The human ability to suppress inappropriate or automatic responses is crucial for flexible and socially adaptive behavior. Inhibitory control is influenced by prominent environmental cues, including visual information gathered from the perception of others. Among the most salient features of people we interact with, face race stands out as a particularly powerful visual signal. Despite considerable research on face race perception and categorization, and recent evidence on cognitive control, the extent to which task-relevant face race influences inhibition remains unclear, yet relevant. To address this issue, we recorded the electrophysiological signals of West European participants while they performed a Go/No-Go task using West European (WE) and East Asian (EA) faces as stimuli targets. At the behavioral level, inhibitory efficiency was modulated by face race, with participants showing enhanced performance when inhibiting EA faces compared to WE ones. At the neural level, results revealed race-related modulation at both perceptual and post-perceptual processing stages. EA faces elicited a stronger P100, and a race effect on the No-Go P3 emerged, with greater amplitudes during its rising phase and anticipated latency for EA stimuli. Notably, the strength of the behavioral race effect correlated with the neural amplitude within time and location consistent with the No-Go P3. These results suggest modulation of the inhibitory cascade by task-relevant face race, spanning early perceptual and later control-related neural responses, and aligned overt effects on behavior.

Racial-category information in faces is visually and socially salient, and is rapidly extracted by the human brain. Yet, its electrophysiological encoding remains unclear. Event-related potentials findings are mixed, reporting contradictory effects of race on neural responses. To inform this debate, we used fast periodic visual stimulation (FPVS), an alternative objective and implicit method to measure neural face categorization. In Experiment 1, Western European participants viewed a 6 Hz stream of same- or other-race faces with periodic oddball faces from the alternate race. Results showed no above-noise-level race discrimination responses. In Experiment 2, oddball faces were embedded in object streams, presented upright or inverted, to test whether race modulates face categorization. Neural face categorization responses were above noise level for both same- and other-race faces. Importantly, while upright stimuli showed similar responses to both races, inversion selectively reduced responses to same-race faces, resulting in stronger neural responses to other-race faces. These findings suggest that face inversion affects neural responses based on visual expertise with face categories. Overall, our results demonstrate that racial-category information is robustly indexed by FPVS, highlighting this method as a powerful neurofunctional tool to study social vision.

Race is rapidly and effortlessly extracted from faces. Previous fMRI studies have reported race-related modulations in the bilateral Fusiform Face Areas (FFAs) and Occipital Face Areas (OFAs) during the categorization of faces by race. However, our recent findings revealed a comparable Other-Race Categorization Advantage between a well-studied case of pure acquired prosopagnosia—patient PS—and healthy controls. Notably, PS demonstrated faster categorization by race of other—compared to same-race faces, similar to healthy participants, despite sustaining lesions in the right OFA (rOFA) and left FFA (lFFA). This observation suggests that race processing can occur effectively even with damage to core face-sensitive regions, challenging the functional significance of race-related activations in the rOFA and lFFA observed in healthy individuals with fMRI. To address this apparent contradiction, we tested PS and age-matched controls during the categorization by race of same- to other-race morphed faces. Our data showed that PS required more visual information to accurately categorize racially ambiguous faces, indicating that intact rOFA and/or lFFA are crucial for extracting fine-grained racial information. These results refine our understanding of the functional roles of these key cortical regions and offer novel insights into the neural mechanisms underlying the perception of face race and prosopagnosia.

The visual perception of race is a process that occurs within the first 200 ms of face presentation (de lissa et al., 2021). Such a fast decisional process implies very early activation of neural pathways sensitive to what must be relatively low-level visual aspects of faces. Of particular relevance to the fields of social and visual neuroscience is the finding that a reliable reaction time advantage is typically observed for the categorization of ‘other’ race faces compared to ‘same’ race faces (relative to the observer). To further clarify the timeline of activation and interplay between neural and behavioural indices of the Other-Race Categorization Advantage (ORCA), we employed a masked priming paradigm in combination with electroencephalography (EEG) to explore the relationship between the two. West Caucasian (WC) and East Asian (EA) faces were presented as masked primes and visible targets while participants performed a race categorization task. Significant facilitation and interference effects were observed for both congruent and incongruent race-primes, respectively, whereas the ORCA was enhanced in both congruent and incongruent conditions. While clear priming effects were observed in the N170 and N250 brain potentials, the N250 exhibited the clearest index of prime congruity. Correlational analyses between reaction times and EEG suggest an early integration of prime and target which has differential effects related to the speed at which same and other race faces are processed. Such effects have implications for a possible separation or divergence of neural pathways activated during explicit race categorization. Additionally, a heightened unconscious perception of other race faces has the potential for profound behavioural effects unrelated to race categorization.

Race is extracted from faces almost instantly and this visual information strongly influences face processing. Healthy observers are more accurate in recognizing same- (SR) relative to other-race (OR) faces (i.e., the Same-Race Recognition Advantage – SRRA), but slower in categorizing by race those faces (i.e., the Other-Race Categorization Advantage – ORCA). Several fMRI studies showed sensitivity to race in the Fusiform Face Area (FFA) and Occipital Face Area (OFA), with some reporting brain-behavior correlations between the activation of the left FFA and the magnitude of both the SRRA and ORCA. However, we recently demonstrated with patient PS, a pure case of acquired prosopagnosia with lesions encompassing the left FFA and the right OFA, that an intact face-cortical network is not necessary to observe the other-race effects. To further clarify the functional role of these face-selective regions in the other-race effects, we asked patient PS, healthy young adults, and age-matched controls to perform a face categorization by race and a face recognition task with the use of more ambiguous stimuli. Specifically, we used continua of morphed SR (i.e., Western Caucasian) and OR (i.e., East Asian) faces created by averaging two face identities. As compared to the controls, PS showed impaired face race discrimination abilities and disrupted SRRA for the most difficult morph level. Our results suggest that while an intact left FFA and/or right OFA are not critical for observing other-race effects, they are required to perform fine-grained race and identity discrimination. These findings refine the knowledge of the functional role of these cortical regions and provide novel insights into the mechanisms related to the neural processing of race in the brain.

Our visual system is very fast and efficient at extracting socially-relevant information from faces we encounter, through central foveal vision as well as in extrafoveal visual fields. Recently, it was shown that race information is extracted very quickly after extrafoveal presentation, leading to reliable saccadic race-categorization responses as early as 200 ms after presentation (de Lissa et al., 2021). While such a fast reaction time suggests that race is extracted in very early stages of perceptual processing, we do not yet have a clear view of the neural activity immediately preceding such overt categorization responses. To this aim, we recorded electroencephalography (EEG) and eye-movements together while participants categorized East Asian (EA) and Western Caucasian (WC) faces, normalized for spatial frequency, spectra and contrast, according to race in a saccadic-choice paradigm. Replicating previous behavioural results and data analyses with Bayes Factors, WC observers were faster to make race-categorization saccades to other- (EA) than to same-race (WC) faces. Surprisingly, EEG recorded during the task revealed higher P1 amplitudes with similar latency in response to same- than other-race faces in occipito-temporal scalp regions. In contrast, later N170 responses to EA and WC faces were not modulated by stimulus race in either amplitude or latency. The early extrafoveal P1 effect in the race-categorization paradigm supports the assertion that race can be extracted in the earlier stages of face perception, and may reflect a mixture of attentional mechanisms interacting with differences in the saliency of race features. These results show how the perception of race may be shaped by experience-driven neural tuning to either emphasize or de-emphasize the relevance of race features. Such very early extrafoveal neural signatures for same-race faces represents a novel twist in the field, significantly feeding the debate on the many visual and social processes related to the extraction of race.

Modern societies are multicultural and multiracial. Race is a visual signal transmitted by faces used for the early categorization of ingroup/outgroup members, strongly modulating their identification and social processing. However, whether the effect of race might also have an influence on action control, particularly on the executive function of action inhibition, has not been investigated yet. To this aim, Western Caucasian observers performed a Stop-Signal Task (SST) where they were instructed to inhibit their actions in response to faces. Stop signals were African-American (AA), Eastern-Asian (EA) and Western-Caucasian (WC) faces normalized for spatial frequency, spectra and contrast. Importantly, race information was not relevant for task execution. The Stop Signal Delay (SSD) was adjusted dynamically for each face category (AA,EA,WC) with the standard adaptive tracking-procedure. Inhibition efficiency was investigated for each race: from inhibition functions, i.e. p(response|stop signal) respectively to SSDs fitted through a Weibull function, we extrapolated critical SSD values (0.5 proportion of inhibitory failures). Moreover, the Stop Signal Reaction Time (SSRT, measure of inhibitory latency) was also measured. Additionally, an Implicit Association Task (IAT) was conducted for each face race to assess both implicit racial attitudes with positive/negative semantics and the speed of face categorization by race. Our data show that WC observers reported better inhibition efficiency for AA faces compared to EA and WC. Additionally, from the IAT we found higher associations with negative semantics for AA compared to both WC and EA faces, as well as the other-race face categorization advantage. However, these two measures did not correlate with action inhibition efficiency. Our data show that other-race faces cannot be considered as a visual and homogeneous social category. The present finding offers new insights and future directions on the many interactions between the visual and social processes related to the visual early extraction of race from faces.

People are typically faster to categorize the race of a face if it belongs to a race different from their own. This Other Race Categorization Advantage (ORCA) is thought to reflect an enhanced sensitivity to the visual race signals of other race faces, leading to faster response times. The current study investigated this sensitivity in a cross-cultural sample of Swiss and Japanese observers with a race categorization task using faces that had been parametrically degraded of visual structure, with normalized luminance and contrast. While Swiss observers exhibited an increasingly strong ORCA in both reaction time and accuracy as the face images were visually degraded up to 20% structural coherence, the Japanese observers manifested this pattern most distinctly when the faces were fully structurally-intact. Critically, for both observer groups, there was a clear accuracy effect at the 20% structural coherence level, indicating that the enhanced sensitivity to other race visual signals persists in significantly degraded stimuli. These results suggest that different cultural groups may rely on and extract distinct types of visual race signals during categorization, which may depend on the available visual information. Nevertheless, heavily degraded stimuli specifically favor the perception of other race faces, indicating that the visual system is tuned by experience and is sensitive to the detection of unfamiliar signals.

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.

The human visual system is very fast and efficient at extracting socially relevant information from faces. Visual studies employing foveated faces have consistently reported faster categorization by race response times for other-race compared with same-race faces. However, in everyday life we typically encounter faces outside the foveated visual field. In study 1, we explored whether and how race is categorized extrafoveally in same- and other-race faces normalized for low-level properties by tracking eye movements of Western Caucasian and East Asian observers in a saccadic response task. The results show that not only are people sensitive to race in faces presented outside of central vision, but the speed advantage in categorizing other-race faces occurs astonishingly quickly in as little as 200 ms. Critically, this visual categorization process was approximately 300 ms faster than the typical button press responses on centrally presented foveated faces. Study 2 investigated the genesis of the extrafoveal saccadic response speed advantage by comparing the influences of the response modality (button presses and saccadic responses), as well as the potential contribution of the impoverished low-spatial frequency spectrum characterizing extrafoveal visual information processing. Button press race categorization was not significantly faster with reconstructed retinal-filtered low spatial frequency faces, regardless of the visual field presentation. The speed of race categorization was significantly boosted only by extrafoveal saccades and not centrally foveated faces. Race is a potent, rapid, and effective visual signal transmitted by faces used for the categorization of ingroup/outgroup members. This fast universal visual categorization can occur outside central vision, igniting a cascade of social processes.

Colour often has emotional connotations, with red associated with negativity and green with positivity. Some suggest that these associations automatically influence the categorization of affective stimuli presented in their context. If so, such effects should occur rapidly, remaining robust under temporal constraints. Here we examined whether these associations influence affective judgments about emotionally ambiguous (neutral or surprised) facial expressions when stimulus presentation duration (Experiment 1) or decision time (Experiment 2) is constrained. Faces appearing on red backgrounds were categorized as negative more than those on green or grey backgrounds, regardless of presentation duration or decision time. Faces on green backgrounds were also categorized as positive more than those on grey backgrounds when decision time was constrained. When incongruent with the expressed emotion, background colour also interfered with affective judgments about emotionally unambiguous faces (Experiment 3). Our findings suggest colour associations rapidly impact valence judgments and potentially operate outside participants' control.

Previous research has shown that visual attention does not always exactly follow gaze direction, leading to the concepts of overt and covert attention. However, it is not yet clear how such covert shifts of visual attention to peripheral regions impact the processing of the targets we directly foveate as they move in our visual field. The current study utilised the co-registration of eye-position and EEG recordings while participants tracked moving targets that were embedded with a 30 Hz frequency tag in a Steady State Visually Evoked Potentials (SSVEP) paradigm. When the task required attention to be divided between the moving target (overt attention) and a peripheral region where a second target might appear (covert attention), the SSVEPs elicited by the tracked target at the 30 Hz frequency band were significantly, but transiently, lower than when participants did not have to covertly monitor for a second target. Our findings suggest that neural responses of overt attention are only briefly reduced when attention is divided between covert and overt areas. This neural evidence is in line with theoretical accounts describing attention as a pool of finite resources, such as the perceptual load theory. Altogether, these results have practical implications for many real-world situations where covert shifts of attention may discretely reduce visual processing of objects even when they are directly being tracked with the eyes.

In the current days, virtual reality (VR) has become a widespread, easily accessible technology. The intrinsic advantage of generating experiments in fully controlled, realistic and engaging scenarios opens up endless possibilities in modern eye-movement research and in visual sciences. However, the readiness of this technology clashes with the unavailability of any user-friendly tool to analyze the highly multidimensional VR eye-movement data. In our previous work with iMap4 (Lao et al., 2017), we provided the possibility to turn 2D sparse fixation data (x, y eye-movement coordinates weighted by the fixation duration) in continuous statistical maps, and isolate significant differences between groups and conditions with linear mixed modeling. Here, we developed iMap4D, which allows to perform the same robust data-driven statistical evaluation as iMap4, while also handling two further VR dimensions (the z-coordinate and time), with smooth pursuits on moving objects also included in the map. To estimate average individual fixation maps on the model mesh, for every condition we perform a space convolution between the sparse fixation points and a 3D Gaussian kernel. The size of the kernel is scaled to account for objects’ apparent size due to their position in the 3D space. We then consider the continuous hypersur-face resulting from the statistical fixation intensity on each vertices of the mesh. Similar to iMap4, we apply for each vertex a univariate linear mixed model with subject as a random effect. All the possible linear contrasts can be performed, which statistical significance can be assessed by a spatial cluster test based on bootstrapping. To the best of our knowledge, iMap4D is the first free MATLAB open source toolbox for the statistical fixation mapping of 4D eye-movement data, and we believe that this toolbox could pave the way in boosting the number of vision science studies exploiting the ground-breaking VR technologies.

In the last 20 years, there has been increasing interest in studying visual attentional processes under more natural conditions. In the present study, we propose to determine the critical age at which children show similar to adult performance and attentional control in a visually guided task; in a naturalistic dynamic and socially relevant context: road crossing. We monitored visual exploration and crossing decisions in adults and children aged between 5 and 15 while they watched road traffic videos containing a range of traffic densities with or without pedestrians. 5–10 year old (y/o) children showed less systematic gaze patterns. More specifically, adults and 11–15 y/o children look mainly at the vehicles’ appearing point, which is an optimal location to sample diagnostic information for the task. In contrast, 5–10 y/os look more at socially relevant stimuli and attend to moving vehicles further down the trajectory when the traffic density is high. Critically, 5-10 y/o children also make an increased number of crossing decisions compared to 11–15 y/os and adults. Our findings reveal a critical shift around 10 y/o in attentional control and crossing decisions in a road crossing task.

The N170 ERP peak has been found to be consistently larger in response to the presentation of faces than to other objects, yet it is not clear whether this face-sensitive N170 is also elicited during fixations made subsequent to the initial presentation. To investigate this question, the current study utilised Event and Fixation-Related Potentials in two experiments, time-locking brain potentials to the presentation of faces and objects (watches) images in participants? peripheral vision, and to their first fixations on the images. Experiment 1 found that a face-sensitive N170 was elicited by the onset of images but not by a subsequent fixation on the images, and that face inversion did not modulate N170 beyond presentation. Experiment 2 found that disrupting the structure of the peripheral preview (phase-scrambling) led to a face-sensitive N170 at fixation onsets on the intact-images. Interestingly, N170 amplitudes for both faces and objects were significantly enhanced after the peripheral preview was phase-scrambled, suggesting that the N170 in part reflects a category-detection process that is elicited once when an image structure is viewed. These results indicate that neural processing during fixations will be significantly modulated when they are immediately preceded by peripheral previews, and is not specific to faces.

Recent studies link meditation expertise with enhanced low-level attention, measured through auditory eventrelated potentials (ERPs). In this study, we tested the reliability and validity of a recent finding that the N1 ERP in first-time meditators is smaller during meditation than non-meditation – an effect not present in long-term meditators. In the first experiment, we replicated the finding in first-time meditators. In two subsequent experiments, we discovered that this finding was not due to stimulus-related instructions, but was explained by an effect of the order of conditions. Extended exposure to the same tones has been linked with N1 decrement in other studies, and may explain N1 decrement across our two conditions. We give examples of existing meditation and ERP studies that may include similar condition order effects. The role of condition order among first-time meditators in this study indicates the importance of counterbalancing meditation and non-mediation conditions in meditation studies that use event-related potentials.

270,000 pedestrians die of road traffic accidents and millions are injured each year. Children and older adults are overrepresented in these groups. However, little is known about the perceptual processes used by vulnerable pedestrians. To investigate perceptual processes involved in road-crossing, we monitored visual exploration and road-crossing decisions in children from 5 to 15 years-old, adults aged 18-25, and older adults aged 60 or above while they watched road-traffic videos containing distractors (people) and a range of traffic densities. Data-driven clustering approaches found a critical age of under 10 at which children are more likely to cross the road in short gaps. Interestingly, decision biases under 10 were associated with visual biases. While the maximum gaze distributions were at the start of the vehicle's' trajectory for all age groups, gaze similarity matrices (GSMs) revealed more varied gaze patterns across trials for children under 10 than for adolescents, young and older adults. iMap4 (Lao et al., 2017) showed that the variability in gaze patterns for children under 10 can be explained by gaze towards distractors irrelevant to the road-crossing task (human beings) and towards approaching vehicles when the traffic density is high. For all age groups oculomotor characteristics are impacted by distractors and traffic density, suggesting attentional capture. We propose that adolescents, younger and older adults are able to inhibit gaze orientation towards irrelevant stimuli; thus maintaining their gaze to the optimal location for the task. In contrast, children under 10 are less able to inhibit orientation towards irrelevant stimuli thus reducing access to diagnostic information, impacting their decisions. Older adults showed similar general gaze patterns to younger adults except for specificities when using fine-grained temporal analyses based on automatic image processing. Older adults' vulnerability is discussed in terms of delays in attention allocation, decisions, and decline in executive functioning. Meeting abstract presented at VSS 2018