Processing Of Other-race Faces Research Articles

Event-related potential correlates of implicit processing of own- and other-race faces in children

Human adults typically experience difficulties in recognizing and discriminating individual faces belonging to racial groups other than their own. The origin of this “other-race” effect is set in infancy, but the understanding of its developmental course is fragmented. We aimed to access the mechanisms of the other-race effect in childhood by unraveling the neural time course of own- and other-race face processing during a masked priming paradigm. White 6- and 7-year-old children (N = 19) categorized fully visible Asian (other-race) or White (own-race) target faces according to gender. Target faces were preceded by masked same-identity or different-identity prime faces, matching the target for race and gender. We showed an early priming effect on the N100 component, with larger amplitude to different-face pairs than to same-face pairs, and a later race effect on the N200 component, with larger amplitude to own-race face pairs than to other-race face pairs. Critically, race did not interact with priming at any processing stage (P100, N100, P200, N200, or P300). Our results suggest that race could have a temporally limited impact on face processing and that the implicit and unconscious identity processing of own- and other-race faces could be similar in 6- and 7-year-olds, depicting an immature other-race effect during childhood.

Default categorization of outgroup faces and the other race effect: Commentary on the special issue.

This commentary addresses how studies examining the neurophysiological correlates of racial categorization can provide insight into the neurocognitive mechanisms of the other-race effect in recognition memory. Several articles in the special issue describe how event-related potentials (ERPs) have been used to examine processing of faces that vary according to race, some of which have concluded that larger ERP amplitudes elicited by other-race (relative to own-race) faces indicates less efficient visual processing of other-race faces. I describe findings from ERP studies of race categorization that suggest an alternative interpretation-that other-race faces elicit stronger categorization, which impedes individuation of other-race faces. Suggestions for future research are offered.

Visual attention to own- versus other-race faces: Perspectives from learning mechanisms and task demands.

Multiple factors have been proposed to contribute to the other-race effect in face recognition, including perceptual expertise and social-cognitive accounts. Here, we propose to understand the effect and its contributing factors from the perspectives of learning mechanisms that involve joint learning of visual attention strategies and internal representations for faces, which can be modulated by quality of contact with other-race individuals including emotional and motivational factors. Computational simulations of this process will enhance our understanding of interactions among factors and help resolve inconsistent results in the literature. In particular, since learning is driven by task demands, visual attention effects observed in different face-processing tasks, such as passive viewing or recognition, are likely to be task specific (although may be associated) and should be examined and compared separately. When examining visual attention strategies, the use of more data-driven and comprehensive eye movement measures, taking both spatial-temporal pattern and consistency of eye movements into account, can lead to novel discoveries in other-race face processing. The proposed framework and analysis methods may be applied to other tasks of real-life significance such as face emotion recognition, further enhancing our understanding of the relationship between learning and visual cognition.

Neural correlates of subordinate-level categorization of own- and other-race faces in infancy

Perceptual narrowing is a domain-general process in which infants move from a broad sensitivity to a wide range of stimuli to developing expertise within often experienced native stimuli (Maurer & Werker, 2014). One outcome of this is the own-race bias, characterized by an increasing difficulty in discriminating other-race faces with age and experience for those raised in a racially homogenous environment (Anzures, Quinn, Pascalis, Slater, Tanaka, & Lee, 2013). Theorists have proposed that this is due to a categorization-individuation process, wherein infants begin to categorize non-native stimuli but continue to individuate native stimuli (Hugenberg, Young, Bernstein, & Sacco, 2010; Nelson, 2001). Exposure to multiple exemplars during initial learning has been found to facilitate infant categorization of other-species faces while exposure to a single exemplar does not (Dixon, Reynolds, Romano, Roth, Stumpe, Guy, & Mosteller, 2019). The goal of this study was to investigate the effects of initial learning conditions on infants' ability to individuate and categorize own- and other-race faces. Ten-month-old infants were familiarized with a single exemplar or multiple exemplars of own- or other-race faces. Event-related potentials (ERPs) were recorded while infants were presented with the familiar face(s) they were exposed to during familiarization, novel faces from the same race used during familiarization, and novel faces from a race other than the one used in familiarization. Infants familiarized with a single exemplar, regardless of race, showed significant differences in both the Nc component (Negative central, associated with visual attention) and the LSW (late slow wave, associated with recognition memory) between familiar and novel faces at the subordinate-level category of race. No differences were found across familiarization conditions for the P400 component associated with face processing. Infants familiarized with multiple exemplars showed no evidence of discriminating faces at the categorical or individual level. Results suggest that, in contrast to other-species faces, infants at this age may process human faces more efficiently when familiarized with a single exemplar. The implications of the current findings are discussed in relation to the impact of initial learning conditions on infants' ability to individuate and categorize own- and other-species faces and social implications of infants' processing of other-race faces.

More elaborate processing of own-race faces and less elaborate processing of other-race faces contribute to the other-race effect in face memory.

Research suggests that own-race faces are naturally memorized in a more elaborate (e.g., many features of a face or the whole face) way, whereas other-race faces are memorized in a less elaborate (e.g., only selected features of the face) manner. Here, we tested if instructions for judgements about the whole face and a single facial feature modulated the other-race effect in face memory. White participants performed whole-face and single-feature tasks while memorizing White and Black faces for later recognition. Encoding instructions had a stronger impact on own-race than other-race faces. Whole-face instructions increased the other-race effect, whereas single-feature instructions decreased it. Own-race faces in the whole-face task demonstrated event-related potential (ERP) patterns of memory encoding comparable to previously observed natural memory encoding, suggesting naturally more elaborate encoding of own-race faces. ERPs of memory encoding for other-race faces were similar between task conditions and comparable to previously observed natural encoding patterns, suggesting naturally less elaborate encoding. No impact of the encoding tasks was found on ERPs related to memory retrieval, which may be an artefact of a perceptual task that does not enhance semantic details in memory. The current results indicate that some contributions to the other-race effect are more elaborate (more detailed) memory encoding for own-race faces and less elaborate (less detailed) memory encoding for other-race faces. This study also provides evidence for more malleability of own-race than other-race faces through task instructions, consistent with assumptions of perceptual learning theories of the other-race effect.

Change detection vs. change localization for own-race and other-race faces.

The other-race effect (ORE) is a well-known phenomenon in which people discriminate and recognize faces from their ethnic group more accurately than faces from other ethnic groups. Holistic processing, or the mandatory tendency to process all parts of an object together, has been proposed as an explanation for the ORE. According to the holistic perspective of the ORE, other-race faces might be subject to weaker holistic processing than own-race faces. However, evidence for this hypothesis is inconsistent. Although it is generally assumed that holistic processing helps the individuation of objects, holistic processing may also come at a cost. Specifically, holistic processing may reduce the capacity to localize changes in the constituent parts of an object, but not in detecting changes to an object as a whole. In the present study, we examined change detection and change localization accuracy for Caucasian and African faces, and houses. Performance was better for change detection than change localization for Caucasian faces. While clear costs of holistic processing for Caucasian faces were thus found, the difference between change localization and change detection was not obvious for African faces. However, childhood exposure to other-race people correlated with change detection for African faces, but not with change localization for African faces. Our results thus show that holistic processing of other-race faces may depend on early contact with other-race people.

The effect of implicit racial bias on recognition of other-race faces

Previous research has established a possible link between recognition performance, individuation experience, and implicit racial bias of other-race faces. However, it remains unclear how implicit racial bias might influence other-race face processing in observers with relatively extensive experience with the other race. Here we examined how recognition of other-race faces might be modulated by observers’ implicit racial bias, in addition to the effects of experience and face recognition ability. Caucasian participants in a culturally diverse city completed a memory task for Asian and Caucasian faces, an implicit association test, a questionnaire assessing experience with Asians and Caucasians, and a face recognition ability test. As expected, recognition performance for Asian faces was positively predicted by increased face recognition ability, and experience with Asians. More importantly, it was also negatively predicted by increased positive bias towards Asians, which was modulated by an interaction between face recognition ability and implicit bias, with the effect of implicit bias observed predominantly in observers with high face recognition ability. Moreover, the positions of the first two fixations when participants learned the other-race faces were affected by different factors, with the first fixation modulated by the effect of experience and the second fixation modulated by the interaction between implicit bias and face recognition ability. Taken together, these findings suggest the complexity in understanding the perceptual and socio-cognitive influences on the other-race effect, and that observers with high face recognition ability may more likely evaluate racial features involuntarily when recognizing other-race faces.

Electrophysiological correlates of unconscious processes of race

The study aimed to examine the neural mechanisms underlying implicit other-race face processing by the use of the masked and unmasked priming manipulation. Two types of prime-target pairs were presented while recording Event-related potentials (ERPs): Same face pairs (prime-target were identical faces), and Different face pairs (prime-target were different faces). Prime-target pairs were half Asian (other-race) and half Caucasian (own-race) faces. The face stimuli on each pair were of the same gender and race. Participants (all Caucasians) had to decide whether the target was a male or a female face (gender task). The prime face could be unmasked or masked. On the behavioral side, our findings showed a race effect, that is slower reaction times (RTs) for other-race than own-race face stimuli, regardless of masking. On the ERPs side, our data showed a race effect across all components analyzed (P100, N100, N200, P300), under both the unmasked and masked manipulations. Besides, we found, in the unmasked condition, a priming effect as a function of race on the N100, N200, and P300 components; but, interestingly, in the masked condition, only on the P300. Overall, our findings provide evidence that race information is available very early in the brain and can strongly activate and influence people’s behaviors even without conscious awareness.

The other-race effect and holistic processing across racial groups

It is widely accepted that holistic processing is important for face perception. However, it remains unclear whether the other-race effect (ORE) (i.e. superior recognition for own-race faces) arises from reduced holistic processing of other-race faces. To address this issue, we adopted a cross-cultural design where Malaysian Chinese, African, European Caucasian and Australian Caucasian participants performed four different tasks: (1) yes–no face recognition, (2) composite, (3) whole-part and (4) global–local tasks. Each face task was completed with unfamiliar own- and other-race faces. Results showed a pronounced ORE in the face recognition task. Both composite-face and whole-part effects were found; however, these holistic effects did not appear to be stronger for other-race faces than for own-race faces. In the global–local task, Malaysian Chinese and African participants demonstrated a stronger global processing bias compared to both European- and Australian-Caucasian participants. Importantly, we found little or no cross-task correlation between any of the holistic processing measures and face recognition ability. Overall, our findings cast doubt on the prevailing account that the ORE in face recognition is due to reduced holistic processing in other-race faces. Further studies should adopt an interactionist approach taking into account cultural, motivational, and socio-cognitive factors.

Do perceptual expertise and implicit racial bias predict early face-sensitive ERP responses?

Studies examining the visual perception of face race have revealed mixed findings regarding the presence or direction of effects on early face-sensitive event-related potential (ERP) components. Few studies have examined how early ERP components are influenced by individual differences in bottom-up and top-down processes involved in face perception, and how such factors might interact to influence early face-sensitive ERP components has yet to be investigated. Thus, the current study examined whether P100, N170, and P200 responses can be predicted by individual differences in own- and other-race face recognition, implicit racial bias, and their interaction. Race effects were observed in the P100, N170, and P200 responses. Other-race face recognition, implicit racial biases, and their interaction explained a significant amount of unique variability in N170 responses when viewing other-race faces. Responses to own-race faces were minimally influenced with only implicit racial bias predicting a significant amount of unique variability in N170 latency when viewing own-race faces. Face recognition, implicit racial bias, or their interaction did not predict P100 responses. The current findings suggest that face recognition abilities and its interaction with implicit racial bias modulate the early stages of other-race face processing.

Recognising other-race faces is more effortful: The effect of individuation instructions on encoding-related ERP Dm effects

Humans are better at recognising faces from their own vs. another ethnic background. Socio-cognitive theories of this own-race bias (ORB) propose that reduced recognition of other-race faces results from less motivation to attend to individuating information during encoding. Accordingly, individuation instructions that explain the phenomenon and instruct participants to attend to other-race faces during learning attenuate or eliminate the ORB. However, it is still unclear how exactly such instructions affect other-race face processing. We addressed this question by investigating encoding-related event-related brain potentials, contrasting neural activity of subsequently remembered and forgotten items (Dm effects). In line with socio-cognitive accounts, individuation instructions reduced the ORB. Critically, instructions increased Dm effects for other-race faces, suggesting that more processing resources were allocated to these faces during encoding. Thus, compensating for reduced experience with other-race faces is possible to some extent, but additional resources are needed to decrease difficulties resulting from a lack of perceptual expertise.

Development of Effective Connectivity during Own- and Other-Race Face Processing: A Granger Causality Analysis.

Numerous developmental studies have suggested that other-race effect (ORE) in face recognition emerges as early as in infancy and develops steadily throughout childhood. However, there is very limited research on the neural mechanisms underlying this developmental ORE. The present study used Granger causality analysis (GCA) to examine the development of children's cortical networks in processing own- and other-race faces. Children were between 3 and 13 years. An old-new paradigm was used to assess their own- and other-race face recognition with ETG-4000 (Hitachi Medical Co., Japan) acquiring functional near infrared spectroscopy (fNIRS) data. After preprocessing, for each participant and under each face condition, we obtained the causal map by calculating the weights of causal relations between the time courses of [oxy-Hb] of each pair of channels using GCA. To investigate further the differential causal connectivity for own-race faces and other-race faces at the group level, a repeated measure analysis of variance (ANOVA) was performed on the GCA weights for each pair of channels with the face race task (own-race face vs. other-race face) as the within-subject variable and the age as a between-subject factor (continuous variable). We found an age-related increase in functional connectivity, paralleling a similar age-related improvement in behavioral face processing ability. More importantly, we found that the significant differences in neural functional connectivity between the recognition of own-race faces and that of other-race faces were modulated by age. Thus, like the behavioral ORE, the neural ORE emerges early and undergoes a protracted developmental course.

Increased N250 amplitudes for other-race faces reflect more effortful processing at the individual level

The N250 and N250r (r for repetition, signaling a difference measure of priming) has been proposed to reflect the activation of perceptual memory representations for individual faces. Increased N250r and N250 amplitudes have been associated with higher levels of familiarity and expertise, respectively. In contrast to these observations, the N250 amplitude has been found to be larger for other-race than own-race faces in recognition memory tasks. This study investigated if these findings were due to increased identity-specific processing demands for other-race relative to own-race faces and whether or not similar results would be obtained for the N250 in a repetition priming paradigm. Only Caucasian participants were available for testing and completed two tasks with Caucasian, African-American, and Chinese faces. In a repetition priming task, participants decided whether or not sequentially presented faces were of the same identity (individuation task) or same race (categorization task). Increased N250 amplitudes were found for African-American and Chinese faces relative to Caucasian faces, replicating previous results in recognition memory tasks. Contrary to the expectation that increased N250 amplitudes for other-race face would be confined to the individuation task, both tasks showed similar results. This could be due to the fact that face identity information needed to be maintained across the sequential presentation of prime and target in both tasks. Increased N250 amplitudes for other-race faces are taken to represent increased neural demands on the identity-specific processing of other-race faces, which are typically processed less holistically and less on the level of the individual.

Neural correlates of own- and other-race face processing in infants: A near-infrared spectroscopic study

Neural correlates of own- and other-race face processing in infants: A near-infrared spectroscopic study

The effects of prediction on the perception for own-race and other-race faces.

Human beings do not passively perceive important social features about others such as race and age in social interactions. Instead, it is proposed that humans might continuously generate predictions about these social features based on prior similar experiences. Pre-awareness of racial information conveyed by others' faces enables individuals to act in “culturally appropriate” ways, which is useful for interpersonal relations in different ethnicity groups. However, little is known about the effects of prediction on the perception for own-race and other-race faces. Here, we addressed this issue using high temporal resolution event-related potential techniques. In total, data from 24 participants (13 women and 11 men) were analyzed. It was found that the N170 amplitudes elicited by other-race faces, but not own-race faces, were significantly smaller in the predictable condition compared to the unpredictable condition, reflecting a switch to holistic processing of other-race faces when those faces were predictable. In this respect, top-down prediction about face race might contribute to the elimination of the other-race effect (one face recognition impairment). Furthermore, smaller P300 amplitudes were observed for the predictable than for unpredictable conditions, which suggested that the prediction of race reduced the neural responses of human brains.

On the other side of the fence: effects of social categorization and spatial grouping on memory and attention for own-race and other-race faces.

The term “own-race bias” refers to the phenomenon that humans are typically better at recognizing faces from their own than a different race. The perceptual expertise account assumes that our face perception system has adapted to the faces we are typically exposed to, equipping it poorly for the processing of other-race faces. Sociocognitive theories assume that other-race faces are initially categorized as out-group, decreasing motivation to individuate them. Supporting sociocognitive accounts, a recent study has reported improved recognition for other-race faces when these were categorized as belonging to the participants' in-group on a second social dimension, i.e., their university affiliation. Faces were studied in groups, containing both own-race and other-race faces, half of each labeled as in-group and out-group, respectively. When study faces were spatially grouped by race, participants showed a clear own-race bias. When faces were grouped by university affiliation, recognition of other-race faces from the social in-group was indistinguishable from own-race face recognition. The present study aimed at extending this singular finding to other races of faces and participants. Forty Asian and 40 European Australian participants studied Asian and European faces for a recognition test. Faces were presented in groups, containing an equal number of own-university and other-university Asian and European faces. Between participants, faces were grouped either according to race or university affiliation. Eye tracking was used to study the distribution of spatial attention to individual faces in the display. The race of the study faces significantly affected participants' memory, with better recognition of own-race than other-race faces. However, memory was unaffected by the university affiliation of the faces and by the criterion for their spatial grouping on the display. Eye tracking revealed strong looking biases towards both own-race and own-university faces. Results are discussed in light of the theoretical accounts of the own-race bias.

Neural perspectives on the other-race effect

Psychological studies have long shown that human memory is superior for faces of our own-race than for faces of other-races. In this paper, we review neural studies of own- versus other-race face processing. These studies divide naturally into those focused on socioaffective aspects of the other-race effect and those directed at high-level visual processing differences. The socioaffective studies consider how subconscious bias and emotional responses affect brain areas such as the amygdala, anterior cingulate cortex, and parahippocampal gyrus. The visual studies focus on face-selective areas in the ventral stream, such as the fusiform face area (FFA). In both cases, factors such as experience, familiarity, social/emotional responses, cultural learning, and bias modulate the patterns of neural activity elicited in response to own- and other-race faces.

Computational perspectives on the other-race effect

Psychological studies have long shown that human memory is superior for faces of our own-race than for faces of other-races. In this paper, we review computational studies of own- versus other-race face processing. Computational models examine the visual challenges of representing the uniqueness of individual faces that vary both within and across demographic categories. These models isolate the visual components of the other-race effect and provide an objective control for socioaffective responses to other-race faces. This control allows researchers to compare and test the role of experience/contact in the other-race effect, using various operational definitions of this theoretical construct. The models show that to produce an other-race effect computationally, biased experience or learning must intervene during the process of feature selection. This implicates the critical importance of “developmental” learning in the other-race effect.

Neural correlates of own- and other-race face recognition in children: A functional near-infrared spectroscopy study

The present study used the functional Near-infrared Spectroscopy (fNIRS) methodology to investigate the neural correlates of elementary school children's own- and other-race face processing. An old-new paradigm was used to assess children's recognition ability of own- and other-race faces. FNIRS data revealed that other-race faces elicited significantly greater [oxy-Hb] changes than own-race faces in the right middle frontal gyrus and inferior frontal gyrus regions (BA9) and the left cuneus (BA18). With increased age, the [oxy-Hb] activity differences between own- and other-race faces, or the neural other-race effect (NORE), underwent significant changes in these two cortical areas: at younger ages, the neural response to the other-race faces was modestly greater than that to the own-race faces, but with increased age, the neural response to the own-race faces became increasingly greater than that to the other-race faces. Moreover, these areas had strong regional functional connectivity with a swath of the cortical regions in terms of the neural other-race effect that also changed with increased age. We also found significant and positive correlations between the behavioral other-race effect (reaction time) and the neural other-race effect in the right middle frontal gyrus and inferior frontal gyrus regions (BA9). These results taken together suggest that children, like adults, devote different amounts of neural resources to processing own- and other-race faces, but the size and direction of the neural other-race effect and associated functional regional connectivity change with increased age.

Holistic Processing for Other-Race Faces in Chinese Participants Occurs for Upright but Not Inverted Faces

Recent evidence suggests stronger holistic processing for own-race faces may underlie the own-race advantage in face memory. In previous studies Caucasian participants have demonstrated larger holistic processing effects for Caucasian over Asian faces. However, Asian participants have consistently shown similar sized effects for both Asian and Caucasian faces. We investigated two proposed explanations for the holistic processing of other-race faces by Asian participants: (1) greater other-race exposure, (2) a general global processing bias. Holistic processing was tested using the part-whole task. Participants were living in predominantly own-race environments and other-race contact was evaluated. Despite reporting significantly greater contact with own-race than other-race people, Chinese participants displayed strong holistic processing for both Asian and Caucasian upright faces. In addition, Chinese participants showed no evidence of holistic processing for inverted faces arguing against a general global processing bias explanation. Caucasian participants, in line with previous studies, displayed stronger holistic processing for Caucasian than Asian upright faces. For inverted faces there were no race-of-face differences. These results are used to suggest that Asians may make more general use of face-specific mechanisms than Caucasians.