. Here we sought to dissociate effects of attention from categorical perception using Event Related Potentials. Participants viewed physically matched face and butterfly images, with each category acting as a target stimulus during different blocks in an oddball paradigm. Using a data-driven approach based on functional microstates, we show that the locus of endogenous attention effects with ERPs occurs in the N1 time range. Earlier categorical effects were also found around the level of the P1, reflecting either an exogenous increase in attention towards face stimuli, or a putative face-selective measure. Both category and attention effects were dissociable from one another hinting at the role that faces may play in early capturing of attention before top-down control of attention is observed. Our data support the conclusion that certain object categories, in this experiment, faces, may capture attention before top-down voluntary control of attention is initiated.

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude.

The ANK3 gene and facial affect processing: An ERP study

ANK3 is one of the most promising candidate genes for bipolar disorder (BD). A polymorphism (rs10994336) within the ANK3 gene has been associated with BD in at least three genome-wide association studies of BD [McGuffin et al., 2003; Kieseppä, 2004; Edvardsen et al., 2008]. Because facial affect processing is disrupted in patients with BD, the current study aimed to explore whether the BD risk alleles are associated with the N170, an early event-related potential (ERP) component related to facial affect processing. We collected data from two independent samples of healthy individuals (Ns = 83 and 82, respectively) to test the association between rs10994336 and an early event-related potential (ERP) component (N170) that is sensitive to facial affect processing. Repeated-measures analysis of covariance in both samples consistently revealed significant main effects of rs10994336 genotype (Sample I: F (1, 72) = 7.24, P = 0.009; Sample II: F (1, 69) = 11.81, P = 0.001), but no significant interaction of genotype × electrodes (Ps > 0.05) or genotype × emotional conditions (Ps > 0.05). These results suggested that rs10994336 was linked to early ERP component reflecting facial structural encoding during facial affect processing. These results shed new light on the brain mechanism of this risk SNP and associated disorders such as BD. © 2016 Wiley Periodicals, Inc.

Task-irrelevant fear enhances amygdala-FFG inhibition and decreases subsequent face processing

Facial threat is associated with changes in limbic activity as well as modifications in the cortical face-related N170. It remains unclear if task-irrelevant threat modulates the response to a subsequent facial stimulus, and whether the amygdala's role in early threat perception is independent and direct, or modulatory. In 19 participants, crowds of emotional faces were followed by target faces and a rating task while simultaneous EEG-fMRI were recorded. In addition to conventional analyses, fMRI-informed EEG analyses and fMRI dynamic causal modeling (DCM) were performed. Fearful crowds reduced EEG N170 target face amplitudes and increased responses in a fMRI network comprising insula, amygdala and inferior frontal cortex. Multimodal analyses showed that amygdala response was present ∼60 ms before the right fusiform gyrus-derived N170. DCM indicated inhibitory connections from amygdala to fusiform gyrus, strengthened when fearful crowds preceded a target face. Results demonstrated the suppressing influence of task-irrelevant fearful crowds on subsequent face processing. The amygdala may be sensitive to task-irrelevant fearful crowds and subsequently strengthen its inhibitory influence on face-responsive fusiform N170 generators. This provides spatiotemporal evidence for a feedback mechanism of the amygdala by narrowing attention in order to focus on potential threats.

Electrophysiological evidence of inhibited orthographic regularity effect on the recognition of real Chinese characters

Orthographic regularity is important for processing Chinese characters. However, the issues how orthographic regularity influences the visual recognition of real Chinese characters and whether common processes related to the potential effect exist between successive (SUCC) and concurrent (CONC) conditions with asynchronous presentation of S1 and S2 are still unclear. In the current study, event-related potential (ERP) technique was adopted to investigate electrophysiological correlates of the orthographic regularity effect. Behaviorally, we found fewer errors and shorter response times for SUCC and CONC conditions compared to simultaneous (SIM) condition with synchronous presentation and disappearance of S1 and S2, which demonstrates similarities between SUCC and CONC and their differences from SIM. We found bilaterally smaller N170 responses for real Chinese characters preceded by false characters compared to real characters, demonstrating that orthographic regularity may inhibit the recognition of real Chinese characters. Additionally, the inhibition effect was present in SUCC and CONC rather than SIM, which shows that smaller N170 responses may have been due to asynchronous presentations of S1 and S2 and common inhibition processes in the SUCC and CONC conditions.

N170 Changes Show Identifiable Chinese Characters Compete Primarily with Faces Rather than Houses

Character processing is a crucial cognitive skill that is highly emphasized and industriously cultivated in contemporary society. In the present study, using a competition paradigm, we examined the electrophysiological correlates of different relationships between Chinese characters and faces and between Chinese characters and houses during early visual processing. We observed that identifiable Chinese characters compete primarily with faces rather than houses at an early visual processing stage, with a significantly reduced N170 for faces but not for houses, when they were viewed concurrently with identifiable characters relative to when they were viewed concurrently with unidentifiable characters. Consistent with our previous study, there was a significant increase in N170 after characters have been learned, indicating a modulatory effect of Chinese character identification level on N170 amplitude. Furthermore, we found an enlarged N170 in response to faces compared to houses, indicating that the neural mechanisms for processing faces and houses are different at an early visual processing stage.

Time course of facial emotion processing in women with borderline personality disorder: an ERP study

BACKGROUND

Borderline personality disorder (BPD) is characterized by a negative perception of others. Previous studies have revealed deficits and biases in facial emotion recognition. This study investigates the behavioural and electrophysiological correlates underlying facial emotion processing in individuals with BPD.

METHODS

The present study was conducted between July 2012 and May 2014. In an emotion classification task, unmedicated female patients with BPD as well as healthy women had to classify faces displaying blends of anger and happiness while the electroencephalogram was recorded. We analyzed visual event-related potentials (ERPs) reflecting early (P100), structural (N170) and categorical (P300) facial processing in addition to behavioural responses.

RESULTS

We included 36 women with BPD and 29 controls in our analysis. Patients with BPD were more likely than controls to classify predominantly happy faces as angry. Independent of facial emotion, women with BPD showed enhanced early occipital P100 amplitudes. Additionally, temporo-occipital N170 amplitudes were reduced at right hemispherical electrode sites. Centroparietal P300 amplitudes were reduced particularly for predominantly happy faces and increased for highly angry faces in women with BPD, whereas in healthy volunteers this component was modulated by both angry and happy facial affect.

LIMITATIONS

Our sample included only women, and no clinical control group was investigated.

CONCLUSION

Our findings suggest reduced thresholds for facial anger and deficits in the discrimination of facial happiness in individuals with BPD. This biased perception is associated with alterations in very early visual as well as deficient structural and categorical processing of faces. The current data could help to explain the negative perception of others that may be related to the patients' impairments in interpersonal functioning.

Adaptation Duration Dissociates Category-, Image-, and Person-Specific Processes on Face-Evoked Event-Related Potentials

Several studies demonstrated that face perception is biased by the prior presentation of another face, a phenomenon termed as face-related after-effect (FAE). FAE is linked to a neural signal-reduction at occipito-temporal areas and it can be observed in the amplitude modulation of the early event-related potential (ERP) components. Recently, macaque single-cell recording studies suggested that manipulating the duration of the adaptor makes the selective adaptation of different visual motion processing steps possible. To date, however, only a few studies tested the effects of adaptor duration on the electrophysiological correlates of human face processing directly. The goal of the current study was to test the effect of adaptor duration on the image-, identity-, and generic category-specific face processing steps. To this end, in a two-alternative forced choice familiarity decision task we used five adaptor durations (ranging from 200-5000 ms) and four adaptor categories: adaptor and test were identical images-Repetition Suppression (RS); adaptor and test were different images of the Same Identity (SameID); adaptor and test images depicted Different Identities (DiffID); the adaptor was a Fourier phase-randomized image (No). Behaviorally, a strong priming effect was observed in both accuracy and response times for RS compared with both DiffID and No. The electrophysiological results suggest that rapid adaptation leads to a category-specific modulation of P100, N170, and N250. In addition, both identity and image-specific processes affected the N250 component during rapid adaptation. On the other hand, prolonged (5000 ms) adaptation enhanced, and extended category-specific adaptation processes over all tested ERP components. Additionally, prolonged adaptation led to the emergence of image-, and identity-specific modulations on the N170 and P2 components as well. In other words, there was a clear dissociation among category, identity-, and image-specific processing steps in the case of longer (3500 and 5000 ms) but not for shorter durations (< 3500 ms), reflected in the gradual reduction of N170 and enhancement of P2 in the No, DiffID, SameID, and RS conditions. Our findings imply that by manipulating adaptation duration one can dissociate the various steps of human face processing, reflected in the ERP response.

Eyeglasses elicit effects similar to face-like perceptual expertise: evidence from the N170 response

Studies of event-related potentials show that the specific N170 response has become a stable electrophysiological hallmark of objects related to expertise in early perceptual processing. In the present study, we investigated whether eyeglasses can elicit N170 effects similar to those elicited by objects of expertise. Our results showed that the N170 response elicited by eyeglasses was larger than the response elicited by objects that do not generate perceptual expertise (e.g., houses). Importantly, we found that eyeglasses could produce a within-category N170 adaptation effect, similar to that produced in response to objects of expertise (e.g., faces). Our results have revealed for the first time that with a large amount of experience, eyeglasses could evoke the face-like N170 response, which suggested that eyeglasses may become an object of perceptual expertise to some human observers.

Perceptual face processing in developmental prosopagnosia is not sensitive to the canonical location of face parts

Individuals with developmental prosopagnosia (DP) are strongly impaired in recognizing faces, but it is controversial whether this deficit is linked to atypical visual-perceptual face processing mechanisms. Previous behavioural studies have suggested that face perception in DP might be less sensitive to the canonical spatial configuration of face parts in upright faces. To test this prediction, we recorded event-related brain potentials (ERPs) to intact upright faces and to faces with spatially scrambled parts (eyes, nose, and mouth) in a group of ten participants with DP and a group of ten age-matched control participants with normal face recognition abilities. The face-sensitive N170 component and the vertex positive potential (VPP) were both enhanced and delayed for scrambled as compared to intact faces in the control group. In contrast, N170 and VPP amplitude enhancements to scrambled faces were absent in the DP group. For control participants, the N170 to scrambled faces was also sensitive to feature locations, with larger and delayed N170 components contralateral to the side where all features appeared in a non-canonical position. No such differences were present in the DP group. These findings suggest that spatial templates of the prototypical feature locations within an upright face are selectively impaired in DP.