Cross-cultural differences and similarities underlying other-race effects for facial identity and expression

Implicit bias and experience influence overall but not relative trustworthiness judgment of other-race faces

Impressions of trustworthiness are formed quickly from faces. To what extent are these impressions shared among observers of the same or different races? Although high consensus of trustworthiness evaluation has been consistently reported, recent studies suggested substantial individual differences. For instance, negative implicit racial bias and low contact experience towards individuals of the other race have been shown to be related to low trustworthiness judgments for other-race faces. This pre-registered study further examined the effects of implicit social bias and experience on trustworthiness judgments of other-race faces. A relatively large sample of White (N = 338) and Black (N = 299) participants completed three tasks: a trustworthiness rating task of faces, a race implicit association test, and a questionnaire of experience. Each participant rated trustworthiness of 100 White faces and 100 Black faces. We found that the overall trustworthiness ratings for other-race faces were influenced by both implicit bias and experience with individuals of the other-race. Nonetheless, when comparing to the own-race baseline ratings, high correlations were observed for the relative differences in trustworthiness ratings of other-race faces for participants with varied levels of implicit bias and experience. These results suggest differential impact of social concepts (e.g., implicit bias, experience) vs. instinct (e.g., decision of approach-vs-avoid) on trustworthiness impressions, as revealed by overall vs. relative ratings on other-race faces.

No evidence for an other-race effect in dominance and trustworthy judgements from faces

A variety of evidence shows that social categorization of people based on their race can lead to stereotypical judgements and prejudicial behaviour. Here, we explore the extent to which trait judgements of faces are influenced by race. To address this issue, we measured the reliability of first impressions for own-race and other-race faces in Asian and White participants. Participants viewed pairs of faces and were asked to indicate which of the two faces was more dominant or which of the two faces was more trustworthy. We measured the consistency (or reliability) of these judgements across participants for own-race and other-races faces. We found that judgements of dominance or trustworthiness showed similar levels of reliability for own-race and other-race faces. Moreover, an item analysis showed that the judgements on individual trials were very similar across participants from different races. Next, participants made overall ratings of dominance and trustworthiness from own-race and other-race faces. Again, we found that there was no evidence for an ORE. Together, these results provide a new approach to measuring trait judgements of faces and show that in these conditions there is no ORE for the perception of dominance and trustworthiness.

Analysis of Facial Occlusion Challenge in Thermal Images for Human Affective State Recognition

Several studies have been conducted using both visual and thermal facial images to identify human affective states. Despite the advantages of thermal facial images in recognizing spontaneous human affects, few studies have focused on facial occlusion challenges in thermal images, particularly eyeglasses and facial hair occlusion. As a result, three classification models are proposed in this paper to address the problem of thermal occlusion in facial images, with six basic spontaneous emotions being classified. The first proposed model in this paper is based on six main facial regions, including the forehead, tip of the nose, cheeks, mouth, and chin. The second model deconstructs the six main facial regions into multiple subregions to investigate the efficacy of subregions in recognizing the human affective state. The third proposed model in this paper uses selected facial subregions, free of eyeglasses and facial hair (beard, mustaches). Nine statistical features on apex and onset thermal images are implemented. Furthermore, four feature selection techniques with two classification algorithms are proposed for a further investigation. According to the comparative analysis presented in this paper, the results obtained from the three proposed modalities were promising and comparable to those of other studies.

Event-related brain potential correlates of the other-race effect: A review

People are better at remembering own-race relative to other-race faces. Here, we review event-related brain potential (ERP) correlates of this so-called other-'race' effect (ORE) by discussing three critical aspects that characterize the neural signature of this phenomenon. First, difficulties with other-race faces initially emerge during perceptual processing, which is indexed by an increased N170. Second, as evidenced by 'difference due to subsequent memory' effects, more effortful processing of other-race faces is needed for successful encoding into long-term memory. Third, ERP old/new effects reveal that a stronger engagement of processing resources is also required for successful retrieval of other-race faces from memory. The ERP evidence available to date thus suggests widespread ethnicity-related modulations during both perceptual and mnemonic processing stages. We further discuss how findings from the ORE compared with potentially related memory biases (e.g. other-gender or other-age effects) and how ERP findings inform the ongoing debate regarding the mechanisms underlying the ORE. Finally, we outline open questions and potential future directions with an emphasis on using multiple, ecologically more valid 'ambient' images for each face to assess the ORE in paradigms that capture identity rather than image recognition.

Effects of Emotional Expression on Face Recognition May Be Accounted for by Image Similarity

We examined the degree to which differences in face recognition rates across emotional expression conditions varied concomitantly with differences in mean objective image similarity. Effects of emotional expression on face recognition performance were measured via an old/new recognition paradigm in which stimuli at both learning and testing had happy, neutral, and angry expressions. Results showed an advantage for faces learned with neutral expressions, as well as for angry faces at testing. Performance data was compared to three quantitative image-similarity indices. Findings showed that mean human performance was strongly correlated with mean image similarity, suggesting that the former may be at least partly explained by the latter. Our findings sound a cautionary note regarding the necessity of considering low-level stimulus properties as explanations for findings that otherwise may be prematurely attributed to higher order phenomena such as attention or emotional arousal.

The Role of Racial and Developmental Experience on Emotional Adaptive Coding in Autism Spectrum Disorder

Sensitivity to emotional face aids in rapid detection and evaluation of others, such that by school-age, children and youth exhibit adult-like patterns when the prolonged viewing of an emotional face distorts the perception of a subsequent face. However, the developmental considerations of this phenomenon (known as emotional adaptive coding) are unclear given ongoing maturational and experiential changes, including the influence of own-race experiences or the lack of face expertise, as is evident in autism spectrum disorder (ASD). This study addressed whether emotional adaptive coding is sensitive to factors of face perception expertise, specifically self-race and developmental experience, in adults (age 19-28 years) and youth (age 10-16 years). Emotional adaptive coding was not influenced by race expertise (i.e., other versus same race identity) in White and Asian adults. Emotional adaptation coding during childhood and adolescence is consistent with adults, though youth with ASD exhibited stronger adaptor after-effects in response to other-race faces, relative to TD youth and adults. By extending prior work to examine the integration of race and emotional adaptive coding in ASD, we discovered that the strength of response in ASD is atypical when viewing other-race faces, which clarifies the role of racial and facial experience on emotional face adaption.

Perceptual integration and the composite face effect

The composite face paradigm is widely used to investigate holistic perception of faces. In the paradigm, parts from different faces (usually the top and bottom halves) are recombined. The principal criterion for holistic perception is that responses involving the component parts of composites in which the parts are aligned into a face-like configuration are disrupted compared with the same parts in a misaligned (not face-like) format. This is often taken as evidence that seeing a whole face in the aligned condition interferes with perceiving its separate parts, but the extent to which the effect is perceptually driven remains unclear. We used salient perceptual categories of gender (male or female) and race (Asian or Caucasian appearance) to create composite stimuli from parts of faces that varied orthogonally on these characteristics. In Experiment 1, participants categorised the gender of the parts of aligned composite and misaligned images created from parts with the same (congruent) or different (incongruent) gender and the same (congruent) or different (incongruent) race. In Experiment 2, the same stimuli were used but the task changed to categorising race. In both experiments, there was a strong influence of the task-relevant manipulation on the composite effect, with slower responses to aligned stimuli with incongruent gender in Experiment 1 and incongruent race in Experiment 2. In contrast, the task-irrelevant variable (race in Experiment 1, gender in Experiment 2) did not exert much influence on the composite effect in either experiment. These findings show that although holistic integration of salient visual properties makes a strong contribution to the composite face effect, it clearly also involves targeted processing of an attended visual characteristic.

Effects of REM sleep during a daytime nap on emotional perception in individuals with and without depression

BACKGROUND

It has been theoretically proposed that alteration in sleep physiology may contribute to the development of biased emotional processing featured in depression. The current study investigated the role of sleep and especially REM in modulating perception of emotional faces in depressed versus non-depressed individuals using a napping paradigm.

METHODS

Forty-six individuals with major depressive disorder and 66 age- and education-matched healthy controls completed an emotional face perception task before and after random assignment to one of the three intention-to-treat (ITT) conditions, namely 30-min-nap, 90-min-nap and wake. To delineate the effects of REM, as-treated (30-min-nap, 90-min-REM-nap, 90-min-noREM-nap and wake) analyses were also conducted.

RESULTS

Repeated measures multivariate analysis of covariance (MANCOVA) showed a significant Time *Group *Condition interaction on angry faces for both analyses of ITT (p = .017) and AT (p = .027). Pairwise comparison with Bonferroni corrections revealed a significant increase in the intensity rating of angry faces only after 90-min-REM-nap in the depressed group. Correlational analyses convergingly showed that the increase of intensity rating of angry faces was associated with the proportion of REM sleep in the depressed group, p = .035.

LIMITATIONS

The observed effect of REM sleep during daytime napping may not represent the effect of nighttime REM sleep in depression.

CONCLUSIONS

We provide the first evidence of the association of daytime sleep, particularly REM sleep, with a more negative perception of angry faces exclusively in individuals with depression. The differentiated impact of sleep observed may contribute to the development of altered emotional processing in depression.

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.

Learning own- and other-race facial identities from natural variability

Exposure to multiple varying face images of the same person encourages the formation of identity representations which are sufficiently robust to allow subsequent recognition from new, never-before seen images. While recent studies suggest that identity information is initially harder to perceive in images of other- relative to own-race identities, it remains unclear whether these difficulties propagate to face learning, that is, to the formation of robust face representations. We report two experiments in which Caucasian and East Asian participants sorted multiple images of own- and other-race persons according to identity in an implicit learning task and subsequently either matched novel images of learnt and previously unseen faces for identity (Experiment 1) or made old/new decisions for new images of learnt and unfamiliar identities (Experiment 2). Caucasian participants demonstrated own-race advantages during sorting, matching, and old/new recognition, while corresponding effects were absent in East Asian participants with substantial other-race expertise. Surprisingly, East Asian participants showed enhanced learning for other-race identities during matching in Experiment 1, which may reflect their increased motivation to individuate other-race faces. Thus, our results highlight the importance of perceptual expertise for own- and other-race processing, but may also lend support to recent suggestions on how expertise and socio-cognitive factors can interact.

Development of a facial-expression database of Chinese Han, Hui and Tibetan people

Recently, cross-cultural facial-expression recognition has become a research hotspot, and a standardised facial-expression material system can significantly help researchers compare and demonstrate the results of other studies. We developed a facial-expression database of Chinese Han, Hui and Tibetan ethnicities. In this study, six basic human facial expressions (and one neutral expression) were collected from 200 Han, 220 Hui and 210 Tibetan participants who lived in these regions. Four experts on each ethnicity evaluated the facial-expression images according to the expressions, and only those achieving inter-rater agreement were retained. Subsequently, 240 raters evaluated these images according to the seven emotions and rated the intensity of the expressions. Consequently, 2980 images were included in the database, including 930 images of Han individuals, 962 images of Hui individuals and 1088 images of Tibetan individuals. In conclusion, the facial-expression database of Chinese Han, Hui and Tibetan people was representative and reliable with a recognition rate of over 60%, making it well-suited for cross-cultural research on emotions.

Face perception: A brief journey through recent discoveries and current directions

Faces are a rich source of information about the people around us. Identity, state of mind, emotions, intentions, age, gender, ethnic background, attractiveness and a host of other attributes about an individual can be gleaned from a face. When face perception fails, dramatic psycho-social consequences can follow at the individual level, as in the case of prosopagnosic parents who are unable to recognize their children at school pick-up. At the species level, social interaction patterns are shaped by human face perception abilities. The computational feat of recognizing faces and facial attributes, and the challenges overcome by the human brain to achieve this feat, have fascinated generations of vision researchers. In this paper, we present a brief overview of some of the milestones of discovery as well as outline a selected set of current directions and open questions on this topic.

The Effects of Blur and Inversion on the Recognition of Ambient Face Images

When viewing unfamiliar faces that vary in expressions, angles, and image quality, observers make many recognition errors. Specifically, in unconstrained identity-sorting tasks, observers struggle to cope with variation across different images of the same person while succeeding at telling different people apart. The use of ambient face images in this simple card-sorting task reveals the magnitude of these face recognition errors and suggests a useful platform to reexamine the nature of face processing using naturalistic stimuli. In the present study, we chose to investigate the impact of two basic stimulus manipulations (image blur and face inversion) on identity sorting with ambient images. Although these manipulations are both known to affect face processing when well-controlled, frontally viewed face images are used, examining how they affect performance for ambient images is an important step toward linking the large body of research using controlled face images to more ecologically valid viewing conditions. Briefly, we observed a high cost of image blur regardless of blur magnitude, and a strong inversion effect that affected observers’ sensitivity to extrapersonal variability but did not affect the number of unique identities they estimated were present in the set of images presented to them.

Becoming Familiar With a Newly Encountered Face: Evidence of an Own-Race Advantage

Adults' ability to match identity in images of unfamiliar faces is impaired for other- compared with own-race faces; their ability to match identity in images of familiar faces is independent of face race. Exposure to within-person variability in appearance plays a key role in face learning. Past research suggests that children need exposure to higher levels of variability than adults to learn a new face-a difference that has been attributed to experience. We predicted that adults' limited experience with other-race faces would result in their needing exposure to higher levels of variability when learning other- compared with own-race faces. We introduced adults to four new identities (two own-race; two other-race) in one of the three conditions: a single image, a low-variability video (filmed on 1 day), or a high-variability video (filmed across 3 days). Adults' ability to recognize new instances of learned identities improved in the low-variability condition for own-race faces but only in the high-variability condition for other-race faces. We discuss learning mechanisms that might drive this difference-a difference we attribute to experience.

O Uso de Biomarcadores em Pesquisas de Marketing

Resumo A aproximação do marketing com a neurociência tem gerado expectativa tanto na academia quanto no mercado, em especial na última década. Apesar do interesse e das promessas de resultados, lacunas de conhecimento neurobiológico são percebidas acerca de formas de coleta e análise de dados. Este estudo apresenta e compara algumas ferramentas neurocientíficas que são fundamentadas em respostas não cognitivas do cérebro humano. A coleta e a análise de biomarcadores, como hormônios e níveis de atividade elétrica muscular, podem ser utilizadas em pesquisas de comportamento humano relacionadas ao consumo ou em outras interações com ações de marketing. A metodologia de aplicação dessas ferramentas, medidas resultantes e possíveis interpretações de comportamento também são discutidas, com ênfase em futura agenda de pesquisa.

An investigation of the effect of race-based social categorization on adults' recognition of emotion

Emotion recognition is important for social interaction and communication, yet previous research has identified a cross-cultural emotion recognition deficit: Recognition is less accurate for emotions expressed by individuals from a cultural group different than one’s own. The current study examined whether social categorization based on race, in the absence of cultural differences, influences emotion recognition in a diverse context. South Asian and White Canadians in the Greater Toronto Area completed an emotion recognition task that required them to identify the seven basic emotional expressions when posed by members of the same two groups, allowing us to tease apart the contributions of culture and social group membership. Contrary to our hypothesis, there was no mutual in-group advantage in emotion recognition: Participants were not more accurate at recognizing emotions posed by their respective racial in-groups. Both groups were more accurate at recognizing expressions when posed by South Asian faces, and White participants were more accurate overall compared to South Asian participants. These results suggest that in a diverse environment, categorization based on race alone does not lead to the creation of social out-groups in a way that negatively impacts emotion recognition.

Faces, people and the brain: The 45th Sir Frederic Bartlett Lecture

The fact that the face is a source of diverse social signals allows us to use face and person perception as a model system for asking important psychological questions about how our brains are organised. A key issue concerns whether we rely primarily on some form of generic representation of the common physical source of these social signals (the face) to interpret them, or instead create multiple representations by assigning different aspects of the task to different specialist components. Variants of the specialist components hypothesis have formed the dominant theoretical perspective on face perception for more than three decades, but despite this dominance of formally and informally expressed theories, the underlying principles and extent of any division of labour remain uncertain. Here, I discuss three important sources of constraint: first, the evolved structure of the brain; second, the need to optimise responses to different everyday tasks; and third, the statistical structure of faces in the perceiver’s environment. I show how these constraints interact to determine the underlying functional organisation of face and person perception.

KDEF-PT: Valence, Emotional Intensity, Familiarity and Attractiveness Ratings of Angry, Neutral, and Happy Faces

The Karolinska Directed Emotional Faces (KDEF) is one of the most widely used human facial expressions database. Almost a decade after the original validation study (Goeleven et al., 2008), we present subjective rating norms for a sub-set of 210 pictures which depict 70 models (half female) each displaying an angry, happy and neutral facial expressions. Our main goals were to provide an additional and updated validation to this database, using a sample from a different nationality (N = 155 Portuguese students, M = 23.73 years old, SD = 7.24) and to extend the number of subjective dimensions used to evaluate each image. Specifically, participants reported emotional labeling (forced-choice task) and evaluated the emotional intensity and valence of the expression, as well as the attractiveness and familiarity of the model (7-points rating scales). Overall, results show that happy faces obtained the highest ratings across evaluative dimensions and emotion labeling accuracy. Female (vs. male) models were perceived as more attractive, familiar and positive. The sex of the model also moderated the accuracy of emotional labeling and ratings of different facial expressions. Each picture of the set was categorized as low, moderate, or high for each dimension. Normative data for each stimulus (hits proportion, means, standard deviations, and confidence intervals per evaluative dimension) is available as supplementary material (available at https://osf.io/fvc4m/).

Differences in holistic processing do not explain cultural differences in the recognition of facial expression

The aim of this study was to investigate the causes of the own-race advantage in facial expression perception. In Experiment 1, we investigated Western Caucasian and Chinese participants’ perception and categorization of facial expressions of six basic emotions that included two pairs of confusable expressions (fear and surprise; anger and disgust). People were slightly better at identifying facial expressions posed by own-race members (mainly in anger and disgust). In Experiment 2, we asked whether the own-race advantage was due to differences in the holistic processing of facial expressions. Participants viewed composite faces in which the upper part of one expression was combined with the lower part of a different expression. The upper and lower parts of the composite faces were either aligned or misaligned. Both Chinese and Caucasian participants were better at identifying the facial expressions from the misaligned images, showing interference on recognizing the parts of the expressions created by holistic perception of the aligned composite images. However, this interference from holistic processing was equivalent across expressions of own-race and other-race faces in both groups of participants. Whilst the own-race advantage in recognizing facial expressions does seem to reflect the confusability of certain emotions, it cannot be explained by differences in holistic processing.

Experience-based human perception of facial expressions in Barbary macaques (Macaca sylvanus)

BACKGROUND

Facial expressions convey key cues of human emotions, and may also be important for interspecies interactions. The universality hypothesis suggests that six basic emotions (anger, disgust, fear, happiness, sadness, and surprise) should be expressed by similar facial expressions in close phylogenetic species such as humans and nonhuman primates. However, some facial expressions have been shown to differ in meaning between humans and nonhuman primates like macaques. This ambiguity in signalling emotion can lead to an increased risk of aggression and injuries for both humans and animals. This raises serious concerns for activities such as wildlife tourism where humans closely interact with wild animals. Understanding what factors (i.e., experience and type of emotion) affect ability to recognise emotional state of nonhuman primates, based on their facial expressions, can enable us to test the validity of the universality hypothesis, as well as reduce the risk of aggression and potential injuries in wildlife tourism.

METHODS

The present study investigated whether different levels of experience of Barbary macaques, Macaca sylvanus, affect the ability to correctly assess different facial expressions related to aggressive, distressed, friendly or neutral states, using an online questionnaire. Participants' level of experience was defined as either: (1) naïve: never worked with nonhuman primates and never or rarely encountered live Barbary macaques; (2) exposed: shown pictures of the different Barbary macaques' facial expressions along with the description and the corresponding emotion prior to undertaking the questionnaire; (3) expert: worked with Barbary macaques for at least two months.

RESULTS

Experience with Barbary macaques was associated with better performance in judging their emotional state. Simple exposure to pictures of macaques' facial expressions improved the ability of inexperienced participants to better discriminate neutral and distressed faces, and a trend was found for aggressive faces. However, these participants, even when previously exposed to pictures, had difficulties in recognising aggressive, distressed and friendly faces above chance level.

DISCUSSION

These results do not support the universality hypothesis as exposed and naïve participants had difficulties in correctly identifying aggressive, distressed and friendly faces. Exposure to facial expressions improved their correct recognition. In addition, the findings suggest that providing simple exposure to 2D pictures (for example, information signs explaining animals' facial signalling in zoos or animal parks) is not a sufficient educational tool to reduce tourists' misinterpretations of macaque emotion. Additional measures, such as keeping a safe distance between tourists and wild animals, as well as reinforcing learning via videos or supervised visits led by expert guides, could reduce such issues and improve both animal welfare and tourist experience.

Social Categories Alone Are Insufficient to Elicit an In-Group Advantage in Perceptions of Within-Person Variability

Within-person variability affects identity perception of other-race faces more than own-race faces; when participants sort images into piles representing different identities, they sort photographs of two other-race identities into more piles than two own-race identities. These results have been interpreted in terms of perceptual expertise, such that lack of experience with other-race faces leads to reduced ability to extract identity-relevant information across images. However, an alternative explanation is that sociocognitive factors (e.g., cognitive disregard for out-group faces) lead to differences in the number of perceived identities. Here, we examined whether social factors alone elicit an in-group advantage in perceptions of within-person variability. Caucasian participants sorted 40 photographs of two unfamiliar Caucasian identities (20 photographs/model) into piles based on the number of identities they believed were present. Half of the participants were told that the images were of students attending their university (in-group), whereas half were told that the images were of students attending a rival university (out-group). Participants sorted the photographs into a comparable number of identities for in- and out-group faces. This lack of an in-group advantage suggests that sociocognitive factors alone cannot account for differences in the number of perceived identities across faces from two categories.