Other-race Faces Research Articles

Tuning of face expertise with a racially heterogeneous face-diet

ABSTRACT The contact hypothesis posits that a racially-homogenous face-diet, in part, accounts for the other-race effect (ORE)—a difficulty in recognizing other-race faces. This account does not specify whether racial homogeneity of face exposure is necessary to achieving native-level expertise for own-race faces. Here we propose three new models that complement and extend the contact hypothesis: the experience-limited, the capacity-limited, and the enhancement hypotheses, each with differing predictions in the context of abundant exposure to multiple race categories. The experience-limited account proposes that greater experience always leads to better performance. The alternative capacity-limited account allows for detrimental effects of racially-heterogeneous exposure. The enhancement account predicts heterogeneity of exposure confers added benefits. In two experiments we examined face recognition in a group with sustained lifetime exposure to Caucasian and East Asian faces (dual exposure) in comparison to two mono exposure groups. Dual-exposure individuals showed native-like performance on the face recognition tasks for both Caucasian and East Asian faces. We found no evidence of a detrimental or an enhancing effect of racially-heterogeneous face exposure. Overall, our results support the experience-limited account of face expertise. We conclude that a racially homogeneous face-diet is not necessary to achieve native-level face expertise.

Effects of subjective similarity and culture on ensemble perception of faces.

It is well established that ensemble coding is regulated by physical similarity and variance in a set of stimuli. For example, observers are more accurate at judging the mean size of objects in a set if the overall size variance in the set is small. However, sometimes similarity among set members can be purely subjective. For example, faces from another race tend to look more similar than faces from one's own race. Very little is known about whether such subjective similarity also regulates ensemble coding in the same manner as objective similarity. To investigate this question, we had British and Chinese participants view sets of four faces that were of either own-race or other-race, own-gender or other-gender. After viewing each set the task was to judge whether a test face was presented in the set. Our results showed that, as demonstrated in prior research, participants often mistook a morphed set average to be a member of the set. Critically, this tendency to average a face set was not stronger for other-race faces. Hence contrary to objective similarity, subjectively perceived similarity in the other-race faces does not facilitate ensemble coding. The results in our British group also replicated de Fockert and Gautrey's (Psychonomic Bulletin & Review 20 (3), 468-473, 2013) own-gender effect, where observers showed more averaging for own-gender faces. However, our Chinese subjects displayed the same level of averaging for both genders. This suggests a cultural difference in ensemble coding, where the own-gender bias may be overridden by a stronger tendency to employ ensemble coding in Chinese participants.

The study of the differences between low-functioning autistic children and typically developing children in the processing of the own-race and other-race faces by the machine learning approach

ObjectiveAutism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder which affects the developmental trajectory in several behavioral domains, including impairments of social communication and stereotyped behavior. Unlike typically developing children who can successfully obtain the detailed facial information to decode the mental status with ease, autistic children cannot infer instant feelings and thoughts of other people due to their abnormal face processing. In the present study, we tested the other-race face, the own-race strange face and the own-race familiar face as stimuli material to explore whether ASD children would display different face fixation patterns for the different types of face compared to TD children. We used a machine learning approach based on eye tracking data to classify autistic children and TD children. MethodsSeventy-seven low-functioning autistic children and eighty typically developing children were recruited. They were required to watch a series face photos in a random order. According to the coordinate frequency distribution, the K-means clustering algorithm divided the image into 64 Area Of Interest (AOI) and selected the features using the minimal redundancy and maximal relevance (mRMR) algorithm. The Support Vector Machine (SVM) was used to classify to determine whether the scan patterns of different faces can be used to identify ASD, and to evaluate classification models from both accuracy and reliability. ResultsThe results showed that the maximum classification accuracy was 72.50% (AUC = 0.77) when 32 of the 64 features of unfamiliar other-race faces were selected; the maximum classification accuracy was 70.63% (AUC = 0.76) when 18 features of own-race strange faces were selected; the maximum classification accuracy was 78.33% (AUC = 0.84) when 48 features of own-race familiar faces were selected; The classification accuracy of combining three types of faces reached a maximum of 84.17% and AUC = 0.89 when 120 features were selected. ConclusionsThere are some differences between low-functioning autistic children and typically developing children in the processing of the own-race and other-race faces by the machine learning approach, which might be a useful tool for classifying low-functioning autistic children and TD children.

Implicit race attitudes modulate visual information extraction for trustworthiness judgments.

Black people are still considered to be one of the most stigmatized groups and have to face multiple prejudices that undermine their well-being. Assumptions and beliefs about other racial groups are quite pervasive and have been shown to impact basic social tasks such as face processing. For example, individuals with high racial prejudice conceptualize other-race faces as less trustworthy and more criminal. However, it is unknown if implicit racial bias could modulate even low-level perceptual mechanisms such as spatial frequency (SF) extraction when judging the level of trustworthiness of other-race faces. The present study showed that although similar facial features are used to judge the trustworthiness of White and Black faces, own-race faces are processed in lower SF (i.e. coarse information such as the contour of the face and blurred shapes as opposed to high SF representing fine-grained information such as eyelashes or fine wrinkles). This pattern was modulated by implicit race biases: higher implicit biases are associated with a significantly higher reliance on low SF with White than with Black faces.

Neural dynamics of pain expression processing: Alpha-band synchronization to same-race pain but desynchronization to other-race pain

Both electroencephalography and functional magnetic resonance imaging studies have revealed enhanced neural responses to perceived pain in same-race than other-race individuals. However, it remains unclear how neural responses in the sensorimotor, cognitive, and affective subsystems vary dynamically in the first few hundreds of milliseconds to generate racial ingroup favoritism in empathy for pain. We recorded magnetoencephalography signals to pain and neutral expressions of Asian and white faces from Chinese adults during judgments of racial identity of each face. We found that pain compared to neutral expressions of same-race faces induced early increased alpha oscillations in the precuneus/parietal cortices followed by increased alpha-band oscillations in the left anterior insula and temporoparietal junction. Pain compared to neutral expressions of other-race faces, however, induced early suppression of alpha-band oscillations in the bilateral sensorimotor cortices and left insular cortex. Moreover, decreased functional connectivity between the left sensorimotor cortex and left anterior insula predicted reduced subjective feelings of other-race suffering. Our results unraveled distinct patterns of modulations of neural dynamics of sensorimotor, affective, and cognitive components of empathy by interracial relationships between an observer and a target person, which provide possible brain mechanisms for understanding racial ingroup favoritism in social behavior.

Cultural Differences in the Time Course of Configural and Featural Processing for Own-race Faces

Previous research suggests that East Asians pay more attention than Caucasian Westerners to configural information in faces, while the latter group pays more attention to featural information. However, it is unclear whether this cultural variation in attention produces a different time course of the processing bias for configural and featural information. This was examined using event-related potentials in a spatial attention paradigm. Chinese and Westerners were instructed to attend to the locations of two face images or houses. Although the race-related difference was absent in behavioral performance and N170 component, Chinese participants exhibited a configural processing bias on P1 component in the case of both own- and other-race faces and a featural processing bias on P2 component for own-race faces. In contrast, Westerners exhibited a featural processing bias for own-race faces and a configural processing bias for other-race faces on P1 component, whereas a configural processing bias was observed on P2 component for both own- and other-race faces. These results demonstrate that there are important differences between East Asians and Westerners in their relative preferences for configural versus featural processing of own-race faces, but not other-race faces. The relative roles of configural and featural information processing for faces are thus dependent on both who is looking (the culture or race of the observer) and what they are looking at (the race of the face): Easterners enjoy an early global/configural processing bias and a late local/featural processing bias for own-race faces, while Westerners benefit from an early local/featural processing bias and a late global/configural processing bias for own-race faces; both of the groups have an early and late global/configural processing bias for other-race faces.

A developmental investigation of the other-race categorization advantage in a multiracial population: Contrasting social categorization and perceptual expertise accounts

Most prior studies of the other-race categorization advantage have been conducted in predominantly monoracial societies. This limitation has left open the question of whether tendencies to more rapidly and accurately categorize other-race faces reflect social categorization (own-race vs. other-race) or perceptual expertise (frequent exposure vs. infrequent exposure). To address this question, we tested Malay and Malaysian Chinese children (9- and 10-year-olds) and adults on (a) own-race faces (i.e., Malay faces for Malay participants and Chinese faces for Malaysian Chinese participants), (b) high-frequency other-race faces (i.e., Chinese faces for Malay participants and Malay faces for Malaysian Chinese participants), and (c) low-frequency other-race faces (i.e., Caucasian faces). Whereas the other-race categorization advantage was in evidence in the accuracy data of Malay adults, other aspects of performance were supportive of either the social categorization or perceptual expertise accounts and were dependent on the race (Malay vs. Chinese) or age (child vs. adult) of the participants. Of particular significance is the finding that Malaysian Chinese children and adults categorized own-race Chinese faces more rapidly than high-frequency other-race Malay faces. Thus, in accord with a perceptual expertise account, the other-race categorization advantage seems to be more an advantage for racial categories of lesser experience regardless of whether these face categories are own-race or other-race.

Ensemble coding of facial identity is not refined by experience: Evidence from other-race and inverted faces.

The ability to recognize identity despite within-person variability in appearance is likely a face-specific skill and shaped by experience. Ensemble coding - the automatic extraction of the average of a stimulus array - has been proposed as a mechanism underlying face learning (allowing one to recognize novel instances of a newly learned face). We investigated whether ensemble encoding, like face learning and recognition, is refined by experience by testing participants with upright own-race faces and two categories of faces with which they lacked experience: other-race faces (Experiment 1) and inverted faces (Experiment 2). Participants viewed four images of an unfamiliar identity and then were asked whether a test image of that same identity had been in the study array. Each test image was a matching exemplar (from the array), matching average (the average of the images in the array), non-matching exemplar (a novel image of the same identity), or non-matching average (an average of four different images of the same identity). Adults showed comparable ensemble coding for all three categories (i.e., reported that matching averages had been present more than non-matching averages), providing evidence that this early stage of face learning is not shaped by face-specific experience.

Infants' Gaze Patterns for Same-Race and Other-Race Faces, and the Other-Race Effect.

The other-race effect (ORE) can be described as difficulties in discriminating between faces of ethnicities other than one’s own, and can already be observed at approximately 9 months of age. Recent studies also showed that infants visually explore same-and other-race faces differently. However, it is still unclear whether infants’ looking behavior for same- and other-race faces is related to their face discrimination abilities. To investigate this question we conducted a habituation–dishabituation experiment to examine Caucasian 9-month-old infants’ gaze behavior, and their discrimination of same- and other-race faces, using eye-tracking measurements. We found that infants looked longer at the eyes of same-race faces over the course of habituation, as compared to other-race faces. After habituation, infants demonstrated a clear other-race effect by successfully discriminating between same-race faces, but not other-race faces. Importantly, the infants’ ability to discriminate between same-race faces significantly correlated with their fixation time towards the eyes of same-race faces during habituation. Thus, our findings suggest that for infants old enough to begin exhibiting the ORE, gaze behavior during habituation is related to their ability to differentiate among same-race faces, compared to other-race faces.

Exemplar learning reveals the representational origins of expert category perception

Irrespective of whether one has substantial perceptual expertise for a class of stimuli, an observer invariably encounters novel exemplars from this class. To understand how novel exemplars are represented, we examined the extent to which previous experience with a category constrains the acquisition and nature of representation of subsequent exemplars from that category. Participants completed a perceptual training paradigm with either novel other-race faces (category of experience) or novel computer-generated objects (YUFOs) that included pairwise similarity ratings at the beginning, middle, and end of training, and a 20-d visual search training task on a subset of category exemplars. Analyses of pairwise similarity ratings revealed multiple dissociations between the representational spaces for those learning faces and those learning YUFOs. First, representational distance changes were more selective for faces than YUFOs; trained faces exhibited greater magnitude in representational distance change relative to untrained faces, whereas this trained-untrained distance change was much smaller for YUFOs. Second, there was a difference in where the representational distance changes were observed; for faces, representations that were closer together before training exhibited a greater distance change relative to those that were farther apart before training. For YUFOs, however, the distance changes occurred more uniformly across representational space. Last, there was a decrease in dimensionality of the representational space after training on YUFOs, but not after training on faces. Together, these findings demonstrate how previous category experience governs representational patterns of exemplar learning as well as the underlying dimensionality of the representational space.

The Own-Race Bias for Face Recognition in a Multiracial Society.

The own-race bias (ORB) is a reliable phenomenon across cultural and racial groups where unfamiliar faces from other races are usually remembered more poorly than own-race faces (Meissner and Brigham, 2001). By adopting a yes–no recognition paradigm, we found that ORB was pronounced across race groups (Malaysian–Malay, Malaysian–Chinese, Malaysian–Indian, and Western–Caucasian) when faces were presented with only internal features (Experiment 1), implying that growing up in a profoundly multiracial society does not necessarily eliminate ORB. Using a procedure identical to Experiment 1, we observed a significantly greater increment in recognition performance for other-race faces than for own-race faces when the external features (e.g. facial contour and hairline) were presented along with the internal features (Experiment 2)—this abolished ORB. Contrary to assumptions based on the contact hypothesis, participants’ self-reported amount of interracial contact on a social contact questionnaire did not significantly predict the magnitude of ORB. Overall, our findings suggest that the level of exposure to other-race faces accounts for only a small part of ORB. In addition, the present results also support the notion that different neural mechanisms may be involved in processing own- and other-race faces, with internal features of own-race faces being processed more effectively, whereas external features dominate representations of other-race faces.

Positive intergroup contact modulates fusiform gyrus activity to black and white faces

In this study, we investigated the effect of intergroup contact on processing of own- and other-race faces using functional Magnetic Resonance Imaging (fMRI). Previous studies have shown a neural own-race effect with greater BOLD response to own race compared to other race faces. In our study, white participants completed a social-categorization task and an individuation task while viewing the faces of both black and white strangers after having answered questions about their previous experiences with black people. We found that positive contact modulated BOLD activity in the right fusiform gyrus (rFG) and left inferior occipital gyrus (lIOC), regions associated with face processing. Within these regions, higher positive contact was associated with higher activity when processing black, compared to white faces during the social categorisation task. We also found that in both regions a greater amount of individuating experience with black people was associated with greater activation for black vs. white faces in the individuation task. Quantity of contact, implicit racial bias and negatively valenced contact showed no effects. Our findings suggest that positive contact and individuating experience directly modulate processing of out-group faces in the visual cortex, and illustrate that contact quality rather than mere familiarity is an important factor in reducing the own race face effect.

Caucasian Infants' Attentional Orienting to Own- and Other-Race Faces.

Infants show preferential attention toward faces and detect faces embedded within complex naturalistic scenes. Newborn infants are insensitive to race, but rapidly develop differential processing of own- and other-race faces. In the present study, we investigated the development of attentional orienting toward own- and other-race faces embedded within naturalistic scenes. Infants aged six-, nine- and twelve-months did not show differences in the speed of orienting to own- and other race faces, but other-race faces held infants’ visual attention for longer. We also found a clear developmental progression in attentional capture and holding, with older infants orienting to faces faster and fixating them for longer. Results are interpreted within the context of the two-process model of face processing.

Emotional expressions reinstate recognition of other-race faces in infants following perceptual narrowing.

Perceptual narrowing occurs in human infants for other-race faces. A paired-comparison task measuring infant looking time was used to investigate the hypothesis that adding emotional expressiveness to other-race faces would help infants break through narrowing and reinstate other-race face recognition. Experiment 1 demonstrated narrowing for White infants viewing neutral Asian faces: whereas 3-month-olds differentiated Asian faces, 6-month-olds did not. Experiment 2 showed that White 6-month-olds differentiated the same Asian faces depicted with angry or happy expressions. Experiments 3 and 4 yielded comparable results for 6- and 9-month-olds tested with Black faces (i.e., narrowing with neutral faces, reinstatement of sensitivity when the faces were presented with emotion). Experiment 5 showed that White 6-month-olds did not differentiate inverted angry or happy Asian faces, and that White 9-month-olds did not differentiate inverted angry or happy Black faces. Looking time during familiarization did not differ for upright neutral and emotional faces, indicating that the expressions did not yield more salient stimuli. Also, consistent with the inversion findings, analyses of the low-level image properties as well as equivalent pairwise similarity ratings obtained from White adults for the neutral and emotional faces indicated that the expressions did not simply create more discriminable stimuli. Without support for the lower-level accounts, we discuss the possibility that the infants processed the communicative intent of the expressions. Because angry faces pose threat and happy faces invite affiliation, expression may create motivation to individuate. Overall, the data suggest that early perceptual-social linkage in face representation can arise via a social-to-perceptual pathway. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Other-Race and Other-Species Effect during a Sex Categorization Task: An Eye Tracker Study.

Sex categorization from faces is a crucial ability for humans and non-human primates for various social and cognitive processes. In the current study, we performed two eye tracking experiments to examine the gaze behavior of participants during a sex categorization task in which participants categorize face pictures from their own-race (Caucasian), other-race (Asian) and other-species (chimpanzee). In experiment 1, we presented the faces in an upright position to 16 participants, and found a strong other-race and other-species effect. In experiment 2, the same faces were shown to 24 naïve participants in an upside-down (inverted) position, which showed that, although the other-species effect was intact, other-race effect disappeared. Moreover, eye-tracking analysis revealed that in the upright position, the eye region was the first and most widely viewed area for all face categories. However, during upside-down viewing, participants’ attention directed more towards the eye region of the own-race and own-species faces, whereas the nose received more attention in other-race and other-species faces. Overall results suggest that other-race faces were processed less holistically compared to own-race faces and this could affect both participants’ behavioral performance and gaze behavior during sex categorization. Finally, gaze data suggests that the gaze of participants shifts from the eye to the nose region with decreased racial and species-based familiarity.

Supplemental Material for Emotional Expressions Reinstate Recognition of Other-Race Faces in Infants Following Perceptual Narrowing

Supplemental Material for Emotional Expressions Reinstate Recognition of Other-Race Faces in Infants Following Perceptual Narrowing

A Memory Computational Basis for the Other-Race Effect

People often recognize and remember faces of individuals within their own race more easily than those of other races. While behavioral research has long suggested that the Other-Race Effect (ORE) is due to extensive experience with one’s own race group, the neural mechanisms underlying the effect have remained elusive. Predominant theories of the ORE have argued that the effect is mainly caused by processing disparities between same and other-race faces during early stages of perceptual encoding. Our findings support an alternative view that the ORE is additionally shaped by mnemonic processing mechanisms beyond perception and attention. Using a “pattern separation” paradigm based on computational models of episodic memory, we report evidence that the ORE may be driven by differences in successful memory discrimination across races as a function of degree of interference or overlap between face stimuli. In contrast, there were no ORE-related differences on a comparable match-to-sample task with no long-term memory load, suggesting that the effect is not simply attributable to visual and attentional processes. These findings suggest that the ORE may emerge in part due to “tuned” memory mechanisms that may enhance same-race, at the expense of other-race face detection.

Neural dynamics of racial categorization predicts racial bias in face recognition and altruism.

The classification of individuals into different racial groups provides a precondition for racial bias in cognition and behaviour, but how the brain enables spontaneous racial categorization is not fully understood. Here using multimodal brain imaging measures, including electroencephalography, functional magnetic resonance imaging and magnetoencephalography, we probe the neural dynamics of racial categorization by quantifying the repetition suppression of neural responses to faces of different individuals of each racial group (that is, Asian, black or white). We show that categorization of other-race faces engages early two-stage dynamic activities in neural networks consisting of multiple interactive brain regions. Categorization of same-race faces, however, recruits a different and simple network in a later time window. Dynamic neural activities involved in racial categorization predict racial biases in face recognition and altruistic intention. These results suggest that there are distinct neural dynamics by which the brain sorts people into different racial groups as a social ground for cognition and action.

Learning own- and other-race facial identities: Testing implicit recognition with event-related brain potentials

Exposure to varying images of the same person can encourage the formation of a representation that is sufficiently robust to allow recognition of previously unseen images of this person. While behavioural work suggests that face identity learning is harder for other-race faces, the present experiment investigated the neural correlates underlying own- and other-race face learning. Participants sorted own- and other-race identities into separate identity clusters and were further familiarised with these identities in a matching task. Subsequently, we compared event-related brain potentials (ERPs) in an implicit recognition (butterfly detection) task for learnt and previously unseen identities. We observed better sorting and matching for own- than other-race identities, and behavioural learning effects were restricted to own-race identities. Similarly, the N170 ERP component showed clear learning effects for own-race faces only. The N250, a component more closely associated with face learning was more negative for learnt than novel identities. ERP findings thus suggests a processing advantage for own-race identities at an early perceptual level whereas later correlates of identity learning were unaffected by ethnicity. These results suggest learning advantages for own-race identities, which underscores the importance of perceptual expertise in the own-race bias.

Recognition of faces despite changes in appearance: How similarity and race affect our tolerance for within-person variability

Successful face recognition involves the ability to generalize recognition across within-person variability in appearance (e.g., lighting, expressions). Research shows we are less tolerant of within-person variability in unfamiliar faces1 and particularly for other-race faces2,3. Less is known about how face similarity influences adults’ ability to build stable face representations that are tolerant to variability in appearance, and whether this process differs for own- versus other-race faces. We applied a sorting task1 to assess people’s ability to recognize faces across variability. White and East Asian adults (currently n = 35) were handed a stack of 40 photographs of two identities and were asked to sort them into different piles based on identity, such that each pile contained all photos of the same identity. Adults were not told the correct number of identities and were randomly assigned to sort either own- or other-race faces and pairs that either looked similar or dissimilar. We analyzed the number of perceived identities (i.e., number of piles created) and intrusion errors (i.e., different person/same pile). Preliminary analysis based on data from the White participants (n = 27) indicated no significant main effects or interaction between face race and similarity on the number of perceived identities (ps > .46; Figure 1). However, we found a significant interaction between face race and similarity on intrusion errors (F(1) = 4.78, p = 0.039, η2 = .17; Figure 2). Consistent with past research4, this finding suggests that the ability to discriminate between identities is impaired for other-race compared to own-race faces particularly when the faces look extremely similar (i.e., densely clustered in face space5). People’s ability to form stable facial representations might be influenced by the way in which own- and other-race faces are mentally represented in face space, making this research theoretically important.