Us versus them: Understanding the process of race perception with event-related brain potentials

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.

Neural timing of the other-race effect across the lifespan: A review

Face race influences the way we process faces, so that faces of a different ethnic group are processed for identity less efficiently than faces of one's ethnic group - a phenomenon known as the Other-Race Effect (ORE). Although widely replicated, the ORE is still poorly characterized in terms of its development and the underlying mechanisms. In the last two decades, the Event-Related Potential (ERP) technique has brought insight into the mechanisms underlying the ORE and has demonstrated potential to clarify its development. Here, we review the ERP evidence for a differential neural processing of own-race and other-race faces throughout the lifespan. In infants, race-related processing differences emerged at the N290 and P400 (structural encoding) stages. In children, race affected the P100 (early processing, attention) perceptual stage and was implicitly encoded at the N400 (semantic processing) stage. In adults, processing difficulties for other-race faces emerged at the N170 (structural encoding), P200 (configuration processing) and N250 (accessing individual representations) perceptual stages. Early in processing, race was implicitly encoded from other-race faces (N100, P200 attentional biases) and in-depth processing preferentially applied to own-race faces (N200 attentional bias). Encoding appeared less efficient (Dm effects) and retrieval less recollection-based (old/new effects) for other-race faces. Evidence admits the contribution of perceptual, attentional, and motivational processes to the development and functioning of the ORE, offering no conclusive support for perceptual or socio-cognitive accounts. Cross-racial and non-cross-racial studies provided convergent evidence. Future research would need to include less represented ethnic populations and the developmental population.

The role of task demands in racial face encoding

People more accurately remember faces of their own racial group compared to faces of other racial groups; this phenomenon is called the other-race effect. To date, numerous researchers have devoted themselves to exploring the reasons for this other-race effect, and they have posited several theoretical explanations. One integrated explanation is the categorization-individuation model, which addresses two primary ways (categorization and individuation) of racial face processing and emphasizes the emergence of these two ways during the encoding stage. Learning-recognition and racial categorization tasks are two classical tasks used to explore racial face processing. Event-related potentials can facilitate investigation of the encoding differences of own- and other-race faces under these two typical task demands. Unfortunately, to date, results have been mixed. In the current study, we investigated whether categorization and individuation differ for own- and other-race faces during the encoding stage by using racial categorization and learning-recognition tasks. We found that task demands not only influence the encoding of racial faces, but also have a more profound effect in the encoding stage of recognition tasks for other-race faces. More specifically, own-race faces demonstrate deeper structural encoding than other-race faces, with less attentional involvement. Moreover, recognitions tasks might ask for more individual-level encoding, requiring more attentional resources in the early stage that may be maintained until relatively late stages. Our results provide some evidence concerning task selection for future racial face studies and establish a groundwork for a unified interpretation of racial face encoding.

Societies and other kinds of social groups

People live in distinct groups, notably territory-holding societies, whose boundaries aren't neatly defined by the traits that Pietraszewski describes for his socially aligned groups (or SAGs), as I propose calling them, which occur both within and between our societies. Although studying SAGs could prove enlightening, societies are essential human groups that likely existed long before the complex SAGs of today.

Race and early face-sensitive event-related potentials in children and adults

Studies examining children's face perception have revealed developmental changes in early and face-sensitive event-related potential (ERP) components. Children also tend to show racial biases in their face perception and evaluation of others. The current study examined how early face-sensitive ERPs are influenced by face race in children and adults. A second objective examined face recognition proficiency and implicit racial bias in relation to ERP responses to own- and other-race faces. Electroencephalographic responses were recorded while Caucasian children and adults viewed Caucasian and East Asian faces. Participants also completed recognition tasks and an IAT with Caucasian and East Asian faces. Other-race faces elicited larger P100 amplitudes than own-race faces. Furthermore, adults with better other-race recognition proficiency showed larger P100 amplitude responses to other-race faces compared with adults with worse other-race recognition proficiency. In addition, larger implicit biases favoring own-race individuals were associated with larger P100 to N170 peak-to-peak amplitudes for other-race faces in adults. In contrast, larger implicit biases favoring own-race individuals were associated with smaller P100 to N170 peak-to-peak amplitudes for both own- and other-race faces in 8- to 10-year-olds. There was also an age-related decrease in P100 to N170 peak-to-peak amplitudes for own-race faces among 5- to 10-year-olds with better own-race recognition proficiency. The age-related decrease in N170 latency for other-race faces was also more pronounced in 5- to 10-year-olds with better other-race recognition proficiency. Thus, recognition proficiency and implicit racial bias are associated with early ERP responses in adults and children, but in different ways.

An evaluation of the reading the mind in the eyes test's psychometric properties and scores in South Africa-cultural implications

The 'Reading the Mind in the Eyes' test (RMET) has been translated and tested in many cultural settings. Results indicate that items show variability in meeting the original psychometric testing criteria. Individuals from non-Western cultures score differently on the RMET. As such, questions arise as to the cross-cultural validity of the RMET. This study tested the English version of the RMET, that consists almost exclusively of White faces, at a large South African university to determine its validity in a culturally diverse context. A total of 443 students from a range of different demographic backgrounds completed the instrument. Students were selected using simple random sampling. 30 out of the 36 items continued to show satisfactory psychometric properties. Further evidence shows significant differences based on race and home language in both overall scores and item level scores. Black race and African home language respondents show lower RMET scores and different item level perspectives on certain mental states. The current RMET is not inclusive. It requires stimuli reflecting more races and cultures. This lack of diversity is likely to be influencing and biasing results and psychometric properties. The continued exclusion of racial stimuli such as Black race is also promoting a systemic discriminatory instrument. These results have cultural implications for how we interpret and use the RMET.

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.

Explicit Categorization Goals Affect Attention-Related Processing of Race and Gender During Person Construal

Faces are categorized by gender and race very quickly, seemingly without regard to perceivers' goals or motivations, suggesting an automaticity to these judgments that has downstream consequences for evaluations, stereotypes, and social interactions. The current study investigated the extent to which early neurocognitive processes involved in the categorization of faces vary when participants' tasks goals were to categorize faces by race or by gender. In contrast to previous findings, task-related differences were found, such that differentiation in the P2 event-related potential (ERP) according to perceived gender was facilitated by having an explicit task goal of categorizing faces by gender; however, the P2 was sensitive to race regardless of task goals. Use of principal components analysis (PCA) revealed two underlying components that comprised the P2 and that were differentially sensitive to the gender and race of the faces, depending on participants' top-down task goals. Results suggest that top-down task demands facilitate discrimination of faces along the attended dimension within less than 200 ms, but that the effect of top-down task demands may not be evident when examining early ERP components that reflect more than one distinct underlying process.

Effects of Minimal Grouping On Implicit Prejudice, Infrahumanization, and Neural Processing Despite Orthogonal Social Categorizations

Racial prejudice is a pervasive and pernicious form of intergroup bias. However, a mounting number of studies show that re-categorization-even into minimal groups-can overcome the typical consequences of racial and other group classifications. We tested the effects of minimal grouping on implicit prejudice and infrahumanization using a paradigm in which race was orthogonal to group membership. This allowed us to examine whether knowledge of group membership overrides obvious category differences. We found that participants infrahumanized and showed implicit bias toward the minimal out-group, despite the crosscutting presence of race, and in fact did not show any of the usual implicit racial bias. In addition, Event-Related Potentials (ERPs) showed an early race effect followed by distinct reactions on the basis of group as processing continued. This is evidence that arbitrary social classifications can engender in-group preference even in the presence of orthogonal, visually salient categorizations.

Gender identity relevance predicts preferential neural processing of same-gendered faces

The very early perceptional processes that underlie social categorization can be detected with event-related brain potentials (ERPs). Using this methodology, the present work aims to detect differential attentional processing of ingroup and outgroup members based on gender categories. Specifically, three EEG studies tested how factors that enhance social identity relevance, namely gender identification and contextual salience of gender representation, moderate neural gender categorization effects. Study 1 showed that both women (Study 1a) and men (Study 1b) were more likely to show preferential attention to ingroup over outgroup members, but only when they identified strongly with their gender group. Study 2 showed that when gender categories in an intergroup leadership context were made salient (i.e., when women were numerically underrepresented versus equally represented compared to men), women, irrespective of their level of gender identification, showed preferential attention to ingroup over outgroup members. Together, this work provides empirical evidence for (1) the neural gender categorization effect among both men and women as soon as 100 ms after face perception and (2) the moderating role of factors that enhance social identity relevance in early gender categorization.

Grappling With Implicit Social Bias: A Perspective From Memory Research

There is now widespread consensus that social biases often influence actions independently of the actor's intention or awareness. The notion that we are sometimes blind to the origins of our thoughts, attitudes, and behaviors also features prominently in research into domain-general human memory systems, which has a long history of distinguishing between implicit and explicit repercussions of past experience. A shared challenge across these fields of study is thus to identify techniques for effectively managing the contents of our memory stores, particularly those aspects into which we have limited metacognitive insight. In the present review, we examine recent developments in the cognitive neuroscience of human memory that speak to this challenge as it applies to the social domain. One area of progress pertains to the role of individuation, the process of attending to and representing in memory unique characteristics of individuals, which can limit the influence of generalizations based on social categories. A second body of work concerns breakthroughs in understanding memory consolidation, which determines the fate of newly encoded memories. We discuss the promise of each of these developments for identifying ways to become better stewards of our social minds. More generally, we suggest that, as with other forms of learning and memory, intentional practice and rehearsal may be critical in learning to minimize unwanted biases.

Are Rich People Perceived as More Trustworthy? Perceived Socioeconomic Status Modulates Judgments of Trustworthiness and Trust Behavior Based on Facial Appearance

In the era of globalization, people meet strangers from different countries more often than ever. Previous research indicates that impressions of trustworthiness based on facial appearance play an important role in interpersonal cooperation behaviors. The current study examined whether additional information about socioeconomic status (SES), including national prosperity and individual monthly income, affects facial judgments and appearance-based trust decisions. Besides reproducing previous conclusions that trustworthy faces receive more money than untrustworthy faces, the present study showed that high-income individuals were judged as more trustworthy than low-income individuals, and also were given more money in a trust game. However, trust behaviors were not modulated by the nationality of the faces. The present research suggests that people are more likely to trust strangers with a high income, compared with individuals with a low income.

Using trial-level data and multilevel modeling to investigate within-task change in event-related potentials

EEG data, and specifically the ERP, provide psychologists with the power to examine quickly occurring cognitive processes at the native temporal resolution at which they occur. Despite the advantages conferred by ERPs to examine processes at different points in time, ERP researchers commonly ignore the trial-to-trial temporal dimension by collapsing across trials of similar types (i.e., the signal averaging approach) because of constraints imposed by repeated measures ANOVA. Here, we present the advantages of using multilevel modeling (MLM) to examine trial-level data to investigate change in neurocognitive processes across the course of an experiment. Two examples are presented to illustrate the usefulness of this technique. The first demonstrates decreasing differentiation in N170 amplitude to faces of different races across the course of a race categorization task. The second demonstrates attenuation of the ERN as participants commit more errors within a task designed to measure implicit racial bias. Although the examples presented here are within the realm of social psychology, the use of MLM to analyze trial-level EEG data has the potential to contribute to a number of different theoretical domains within psychology.

Race Guides Attention in Visual Search

It is known that faces are rapidly and even unconsciously categorized into social groups (black vs. white, male vs. female). Here, I test whether preferences for specific social groups guide attention, using a visual search paradigm. In Experiment 1 participants searched displays of neutral faces for an angry or frightened target face. Black target faces were detected more efficiently than white targets, indicating that black faces attracted more attention. Experiment 2 showed that attention differences between black and white faces were correlated with individual differences in automatic race preference. In Experiment 3, using happy target faces, the attentional preference for black over white faces was eliminated. Taken together, these results suggest that automatic preferences for social groups guide attention to individuals from negatively valenced groups, when people are searching for a negative emotion such as anger or fear.

Own-race faces capture attention faster than other-race faces: evidence from response time and the N2pc

Studies have shown that people are better at recognizing human faces from their own-race than from other-races, an effect often termed the Own-Race Advantage. The current study investigates whether there is an Own-Race Advantage in attention and its neural correlates. Participants were asked to search for a human face among animal faces. Experiment 1 showed a classic Own-Race Advantage in response time both for Chinese and Black South African participants. Using event-related potentials (ERPs), Experiment 2 showed a similar Own-Race Advantage in response time for both upright faces and inverted faces. Moreover, the latency of N2pc for own-race faces was earlier than that for other-race faces. These results suggested that own-race faces capture attention more efficiently than other-race faces.