Categorical perception effects for facial identity in robustly represented familiar and self-faces: the role of configural and featural information

Unlocking the potential of 'passive' modulation: How sensory stimulation shapes hand and face size

Knowledge of the body size is intricately tied to multisensory integration processes that rely on the dynamic interplay of top-down and bottom-up mechanisms. Recent years have seen the development of passive sensory stimulation protocols aimed at investigating the modulation of various cognitive functions, primarily inducing perceptual learning and behaviour change without the need for extensive training. Given that reductions in sensory input have been associated with alterations in body size perception, it is reasonable to hypothesize that increasing sensory information through passive sensory stimulation could similarly influence the perception of the size of body parts. The primary aim of this study was to investigate the potential modulatory effects of passive sensory stimulation on the perception of hand and face size in a group of young adults. Passive sensory stimulation effectively modulated the size representation of the stimulated hand, supporting the notion that access to somatosensory and proprioceptive information is prioritised for the hands but may not extend to the face. Increased somatosensory input resulted in a reduction of distortion, providing evidence for bottom-up modulation of size representation. Passive sensory stimulation can induce subjective changes in body size perception without the need for extensive training. This paradigm holds promise as a potential alternative for modulating distorted size representation in individuals with body representational deficits.

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.

Familiarity, orientation, and realism increase face uncanniness by sensitizing to facial distortions

The uncanny valley predicts aversive reactions toward near-humanlike entities. Greater uncanniness is elicited by distortions in realistic than unrealistic faces, possibly due to familiarity. Experiment 1 investigated how familiarity and inversion affect uncanniness of facial distortions and the ability to detect differences between the distorted variants of the same face (distortion sensitivity). Familiar or unfamiliar celebrity faces were incrementally distorted and presented either upright or inverted. Uncanniness ratings increased across the distortion levels, and were stronger for familiar and upright faces. Distortion sensitivity increased with increasing distortion difference levels, again stronger for familiar and upright faces. Experiment 2 investigated how face realism, familiarity, and face orientation interacted for the increase of uncanniness across distortions. Realism increased the increase of uncanniness across the distortion levels, further enhanced by upright orientation and familiarity. The findings show that familiarity, upright orientation, and high face realism increase the sensitivity of uncanniness, likely by increasing distortion sensitivity. Finally, a moderated linear function of face realism and deviation level could explain the uncanniness of stimuli better than a quadratic function. A re-interpretation of the uncanny valley as sensitivity toward deviations from familiarized patterns is discussed.

Are covered faces eye-catching for us? The impact of masks on attentional processing of self and other faces during the COVID-19 pandemic

During the COVID-19 pandemic, we have been confronted with faces covered by surgical-like masks. This raises a question about how our brains process this kind of visual information. Thus, the aims of the current study were twofold: (1) to investigate the role of attention in the processing of different types of faces with masks, and (2) to test whether such partial information about faces is treated similarly to fully visible faces. Participants were tasked with the simple detection of self-, close-other's, and unknown faces with and without a mask; this task relies on attentional processes. Event-related potential (ERP) findings revealed a similar impact of surgical-like masks for all faces: the amplitudes of early (P100) and late (P300, LPP) attention-related components were higher for faces with masks than for fully visible faces. Amplitudes of N170 were similar for covered and fully visible faces, and sources of brain activity were located in the fusiform gyri in both cases. Linear Discriminant Analysis (LDA) revealed that irrespective of whether the algorithm was trained to discriminate three types of faces either with or without masks, it was able to effectively discriminate faces that were not presented in the training phase.

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.

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.

Early Capture of Attention by Self-Face: Investigation Using a Temporal Order Judgment Task

Earlier work on self-face processing has reported a bias in the processing of self-face result in faster response to self-face in comparison to other familiar and unfamiliar faces (termed as self-face advantage or SFA). Even though most studies agree that the SFA occurs due to an attentional bias, there is little agreement regarding the stage at which it occurs. While a large number of studies show self-face influencing processing later at disengagement stage, early event-related potential components show differential activity for the self-face suggesting that SFA occurs early. We address this contradiction using a cueless temporal order judgment task that allows us to investigate early perceptual processing, while bias due to top-down expectation is controlled. A greater shift in point of subjective simultaneity for self-face would indicate a greater processing advantage at early perceptual stage. With help of two experiments, we show an early perceptual advantage for self-face, compared to both a friend's face and an unfamiliar face (Experiment 1). This advantage is present even when the effect of criterion shift is minimized (Experiment 2). Interestingly, the magnitude of advantage is similar for self-friend and self-unfamiliar pair. The evidence from the two experiments suggests early capture of attention as a likely reason for the SFA, which is present for the self-face but not for other familiar faces.

STOP SHOUTING AT ME: The Influence of Case and Self-Referencing on Explicit and Implicit Memory

Evidence suggests that physical changes in word appearance, such as those written in all capital letters, and the use of effective encoding strategies, such as self-referential processing, improves memory. In this study we examined the extent both physical changes in word appearance (case) and encoding strategies engaged at study influence memory as measured by both explicit and implicit memory measures. Participants studied words written in upper and lower case under three encoding conditions (self-reference, semantic control, case judgment), which was followed by an implicit (word stem completion) and then an explicit (item and context) memory test. There were two primary results. First, analyses indicated a case enhancement effect for item memory where words written in upper case were better remembered than lower case, but only when participants were prompted to attend to the case of the word. Importantly, this case enhancement effect came at a cost to context memory for words written in upper case. Second, self-referencing increased explicit memory performance relative to control, but there was no effect on implicit memory. Overall, results suggest an item-context memory trade-off for words written in upper case, highlighting a potential downside to writing in all capital letters, and further, that both physical changes to the appearance of words and differing encoding strategies have a strong influence on explicit, but not implicit memory.

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.

Categorical Perception of Control

The self is a distinct entity from the rest of the world, and actions and sensory feedback are our channels of interaction with the external world. This study examined how the sense of control influences people's perception of sensorimotor input under the framework of categorical perception. Twenty human participants (18 males, two females) took part in both experiments. Experiment 1 showed that the sensitivity (d') of detecting a 20% change in control from no change was higher when the changes occurred at the control-category boundary than within each category. Experiment 2 showed that the control categories greatly affected early attention allocation, even when the judgment of control was unnecessary to the task. Taken together, these results showed that our perceptual and cognitive systems are highly sensitive to small changes in control that build up to a determinant change in the control category within a relatively narrow boundary zone between categories, compared with a continuous, gradual physical change in control.

Rule-based or information-integration category: processing of the self-face

This study investigated the differences between categorizing the self-face and other faces. Additionally, the study aimed to determine whether self-face categorization is consistent with dual-system categorization, such as in the competition between verbal and implicit systems (COVIS) model, or whether the self-face uses different categorizing methods than those used with other faces. The experiment adopted a dual-task paradigm to examine how participants complete rule-based/information-integration categorization tasks of the self-face/other faces and their method of processing when a numerical Stroop task was introduced. Results indicated that participants processed the self-face better than other faces in rule-based categorization, and there was no significant difference between categorization of the self-face and other faces during a single or dual task. This suggests there is a self-processing advantage in classification tasks; however, categorization based on face stimuli is not consistent with the COVIS model. Face categorization has a self-advantage effect, and categorization of human faces is distinctive from other types of categorization.

The effect of self-focus on personal and social foraging behaviour

The continuous balancing of the risks and benefits of exploiting known options or exploring new opportunities is essential to human life. We forage for new opportunities when they are deemed to be more attractive than the available option, but this decision to forage also entails costs. People differ in their propensity to exploit or forage, and both the social circumstances and our individual value orientations are likely influences. Here, participants made foraging decisions for themselves and for a charity of their choice in two paradigms: one that features two distinct modes of decision-making (foraging vs classical economic decision-making) and one which is more directly related to the classical animal foraging and ethology literature. Across both paradigms, individuals who possessed a stronger self-focused value orientation obtained more rewards when they were allowed to forage for themselves rather than the charity. Neuroimaging during the tasks revealed that this effect was associated with activity in the dorsal anterior cingulate cortex (dACC) in that more self-focused individuals showed lower activity in dACC for the self-condition relative to the other condition. This evidence reveals a dynamic interplay between foraging outcomes and the higher-order value system of individuals.

Aging Strikes the Self-Face Advantage in Featural Processing

Background/Study Context: The face is the most distinctive physical feature of a person. Previous work has shown that one's own face (self-face) is advantageous in perception. Here the authors investigate how aging influences the configural and featural processing of self-face.

METHODS

Older and young adults searched for their own faces and faces of strangers (Experiment 1) or acquaintances (Experiment 2) among distractor faces. The configural and featural processing of faces was assessed with face inversion in Experiment 1 and with changes in point of view in Experiment 2.

RESULTS

Experiment 1 revealed a robust self-face advantage for upright faces in both young and older adults. A similar advantage was observed for inverted faces in young but not in older adults. Experiment 2 revealed a self-face advantage in older adults regardless of the point of view; in young adults, however, the self-face advantage only emerged for frontal view faces.

CONCLUSION

The present study shows that older adults have a self-face advantage in configural but not in featural processing. The authors suggest that the impairment in featural processing in older adults is likely the result of age-related changes in perceptual experience.

The Influence of Self-Referential Processing on Attentional Orienting in Frontoparietal Networks

Self-referential processing refers to the processing of information relevant to oneself and plays an important role in cognition. Behavioral studies have shown that directional cue stimuli have a qualitatively different function during attentional orienting after presentation of the cue associated with the self. However, it is necessary to determine how neural activity is influenced by self-referential processing during attentional orienting. The present study involved establishing an association between non-predictive arrow cues and the "self" during a training task and then investigating the influence of self-referential processing on neural activity during attentional orienting. Enhanced neural activity was observed in cortical midline structures (CMS) during the use of self- vs. neutral-arrow cues, which suggests that the arrow associated with the "self" triggered self-referential processing during attentional orienting due to the experiences of the participant in the training task. Comparison of obtained under the incongruent and congruent conditions revealed a qualitative difference in neural activities between the self- and neutral-arrow cues associated with attentional orienting. Furthermore, when the neutral-arrow cue was treated as a baseline condition, neural activity was reduced in the frontoparietal attention networks by self-referential processing under the incongruent condition, but it was enhanced under the congruent condition. Thus, the stimulus modulated subsequent attentional neural processes after being associated with the self as a cue, which indicates that this process may be triggered by self-reference to automatically and effectively capture information. Our findings extend those of previous behavioral studies of neural activity, suggesting that directional cues were qualitatively influenced by self-referential processing, and showed different functions during attentional orienting. Moreover, the present study provides important evidence of how self-referential processing affects attentional orienting in the frontoparietal network. Highlights -Enhanced activity was observed in CMS due to self-referential processing.-The influence of self-referential processing differed in the frontoparietal network.-Activity was enhanced by self-referential processing under the congruent condition.-Activity was reduced by self-referential processing under the incongruent condition.

Hemispheric asymmetry in discriminating faces differing for featural or configural (second-order relations) aspects

The human capacity to discriminate among different faces relies on distinct parallel subprocesses, based either on the analysis of configural aspects or on the sequential analysis of the single elements of a face. A particular type of configural processing consists of considering whether two faces differ in terms of internal spacing among their features, referred to as second-order relations processing. Findings from electrophysiological, neuroimaging, and lesion studies suggest that, overall, configural processes rely more on the right hemisphere, whereas analysis of single features would involve more the left. However, results are not always consistent, and behavioral evidence for a right-hemisphere specialization in second-order relations processing is lacking. Here, we used divided visual field presentation to investigate the possible different contributions of the two hemispheres to face discrimination based on relational versus featural processing. Our data indicate a right-hemispheric specialization in relational processing of upright (but not inverted) faces. Furthermore, we provide evidence regarding the involvement of both the right and left hemispheres in the processing of faces differing for inner features, suggesting that both analytical and configural modes of processing are at play.

Do I have my attention? Speed of processing advantages for the self-face are not driven by automatic attention capture

We respond more quickly to our own face than to other faces, but there is debate over whether this is connected to attention-grabbing properties of the self-face. In two experiments, we investigate whether the self-face selectively captures attention, and the attentional conditions under which this might occur. In both experiments, we examined whether different types of face (self, friend, stranger) provide differential levels of distraction when processing self, friend and stranger names. In Experiment 1, an image of a distractor face appeared centrally - inside the focus of attention - behind a target name, with the faces either upright or inverted. In Experiment 2, distractor faces appeared peripherally - outside the focus of attention - in the left or right visual field, or bilaterally. In both experiments, self-name recognition was faster than other name recognition, suggesting a self-referential processing advantage. The presence of the self-face did not cause more distraction in the naming task compared to other types of face, either when presented inside (Experiment 1) or outside (Experiment 2) the focus of attention. Distractor faces had different effects across the two experiments: when presented inside the focus of attention (Experiment 1), self and friend images facilitated self and friend naming, respectively. This was not true for stranger stimuli, suggesting that faces must be robustly represented to facilitate name recognition. When presented outside the focus of attention (Experiment 2), no facilitation occurred. Instead, we report an interesting distraction effect caused by friend faces when processing strangers' names. We interpret this as a "social importance" effect, whereby we may be tuned to pick out and pay attention to familiar friend faces in a crowd. We conclude that any speed of processing advantages observed in the self-face processing literature are not driven by automatic attention capture.

Lesion-symptom mapping of self-prioritization in explicit face categorization: distinguishing hypo- and hyper-self-biases

People make faster familiarity decisions for their own face compared with a familiar other. Lesion studies diverge on whether this self-face prioritization (SFP) effect is associated with functional processes isolated in the left or right hemispheres. To assess both decreases (hypo-) and increases (hyper-) in SFP after brain lesion, we asked patients with chronic deficits to perform familiarity judgments to images of their own face, a familiar other, or unfamiliar faces. Of 30 patients, 7 showed hypo- and 6 showed hyper-self-bias effects, comparing responses with their own faces versus responses with a familiar other. Hyper-self-bias correlated with reduced executive control function and, at a neural level, this was associated with lesions to the left prefrontal and superior temporal cortices. In contrast, reduced self-prioritization was associated with damage to the right inferior temporal structures including the hippocampus and extending to the fusiform gyrus. In addition, lesions affecting fibers crossing the right temporal cortex, potentially disconnecting occipital-temporal from frontal regions, diminished the self-bias effect. The data highlight that self-prioritized face processing is linked to regions in the right hemisphere associated with face recognition memory and it also calls on executive processes in the left hemisphere that normally modulate self-prioritized attention.

Predicting the accuracy of facial affect recognition: the interaction of child maltreatment and intellectual functioning

Previous research demonstrates that both child maltreatment and intellectual performance contribute uniquely to the accurate identification of facial affect by children and adolescents. The purpose of this study was to extend this research by examining whether child maltreatment affects the accuracy of facial recognition differently at varying levels of intellectual functioning. A sample of maltreated (n=50) and nonmaltreated (n=56) adolescent females, 14 to 19 years of age, was recruited to participate in this study. Participants completed demographic and study-related questionnaires and interviews to control for potential psychological and psychiatric confounds such as symptoms of posttraumatic stress disorder, negative affect, and difficulties in emotion regulation. Participants also completed an experimental paradigm that recorded responses to facial affect displays starting in a neutral expression and changing into a full expression of one of six emotions: happiness, sadness, anger, disgust, fear, or surprise. Hierarchical multiple regression assessed the incremental advantage of evaluating the interaction between child maltreatment and intellectual functioning. Results indicated that the interaction term accounted for a significant amount of additional variance in the accurate identification of facial affect after controlling for relevant covariates and main effects. Specifically, maltreated females with lower levels of intellectual functioning were least accurate in identifying facial affect displays, whereas those with higher levels of intellectual functioning performed as well as nonmaltreated females. These results suggest that maltreatment and intellectual functioning interact to predict the recognition of facial affect, with potential long-term consequences for the interpersonal functioning of maltreated females.