Is your own face more than a highly familiar face?

Investigating the impact of motion visual synchrony on self face recognition using real time morphing

Face recognition is a crucial aspect of self-image and social interactions. Previous studies have focused on static images to explore the boundary of self-face recognition. Our research, however, investigates the dynamics of face recognition in contexts involving motor-visual synchrony. We first validated our morphing face metrics for self-face recognition. We then conducted an experiment using state-of-the-art video processing techniques for real-time face identity morphing during facial movement. We examined self-face recognition boundaries under three conditions: synchronous, asynchronous, and static facial movements. Our findings revealed that participants recognized a narrower self-face boundary with moving facial images compared to static ones, with no significant differences between synchronous and asynchronous movements. The direction of morphing consistently biased the recognized self-face boundary. These results suggest that while motor information of the face is vital for self-face recognition, it does not rely on movement synchronization, and the sense of agency over facial movements does not affect facial identity judgment. Our methodology offers a new approach to exploring the 'self-face boundary in action', allowing for an independent examination of motion and identity.

P1, N170, and N250 Event-related Potential Components Reflect Temporal Perception Processing in Face and Body Personal Identification

Human faces and bodies represent various socially important signals. Although adults encounter numerous new people in daily life, they can recognize hundreds to thousands of different individuals. However, the neural mechanisms that differentiate one person from another person are unclear. This study aimed to clarify the temporal dynamics of the cognitive processes of face and body personal identification using face-sensitive ERP components (P1, N170, and N250). The present study performed three blocks (face-face, face-body, and body-body) of different ERP adaptation paradigms. Furthermore, in the above three blocks, ERP components were used to compare brain biomarkers under three conditions (same person, different person of the same sex, and different person of the opposite sex). The results showed that the P1 amplitude for the face-face block was significantly greater than that for the body-body block, that the N170 amplitude for a different person of the same sex condition was greater than that for the same person condition in the right hemisphere only, and that the N250 amplitude gradually increased as the degree of face and body sex-social categorization grew closer (i.e., same person condition > different person of the same sex condition > different person of the opposite sex condition). These results suggest that early processing of the face and body processes the face and body separately and that structural encoding and personal identification of the face and body process the face and body collaboratively.

This is me! Neural correlates of self-recognition in 6- to 8-month-old infants

Historically, evidence of self-recognition in development has been associated with the "rouge test"; however, this has been often criticized for providing a reductionist picture of self-conscious behavior. With two event-related potential (ERP) experiments, this study investigated the origin of self-recognition. Six- to eight-month-old infants (42 males and 35 females, predominately White, tested in the UK in 2022-2023) were presented with images of their face, another peer's face, and their mother's face (N = 38, Exp.1), and images of their own face morphed into another peer's face (N = 39, Exp.2). Results showed an enhanced P100 in infants' ERP response to their own face compared to others' faces (Exp.1 only), suggesting the presence of an enhanced attentional mechanism to one own's face as early as 6 months.

The Self-reference Effect Can Modulate Language Syntactic Processing Even Without Explicit Awareness: An Electroencephalography Study

Although it is well established that self-related information can rapidly capture our attention and bias cognitive functioning, whether this self-bias can affect language processing remains largely unknown. In addition, there is an ongoing debate as to the functional independence of language processes, notably regarding the syntactic domain. Hence, this study investigated the influence of self-related content on syntactic speech processing. Participants listened to sentences that could contain morphosyntactic anomalies while the masked face identity (self, friend, or unknown faces) was presented for 16 msec preceding the critical word. The language-related ERP components (left anterior negativity [LAN] and P600) appeared for all identity conditions. However, the largest LAN effect followed by a reduced P600 effect was observed for self-faces, whereas a larger LAN with no reduction of the P600 was found for friend faces compared with unknown faces. These data suggest that both early and late syntactic processes can be modulated by self-related content. In addition, alpha power was more suppressed over the left inferior frontal gyrus only when self-faces appeared before the critical word. This may reflect higher semantic demands concomitant to early syntactic operations (around 150-550 msec). Our data also provide further evidence of self-specific response, as reflected by the N250 component. Collectively, our results suggest that identity-related information is rapidly decoded from facial stimuli and may impact core linguistic processes, supporting an interactive view of syntactic processing. This study provides evidence that the self-reference effect can be extended to syntactic processing.

Subjectively salient faces differ from emotional faces: ERP evidence

The self-face is processed differently than emotional faces. A question arises whether other highly familiar and subjectively significant non-self faces (e.g. partner's face) are also differentiated from emotional faces. The aim of this event-related potential (ERP) study was to investigate the neural correlates of personally-relevant faces (the self and a close-other's) as well as emotionally positive (happy) and neutral faces. Participants were tasked with the simple detection of faces. Amplitudes of N170 were more negative in the right than in the left hemisphere and were not modulated by type of face. A similar pattern of N2 and P3 results for the self-face and close-other's face was observed: they were associated with decreased N2 and increased P3 relative to happy and neutral faces. However, the self-face was preferentially processed also when compared to a close-other's face as revealed by lower N2 and higher P3 amplitudes. Nonparametric cluster-based permutation tests showed an analogous pattern of results: significant clusters for the self-face compared with all other faces (close-other's, happy, neutral) and for close-other's face compared to happy and neutral faces. In summary, the self-face prioritization was observed, as indicated by significant differences between one's own face and all other faces. Crucially, both types of personally-relevant faces differed from happy faces. These findings point to the pivotal role of subjective evaluation of the saliency factor.

Transcranial alternating current stimulation ameliorates emotional attention through neural oscillations modulation

Background

Numerous clinical reports have suggested that psychopathy like schizophrenia, anxiety and depression is accompanied by early attentional abnormalities in emotional processing. Recently, the efficacy of transcranial alternating current stimulation (tACS) in changing emotional functioning has been repeatedly observed and demonstrated a causal relationship between endogenous oscillations and emotional processing.

Aims

Up to now, tACS effects on emotional attention have not yet been tested. To assess such ability, we delivered active-tACS at individual alpha frequency (IAF), 10 Hz or sham-tACS for 7 consecutive days in the bilaterally dorsolateral prefrontal cortex (dlPFC) to totally 79 healthy participants.

Results

IAF-tACS group showed significant alpha entrainment at-rest, especially in open state around stimulation area and showed an obvious advantage compared to 10 Hz-tACS. Event-related potential revealed a significant larger P200 amplitude after active-tACS and IAF group showed wider range of emotions than 10 Hz-tACS, indicating the attentional improvement in facial emotion processing. A notable positive correlation between alpha power and P200 amplitude provided an electrophysiological interpretation regarding the role of tACS in emotional attention modulation instead of somatosensory effects.

Conclusion

These results support a seminal outcome for the effect of IAF-tACS on emotional attention modulation, demonstrating a feasible and individual-specific therapy for neuropsychiatric disorders related to emotion processing, especially regarding oscillatory disturbances.

The neural dynamics of familiarity-dependent face identity representation

Recognizing a face as belonging to a given identity is essential in our everyday life. Clearly, the correct identification of a face is only possible for familiar people, but 'familiarity' covers a wide range-from people we see every day to those we barely know. Although several studies have shown that the processing of familiar and unfamiliar faces is substantially different, little is known about how the degree of familiarity affects the neural dynamics of face identity processing. Here, we report the results of a multivariate EEG analysis, examining the representational dynamics of face identity across several familiarity levels. Participants viewed highly variable face images of 20 identities, including the participants' own face, personally familiar (PF), celebrity and unfamiliar faces. Linear discriminant classifiers were trained and tested on EEG patterns to discriminate pairs of identities of the same familiarity level. Time-resolved classification revealed that the neural representations of identity discrimination emerge around 100 ms post-stimulus onset, relatively independently of familiarity level. In contrast, identity decoding between 200 and 400 ms is determined to a large extent by familiarity: it can be recovered with higher accuracy and for a longer duration in the case of more familiar faces. In addition, we found no increased discriminability for faces of PF persons compared to those of highly familiar celebrities. One's own face benefits from processing advantages only in a relatively late time-window. Our findings provide new insights into how the brain represents face identity with various degrees of familiarity and show that the degree of familiarity modulates the available identity-specific information at a relatively early time window.

Posterior theta activity reveals an early signal of self-face recognition

Self-related visual information, especially one's own face and name, are processed in a specific, prioritized way. However, the spatio-temporal brain dynamics of self-prioritization have remained elusive. Moreover, it has been unclear whether this prioritization is an effect of enhancement and amplification, or rather a facilitating automatization of processing self-referential information. In this EEG study, 25 married women (who changed their surnames after marriage, so that their past and present surnames could be used as stimuli) performed a detection task with faces and names from five categories: self, self from the past, friend, famous, and unknown person. The aim was to determine the temporal and spatial characteristics of early electrophysiological markers of self-referential processing. We report results of event-related component (ERP) and time-frequency analyses. In the ERPs, the earliest self-relevance effect was displayed only 300 ms after stimulus onset in the midfrontal N2, and later in the parietal P3b, independently of the stimulus type. No self-relevance effect was found on the N170 component. However, local theta power at the occipito-temporal (visual) areas and inter-regional theta phase coherence between the visual and midfrontal areas showed that self-relevance differentiation of faces began already about 100-300 ms after stimulus onset. No such early effects were found for names. The results are discussed in terms of the time-course, functional localization, stimulus-specificity, and automatization of self-prioritization.

Developing familiarity during the first eight months of knowing a person: A longitudinal EEG study on face and identity learning

It is well-established that familiar and unfamiliar faces are processed differently, but surprisingly little is known about how familiarity builds up over time and how novel faces gradually become represented in the brain. Here, we used event-related brain potentials (ERPs) in a pre-registered, longitudinal study to examine the neural processes accompanying face and identity learning during the first eight months of knowing a person. Specifically, we examined how increasing real-life familiarity affects visual recognition (N250 Familiarity Effect) and the integration of person-related knowledge (Sustained Familiarity Effect, SFE). Sixteen first-year undergraduates were tested in three sessions, approximately one, five, and eight months after the start of the academic year, with highly variable "ambient" images of a new friend they had met at university and of an unfamiliar person. We observed clear ERP familiarity effects for the new friend after one month of familiarity. While there was an increase in the N250 effect over the course of the study, no change in the SFE was observed. These results suggest that visual face representations develop faster relative to the integration of identity-specific knowledge.

Laterality and hemispheric specialization of self-face recognition

Inspired by the pioneering work of Eran Zaidel beginning in the early 1970's on the role of the two cerebral hemispheres of the human brain in self-related cognition, we review research on self-face recognition from a laterality perspective. The self-face is an important proxy of the self, and self-face recognition has been used as an indicator of self-awareness more broadly. Over the last half century, behavioral and neurological data, along with over two decades of neuroimaging research evidence have accumulated on this topic, generally concluding a right-hemisphere dominance for self-face recognition. In this review, we briefly revisit the pioneering roots of this work by Sperry, Zaidel & Zaidel, and focus on the important body of neuroimaging literature on self-face recognition it has inspired. We conclude with a brief discussion of current models of self-related processing and future directions for research in this area.

Variation in self and familiar facial recognition in bipolar disorder patients at different clinical stages

Previous studies suggest a close relationship between self-disorders and schizophrenia or unipolar depression. However, few studies have explored the characteristics of self-processing in bipolar disorder (BD) during different clinical states. This study compared the differences in self-face recognition (SFR) among patients with bipolar mania (BPM), bipolar depression (BPD), bipolar remission (RM), and healthy controls (HC). Images of subject's own face, a familiar face, and an unfamiliar face were combined in pairs at a certain proportion to obtain three types of blended images. We then compared the tendency between BD and HC while judging two kinds of blended faces emerging from presentation software. The results showed that the BPM and BPD groups seemed to lack an advantage in self-recognition. Self-processing and familiarity processing were significantly enhanced in BPM patients, while only familiarity processing was enhanced in BPD. The severity of clinical symptoms was not significantly correlated with self-bias or familiarity bias in BD.

Neural timing of the other-race effect across the lifespan: A review

Face race influences the way we process faces, so that faces of a different ethnic group are processed for identity less efficiently than faces of one's ethnic group - a phenomenon known as the Other-Race Effect (ORE). Although widely replicated, the ORE is still poorly characterized in terms of its development and the underlying mechanisms. In the last two decades, the Event-Related Potential (ERP) technique has brought insight into the mechanisms underlying the ORE and has demonstrated potential to clarify its development. Here, we review the ERP evidence for a differential neural processing of own-race and other-race faces throughout the lifespan. In infants, race-related processing differences emerged at the N290 and P400 (structural encoding) stages. In children, race affected the P100 (early processing, attention) perceptual stage and was implicitly encoded at the N400 (semantic processing) stage. In adults, processing difficulties for other-race faces emerged at the N170 (structural encoding), P200 (configuration processing) and N250 (accessing individual representations) perceptual stages. Early in processing, race was implicitly encoded from other-race faces (N100, P200 attentional biases) and in-depth processing preferentially applied to own-race faces (N200 attentional bias). Encoding appeared less efficient (Dm effects) and retrieval less recollection-based (old/new effects) for other-race faces. Evidence admits the contribution of perceptual, attentional, and motivational processes to the development and functioning of the ORE, offering no conclusive support for perceptual or socio-cognitive accounts. Cross-racial and non-cross-racial studies provided convergent evidence. Future research would need to include less represented ethnic populations and the developmental population.

Recognition Mechanism of Dangerous Goods Marks: Evidence from an Event-Related Potential Study

Dangerous goods marks are the most effective means of alerting individuals to the potential dangers associated with the transport of dangerous goods. In order to gain a better understanding of how dangerous goods marks convey risk information, the cognitive processing of dangerous goods marks was examined by measuring event-related potentials (ERPs). We recruited 23 participants, and their ERP data were recorded. We discovered that the dangerous goods marks elicited a larger P200 amplitude and a smaller N300 amplitude, indicating that, compared to other marks, the dangerous goods marks exhibited stronger warning information and drew more attention from the subjects. Simultaneously, dangerous goods marks elicited insufficient emotional arousal in individuals. Therefore, these findings suggest that the designs of dangerous goods marks need to be improved, such as improving the graphic consistency. Changes in ERP patterns can be used to measure the risk perception level of dangerous goods marks, which can be used as an accurate indicator of the effectiveness of warning sign design. In addition, this study provides a theoretical foundation for the cognitive understanding mechanism of dangerous goods marks.

Eye size recognition of self and others among people with self-face dissatisfaction

Previous studies have shown that individuals visually recognize their eye size as larger than the actual. However, it is unclear whether this cognitive tendency occurs in people with high self-face dissatisfaction. Therefore, this study aimed to investigate whether the cognitive size of one's own and others' eyes differs according to the degree of self-face dissatisfaction. Participants comprised 32 college students (5 males, 27 females; age: 21.3 ± 2.11) who completed the Face Dissatisfaction Scale (FDS) and a face recognition memory task. The task was to choose whether their or their friends' eyes in the face photos with changed eye size were larger or smaller than their actual eye size. The cognitively equivalent eye size to the actual one was estimated from a psychophysical function. We conducted a correlation analysis of the total scores on the FDS and the point of subjective equality (PSE) of eye size. We found a high negative correlation between the FDS and the PSE of own eye size. There was also a high positive correlation between the FDS and the PSE for all others' faces. Thus, high self-face dissatisfaction is differentially associated with cognitive distortions of the face, depending on whether it is self or other.

Bone conduction facilitates self-other voice discrimination

One's own voice is one of the most important and most frequently heard voices. Although it is the sound we associate most with ourselves, it is perceived as strange when played back in a recording. One of the main reasons is the lack of bone conduction that is inevitably present when hearing one's own voice while speaking. The resulting discrepancy between experimental and natural self-voice stimuli has significantly impeded self-voice research, rendering it one of the least investigated aspects of self-consciousness. Accordingly, factors that contribute to self-voice perception remain largely unknown. In a series of three studies, we rectified this ecological discrepancy by augmenting experimental self-voice stimuli with bone-conducted vibrotactile stimulation that is present during natural self-voice perception. Combining voice morphing with psychophysics, we demonstrate that specifically self-other but not familiar-other voice discrimination improved for stimuli presented using bone as compared with air conduction. Furthermore, our data outline independent contributions of familiarity and acoustic processing to separating the own from another's voice: although vocal differences increased general voice discrimination, self-voices were more confused with familiar than unfamiliar voices, regardless of their acoustic similarity. Collectively, our findings show that concomitant vibrotactile stimulation improves auditory self-identification, thereby portraying self-voice as a fundamentally multi-modal construct.

Decoding subject's own name in the primary auditory cortex

Current studies have shown that perception of subject's own name (SON) involves multiple multimodal brain regions, while activities in unimodal sensory regions (i.e., primary auditory cortex) and their interaction with multimodal regions during the self-processing remain unclear. To answer this, we combined multivariate pattern analysis and dynamic causal modelling analysis to explore the regional activation pattern and inter-region effective connection during the perception of SON. We found that SON and other names could be decoded from the activation pattern in the primary auditory cortex. In addition, we found an excitatory effect of SON on connections from the anterior insula/inferior frontal gyrus to the primary auditory cortex, and to the temporoparietal junction. Our findings extended the current knowledge of self-processing by showing that primary auditory cortex could discriminate SON from other names. Furthermore, our findings highlighted the importance of influence of the insula on the primary auditory cortex during self-processing.

How do extrinsic cues influence consumers’ online hotel booking decisions? An event-related potential experiment

Booking decision is a typical decision-making behavior in hospitality, while the neural processing of it is still unclear. To address this issue, with the help of event-related potential (ERP), this work uncovered the neural mechanism of the influence of two extrinsic cues, namely, brand familiarity (familiar vs. unfamiliar) and online reviews (positive vs. negative) on online hotel booking decisions. Behavioral results indicated that the booking rate under the condition of positive reviews was higher than that of negative reviews. In addition, the response time in the case of familiar brands was longer than that of unfamiliar brands. ERP results showed that the P200 amplitude of familiar brands was smaller than that of unfamiliar brands, while for the late positive potential amplitude, the opposite was the case. It is suggested that in the early stage of cognitive processing, unfamiliar brands evoke more automatic and unconscious attention while in the later stage, familiar brands attract more conscious attention. This study also found that the N400 amplitude of negative online reviews was larger than that of positive online reviews, indicating that negative stimuli can result in a larger emotional conflicts than that of positive stimuli. This study provides new insights into the neural mechanism of online booking decisions in the hospitality.

Cosmetic makeup enhances facial attractiveness and affective neural responses

Although it is well established that cosmetic makeup enhances perceived facial attractiveness, few studies have examined whether facial makeup modulates neural responses to face images. This study investigated behavioral and attractiveness-related brain responses to self-applied makeup, focusing on the N170, early posterior negativity, P300, and late positive potential components of event-related brain potentials. A total of 77 Japanese women participated in two experiments (N = 34 and 43 for Experiments 1 and 2, respectively). Experiment 1 assessed the effects of self-applied makeup on attractiveness-related event-related potential amplitudes using facial images during a makeup identification task in which makeup was directly relevant to task demands. Experiment 2 examined the effects of self-applied makeup using images of one’s own face and another female’s face when performing a gender classification task, where the presence of makeup had no explicit connection to facial gender classification. In both experiments, faces with makeup were rated as more attractive and elicited more negative early posterior negativity and more positive late positive potential components, regardless of the participant’s own face or another person’s face. These findings suggest that people are spontaneously motivated to pay visual attention to faces with makeup, which supports the idea that makeup adds reward value to the facial appearance of the human. Moreover, neural evidence empirically confirmed that the benefits of makeup are not just limited to how others see your face but also extend to how you see your own face.

A featural account for own-face processing? Looking for support from face inversion, composite face, and part-whole tasks

It is widely accepted that face perception relies on holistic processing. However, this holistic advantage is not always found in the processing of the own face. Our study aimed to explore the role of holistic and featural processing in the identification of the own face, using three standard, but largely independent measures of holistic face processing: the face inversion task, the composite face task, and the part-whole task. Participants were asked to identify their face, a friend’s face, and an unfamiliar face in three different experimental blocks: (a) inverted versus upright; (b) top and bottom halves of the face aligned versus misaligned; and (c) facial features presented in isolation versus whole foil face context. Inverting a face impaired its identification, regardless of the identity. However, alignment effects were only found when identifying a friend or an unfamiliar face. In addition, a stronger feature advantage (i.e., better recognition for isolated features compared to in a whole-face context) was observed for the own face compared to the friend and unfamiliar faces. Altogether, these findings suggest that the own face is processed in a more featural manner but also relies on holistic processing. This work also highlights the importance of taking into consideration that different holistic processing paradigms could tap different forms of holistic processing.

Spatio-temporal brain dynamics of self-identity: an EEG source analysis of the current and past self

Current research on self-identity suggests that the self is settled in a unique mental representation updated across the lifespan in autobiographical memory. Spatio-temporal brain dynamics of these cognitive processes are poorly understood. ERP studies revealed early (N170-N250) and late (P3-LPC) waveforms modulations tracking the temporal processing of global face configuration, familiarity processes, and access to autobiographical contents. Neuroimaging studies revealed that such processes encompass face-specific regions of the occipitotemporal cortex, and medial cortical regions tracing the self-identity into autobiographical memory across the life span. The present study combined both approaches, analyzing brain source power using a data-driven, beamforming approach. Face recognition was used in two separate tasks: identity (self, close friend and unknown) and life stages (childhood, adolescence, adulthood) recognition. The main areas observed were specific-face areas (fusiform area), autobiographical memory areas (medial prefrontal cortex, parahippocampus, posterior cingulate cortex/precuneus), along with executive areas (dorsolateral prefrontal and anterior temporal cortices). The cluster-permutation test yielded no significant early effects (150-200 ms). However, during the 250-300 ms time window, the precuneus and the fusiform cortices exhibited larger activation to familiar compared to unknown faces, regardless of life stages. Subsequently (300-600 ms), the medial prefrontal cortex discriminates between self-identity vs. close-familiar and unknown. Moreover, significant effects were found in the cluster-permutation test specifically on self-identity discriminating between adulthood from adolescence and childhood. These findings suggest that recognizing self-identity from other facial identities (diachronic self) comprises the temporal coordination of anterior and posterior areas. While mPFC maintained an updated representation of self-identity (diachronic self) based on actual rewarding value, the dlPFC, FG, MTG, paraHC, PCC was sensitive to different life stages of self-identity (synchronic self) during the access to autobiographical memory.

Neural correlates of own name and own face processing in neurotypical adults scoring low versus high on symptomatology of autism spectrum disorder

Previous event-related potential (ERP) research showed reduced self-referential processing in autism spectrum disorder (ASD). As different self-related stimuli were studied in isolation, it is unclear whether findings can be ascribed to a common underlying mechanism. Further, it is unknown whether altered self-referential processing is also evident in neurotypicals scoring high on ASD symptomatology. We compared ERPs in response to one's own name and face (versus other names/faces) between neurotypical adults scoring high versus low on ASD symptomatology. Conform previous research, the parietal P3 was enhanced, both for own name and face, indicating a self-referential effect. The N250 was only enhanced for one's own face. However, the self-referential parietal P3 effect did not correlate between the names and faces conditions, arguing against a common underlying mechanism. No group effects appeared, neither for names nor faces, suggesting that reduced self-referential processing is not a dimensional ASD feature in the neurotypical population.

Breathing affects self-other voice discrimination in a bodily state associated with somatic passivity

A growing number of studies have focused on identifying cognitive processes that are modulated by interoceptive signals, particularly in relation to the respiratory or cardiac cycle. Considering the fundamental role of interoception in bodily self‐consciousness, we here investigated whether interoceptive signals also impact self‐voice perception. We applied an interactive, robotic paradigm associated with somatic passivity (a bodily state characterized by illusory misattribution of self‐generated touches to someone else) to investigate whether somatic passivity impacts self‐voice perception as a function of concurrent interoceptive signals. Participants' breathing and heartbeat signals were recorded while they performed two self‐voice tasks (self‐other voice discrimination and loudness perception) and while simultaneously experiencing two robotic conditions (somatic passivity condition; control condition). Our data reveal that respiration, but not cardiac activity, affects self‐voice perception: participants were better at discriminating self‐voice from another person’s voice during the inspiration phase of the respiration cycle. Moreover, breathing effects were prominent in participants experiencing somatic passivity and a different task with the same stimuli (i.e., judging the loudness and not identity of the voices) was unaffected by breathing. Combining interoception and voice perception with self‐monitoring framework, these data extend findings on breathing‐dependent changes in perception and cognition to self‐related processing.

Impact StatementThe contents of this page will be shown on the eTOC on the online version only. It will not be published as part of the article PDF.

We combined psychophysics with robotics and voice‐morphing technology to evaluate the effect of breathing on self‐voice perception. Our results show that listeners better perceive their own voice during inspiration, an effect that is modulated by self‐related bodily processing. This extends previous findings documenting the effect of interoceptive signals on perception and suggests that the bodily self may serve as a scaffold for cognition.

Attractiveness Evaluation and Identity of Self-face: The Effect of Sexual Dimorphism

The present study aims to explore the influence of masculine/feminine changes on the attractiveness evaluation of one's own face, and examine the relationship of this attractiveness evaluation and the similarities between masculine/feminine faces and original faces. A picture was taken from each participant and considered as his or her original self-face, and a male or female face with an average attractiveness score was adopted as the original other face. Masculinized and feminized transformations of the original faces (self-face, male other face, and female other face) into 100% masculine and feminine faces were produced with morphing software stepping by 2%. Thirty female participants and 30 male participants were asked to complete three tasks, i.e., to “like” or “not like” the original face judgment of a given face compared to the original face, to choose the most attractive face from a morphed facial clip, and to subjectively evaluate the attractiveness and similarity of morphed faces. The results revealed that the acceptable range of masculine/feminine transformation for self-faces was narrower than that for other faces. Furthermore, the attractiveness ratings for masculinized or femininized self-faces were correlated with the similarity scores of the faces with the original self-faces. These findings suggested that attractiveness enhancement of self-face through masculinity/femininity must be within reasonable extent and take into account the similarity between the modified faces and the original self-face.

Overestimation of eye size: People see themselves with bigger eyes in a holistic approach

A face contains crucial information for identification; moreover, face recognition is superior to other types of recognition. Notably, one's own face is recognized better than other familiar faces. However, it is unclear whether one's own face, especially one's own internal facial features, is represented more accurately than other faces. Here, we investigated how one's own internal facial features were represented. We conducted a psychological experiment in which the participants were required to adjust eye size to the real size in photos of their own or well-known celebrities' faces. To investigate why individuals' own and celebrity facial representations were different, two types of photos were prepared, with and without external features. It was found that the accuracy of eye size for one's own face was better than that for celebrities' faces in the condition without external features, in which holistic processing was less involved than in the condition with external features. This implies that the eye size of one's own face was represented more accurately than that of other familiar faces when external features were removed. Moreover, the accuracy of the eye size of one's own face in the condition with external features was worse than that in the condition without external features; the adjusted eye size in the condition with external features was larger than that in the condition without external features. In contrast, for celebrities' faces, there was no significant difference between the conditions with and without external features. The adjusted eye sizes in all conditions were overestimated compared to real eye sizes. Previous research indicated that eye size was adjusted to a larger size when evaluating as more attractive, in which the evaluation is related to holistic processing. Based on this perspective, it could be that one's own face was represented as more attractive in the condition with external features in the current study. Taken together, the results indicated that the representation of own eye size, which is an internal facial feature, was affected by the visibility of the external features.

The upside-down self: One's own face recognition is affected by inversion

One's own face is recognized more efficiently than any other face, although the neural mechanisms underlying this phenomenon remain poorly understood. Considering the extensive visual experience that we have with our own face, some authors have proposed that self-face recognition involves a more analytical perceptual strategy (i.e., based on face features) than other familiar faces, which are commonly processed holistically (i.e., as a whole). However, this hypothesis has not yet been tested with brain activity data. In the present study, we employed an inversion paradigm combined with event-related potential (ERP) recordings to investigate whether the self-face is processed more analytically. Sixteen healthy participants were asked to identify their own face and a familiar face regardless of its orientation, which could either be upright or inverted. ERP analysis revealed an enhanced amplitude and a delayed latency for the N170 component when faces were presented in an inverted orientation. Critically, both the self and a familiar face were equally vulnerable to the inversion effect, suggesting that the self-face is not processed more analytically than a familiar face. In addition, we replicated the recent finding that the attention-related P200 component is a specific neural index of self-face recognition. Overall, our results suggest that the advantage for self-face processing might be better explained by the engagement of self-related attentional mechanisms than by the use of a more analytical visuoperceptual strategy.

More or less of me and you: self-relevance augments the effects of item probability on stimulus prioritization

Self-relevance exerts a powerful influence on information processing. Compared to material associated with other people, personally meaningful stimuli are prioritized during decision-making. Further exploring the character of this effect, here we considered the extent to which stimulus enhancement is impacted by the frequency of self-relevant versus friend-relevant material. In a matching task, participants reported whether shape-label stimulus pairs corresponded to previously learned associations (e.g., triangle = self, square = friend). Crucially however, before the task commenced, stimulus-based expectancies were provided indicating the probability with which both self- and friend-related shapes would be encountered. The results revealed that task performance was impacted by the frequency of stimulus presentation in combination with the personal relevance of the items. When self- and friend-related shapes appeared with equal frequencies, a self-prioritization effect emerged (Expt. 1). Additionally, in both confirmatory (Expt. 2) and dis-confirmatory (Expt. 3) task contexts, stimuli that were encountered frequently (vs. infrequently) were prioritized, an effect that was most pronounced for self-relevant (vs. friend-relevant) items. Further computational analyses indicated that, in each of the reported experiments, differences in performance were underpinned by variation in the rate of information uptake, with evidence extracted more rapidly from self-relevant compared to friend-relevant stimuli. These findings advance our understanding of the emergence and origin of stimulus-prioritization effects during decisional processing.

Does mobile payment change consumers' perception during payment process? -An ERP study

Innovative payment methods have been getting worldwide attention. Exploring the mechanisms behind consumers' purchase behaviors modulated by different payment methods was critical but challenging. In this paper, we proposed a 2 (payment methods: cash payment vs mobile payment) × 2 (price levels of products: high vs low) Event-Related Potentials (ERPs) experiment to study the difference of cash payment and mobile payment on consumers' purchase intention of products in different price level from a neuroscience perspective. Greater P200 amplitude was found in mobile payment condition, which meant that mobile payment captured more early attention resources than cash. Larger N270 amplitude was found in cash payment condition as the participants had to spend more cognitive resources and struggled more when using cash. Moreover, lower N270 amplitude was found in high-price product condition, which indicated that when there were limited cognitive resources, the affective process played a dominating role. Specifically, buying the high-price products with mobile payment, the consumers would experience the pleasure of consumption more rather than the pain of paying. The study offers insights on the cognitive process of consumers when they pay with different methods.

Self-face and emotional faces-are they alike?

The image of one’s own face is a particularly distinctive feature of the self. The self-face differs from other faces not only in respect of its familiarity but also in respect of its subjective emotional significance and saliency. The current study aimed at elucidating similarities/dissimilarities between processing of one’s own face and emotional faces: happy faces (based on the self-positive bias) and fearful faces (because of their high perceptual saliency, a feature shared with self-face). Electroencephalogram data were collected in the group of 30 participants who performed a simple detection task. Event-related potential analyses indicated significantly increased P3 and late positive potential amplitudes to the self-face in comparison to all other faces: fearful, happy and neutral. Permutation tests confirmed the differences between the self-face and all three types of other faces for numerous electrode sites and in broad time windows. Representational similarity analysis, in turn, revealed distinct processing of the self-face and did not provide any evidence in favour of similarities between the self-face and emotional (either negative or positive) faces. These findings strongly suggest that the self-face processing do not resemble those of emotional faces, thus implying that prioritized self-referential processing is driven by the subjective relevance of one’s own face.

My own face looks larger than yours: A self-induced illusory size perception

Size perception of visual objects is highly context dependent. Here we report a novel perceptual size illusion that the self-face, being a unique and distinctive self-referential stimulus, can enlarge its perceived size. By using a size discrimination paradigm, we found that the self-face was perceived as significantly larger than the other-face of the same size. This size overestimation effect was not due to the familiarity of the self-face, since it could be still observed when the self-face was directly compared with a famous face. More crucially, such illusion effect could be extended to a new cartoon face that was transiently associated with one's own face and could also exert further contextual influences on visual size perception of other objects. These findings together highlight the role of self-awareness in visual size perception and point to a special mechanism of size perception tuned to self-referential information.

The N170 is Sensitive to Long-term (Personal) Familiarity of a Face Identity

The N170 is a large deflection of the human electroencephalogram (EEG), peaking at about 170 milliseconds over the occipito-temporal cortex after the sudden onset of a face stimulus. The N170 reflects perceptual awareness of a face and its onset corresponds to the emergence of reliable face-selectivity in the human brain. However, whether sensitivity to the long-term familiarity of a face identity emerges already at this early time-point remains debated. Here we provide a brief survey of the 45 published studies comparing the N170 response to unfamiliar and familiar (famous, experimentally familiarized, personally familiar and own) faces. Even though effects of familiarity on the N170 are relatively small and inconsistent across studies, this overview indicates that face familiarity significantly increases the N170 amplitude. This effect is especially present for personally familiar faces, learned in natural conditions. In the human brain, effects linked to familiarity with specific facial identities therefore appear to emerge between 150 and 200 ms in occipito-temporal brain regions, i.e., shortly after the onset of face-selectivity but at the same time as the earliest high-level effects of immediate unfamiliar face identity repetition. This observation challenges standard neurocognitive models with a clear-cut distinction between perceptual and memory stages in human face recognition.

The self-face captures attention without consciousness: Evidence from the N2pc ERP component analysis

It is well established that stimuli representing or associated with ourselves, like our own name or an image of our own face, benefit from preferential processing. However, two key questions concerning the self-prioritization mechanism remain to be addressed. First, does it operate in an automatic manner during the early processing, or rather in a more controlled fashion at later processing stages? Second, is it specific to the self-related stimuli, or can it be activated also by other stimuli that are familiar or salient? We conducted a dot-probe experiment to investigate the mechanism behind the attentional prioritization of the self-face image and to tackle both questions. The former, by employing a backwards masking procedure to isolate the early and preconscious processing stages. The latter, by investigating whether a face that becomes visually familiar due to repeated presentations is able to capture attention in a similar manner as the self-face. Analysis of the N2pc ERP component revealed that the self-face image automatically captures attention, both when processed consciously and unconsciously. In contrast, the visually familiar face did not attract attention, neither in the conscious, nor in the unconscious condition. We conclude that the self-prioritization mechanism is early and automatic, and is not triggered by mere visual familiarity. More generally, our results provide further evidence for efficient unconscious processing of faces, and for dissociation between attention and consciousness.

Like the back of my hand: Visual ERPs reveal a specific change detection mechanism for the bodily self

The ability to identify our own body is considered a pivotal marker of self-awareness. Previous research demonstrated that subjects are more efficient in the recognition of images representing self rather than others' body effectors (self-advantage). Here, we verified whether, at an electrophysiological level, bodily-self recognition modulates change detection responses. In a first EEG experiment (discovery sample), event-related potentials (ERPs) were elicited by a pair of sequentially presented visual stimuli (vS1; vS2), representing either the self-hand or other people's hands. In a second EEG experiment (replicating sample), together with the previously described visual stimuli, also a familiar hand was presented. Participants were asked to decide whether vS2 was identical or different from vS1. Accuracy and response times were collected. In both experiments, results confirmed the presence of the self-advantage: participants responded faster and more accurately when the self-hand was presented. ERP results paralleled behavioral findings. Anytime the self-hand was presented, we observed significant change detection responses, with a larger N270 component for vS2 different rather than identical to vS1. Conversely, when the self-hand was not included, and even in response to the familiar hand in Experiment 2, we did not find any significant modulation of the change detection responses. Overall our findings, showing behavioral self-advantage and the selective modulation of N270 for the self-hand, support the existence of a specific mechanism devoted to bodily-self recognition, likely relying on the multimodal (visual and sensorimotor) dimension of the bodily-self representation. We propose that such a multimodal self-representation may activate the salience network, boosting change detection effects specifically for the self-hand.

The Behavioral and ERP Responses to Self- and Other- Referenced Adjectives

The aim was to investigate behavioral reactions and event-related potential (ERP) responses in healthy participants under conditions of personalized attribution of emotional appraisal vocabulary to one-self or to other people. One hundred and fifty emotionally neutral, positive and negative words describing people's traits were used. Subjects were asked to attribute each word to four types of people: one-self, loved, unpleasant and neutral person. The reaction time during adjectives attribution to one-self and a loved person was shorter than during adjectives attribution to neutral and unpleasant people. Self-related adjectives induced higher amplitudes of the N400 ERP peak in the medial cortical areas in comparison with adjectives related to other people. The amplitude of P300 and P600 depended on the emotional valence of assessments, but not on the personalized attribution. The interaction between the attribution effect and the effect of emotional valence of assessments was observed for the N400 peak in the left temporal area. The maximal amplitude of N400 was revealed under self-attributing of emotionally positive adjectives. Our results supported the hypothesis that the emotional valence of assessments and the processing of information about one-self or others were related to the brain processes that differ from each other in a cortical localization or time dynamics.

Am I the same person across my life span? An event-related brain potentials study of the temporal perspective in self-identity

While self-identity recognition has been largely explored, less is known on how self-identity changes as a function of time. The present work aims to explore the influence of the temporal perspective on self-identity by studying event-related brain potentials (ERP) associated with face processing. To this purpose, participants had to perform a recognition task in two blocks with different task demands: (i) identity recognition (self, close-friend, unknown), and (ii) life stage recognition (adulthood -current-, adolescence, and childhood). The results showed that the N170 component was sensitive to changes in the global face configuration when comparing adulthood with other life stages. The N250 was the earliest neural marker discriminating self from other identities and may be related to a preferential deployment of attentional resources to recognize own face. The P3 was a robust index of self-specificity, reflecting stimulus categorization and presumably adding an emotional value. The results of interest emerged for the subsequent late positive complex (LPC). The larger amplitude for the LPC to the self-face was probably associated with further personal significance. The LPC, therefore, was able to distinguish the continuity of the self over time (i.e., between current self and past selves). Likewise, this component also could discriminate, at each life stage, the self-identity from other identities (e.g., between past self and past close-friend). This would confirm a remarkable role of the LPC reflecting higher self-relevance processes. Taken together, the neural representation of oneself (i.e., "I am myself") seems to be stable and also updated across time.

External (Versus Internal) Facial Features Contribute Most to Repetition Priming in Facial Recognition: ERP Evidence

Previous event-related potential (ERP) research demonstrated four successive ERP components in the repetition priming of human face recognition: P100, N170, N250r, and N400. While these components correspond, respectively, to the four stages proposed by the interactive activation and competition (IAC) model, there has been no emphasis in past research on how internal and external facial features affect repetition priming and the sensitivity of these ERP components to item interval. This study was designed to address these issues. We used faces of celebrities as targets, including completely familiar faces, familiar internal feature faces, and familiar external feature faces. We displayed a target face either immediately following its prime (immediate repetition) or after a delay with interference from a presentation of two other faces (delayed repetition). ERP differences at P100 and N170 were nearly statistically non-significant; familiar faces and familiar external feature faces were associated with reliable ERP signals of N250r and N400 in the immediate repetition condition. For delayed repetition, however, N250r and N400 signals were only preserved for the familiar external feature faces. The differences of these ERP components suggest that, compared with internal facial features, external features of a previously presented face contribute more to brain-based facial repetition priming, particularly during the last two stages of the IAC model.

Stranger to my face: Top-down and bottom-up effects underlying prioritization of images of one's face

Recent studies suggest that we rapidly and effortlessly associate neutral information with the self, leading to subsequent prioritization of this information in perception. However, the exact underlying processes behind these effects are not fully known. Here, we focus specifically on top-down and bottom-up processes involved in self-prioritization, and report results from three experiments involving face detection, using a sequential match-non-match task. Across the three experiments we asked participants to associate an unfamiliar face with the self (Experiment 1), to associate one's face with a stranger's name (Experiment 2), and to establish both associations simultaneously (Experiment 3). We found that while participants showed evidence of bottom-up prioritization of their real faces, they did not show such an effect for self-associated strangers' faces. However, the participants showed a robust self-related top-down effect; when presented with a self-related cue, they were later faster at classifying both subsequent correct and incorrect targets. Together, our results suggest that self-prioritization is underpinned by distinct top-down and bottom-up processes. We discuss our findings in the context of the proposal that the self acts as an "integrative glue", and suggest an interpretation of our results within the framework of predictive coding.

The 'Narcissus Effect': Top-down alpha-beta band modulation of face-related brain areas during self-face processing

Self-related information, such as one's own face, is prioritized by our cognitive system. Whilst recent theoretical developments suggest that this is achieved by an interplay between bottom-up and top-down attentional mechanisms, their underlying neural dynamics are still poorly understood. Furthermore, it is still matter of discussion as to whether these attentional mechanisms are truly self-specific or instead driven by face familiarity. To address these questions, we used EEG to record the brain activity of twenty-five healthy participants whilst identifying their own face, a friend's face and a stranger's face. Time-frequency analysis revealed a greater sustained power decrease in the alpha and beta frequency bands for the self-face, which emerged at late latencies and was maintained even when the face was no longer present. Critically, source analysis showed that this activity was generated in key brain regions for self-face recognition, such as the fusiform gyrus. As in the Myth of Narcissus, our results indicate that one's own face might have the potential to hijack attention. We suggest that this effect is specific to the self and driven by a top-down attentional control mechanism, which might facilitate further processing of personally relevant events.

Influence of sexual dimorphism on the attractiveness evaluation of one's own face

The present study aimed to explore the influence of sexual dimorphism on the evaluation of the attractiveness of one's own face. In the experiment, a masculinized and a feminized version of the self-faces of the participants were obtained by transferring the original faces toward the average male or female face. The participants were required to rate the attractiveness of three types (original, masculine, feminine) of their own faces and the other participants' faces in same-sex and opposite-sex contexts. The results revealed that the participants rated their own faces as more attractive than other participants rated them regardless of the sexually dimorphic type (original, masculine, feminine) or the evaluation context. More importantly, the male and female participants showed different preferences for the three types of self-faces. Specifically, in the same-sex context, the female participants rated their own original faces as significantly more attractive than the masculine and feminine faces, and the male participants rated their own masculine faces as significantly more attractive than the feminine faces; while in the opposite-sex context, no significant difference among the attractiveness scores of the three types of self-faces was found in both the male and female participants. The present study provides empirical evidence of the influence of sexual dimorphism on the evaluation of the attractiveness of self-faces.

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.