Neural signals in amygdala predict implicit prejudice toward an ethnic outgroup

On the neural networks of self and other bias and their role in emergent social interactions

Extensive research has documented the brain networks that play an integral role in bias, or the alteration and filtration of information processing in a manner that fundamentally favors an individual. The roots of bias, whether self- or other-oriented, are a complex constellation of neural and psychological processes that start at the most fundamental levels of sensory processing. From the millisecond information is received in the brain it is filtered at various levels and through various brain networks in relation to extant intrinsic activity to provide individuals with a perception of reality that complements and satisfies the conscious perceptions they have for themselves and the cultures in which they were reared. The products of these interactions, in turn, are dynamically altered by the introduction of others, be they friends or strangers who are similar or different in socially meaningful ways. While much is known about the various ways that basic biases alter specific aspects of neural function to support various forms of bias, the breadth and scope of the phenomenon remains entirely unclear. The purpose of this review is to examine the brain networks that shape (i.e., bias) the self-concept and how interactions with similar (ingroup) compared to dissimilar (outgroup) others alter these network (and subsequent interpersonal) interactions in fundamental ways. Throughout, focus is placed on an emerging understanding of the brain as a complex system, which suggests that many of these network interactions likely occur on a non-linear scale that blurs the lines between network hierarchies.

Right amygdala and caudate activation patterns predict implicit attitudes toward people with autism spectrum disorders and physical disabilities, respectively

Attitudes toward people with disabilities tend to be negative, regardless of the visibility of the disorder traits. Individuals with autism spectrum disorder (ASD) experience stigmatization that is rooted in negative attitudes or prejudice toward them because of their social awkwardness. The neural underpinnings of attitudes toward people with disabilities remain unclear. In this study, we focused on implicit attitudes toward people with ASD and physical disabilities, which are more visible than ASD, and investigated whether implicit attitudes were predicted by using neural activity with multivoxel pattern analysis (MVPA) in the prejudice network. Thirty-six, right-handed, Japanese, university students without disabilities participated. Two implicit association tests (IAT) toward people with ASD and physical disabilities revealed negative implicit attitudes. In the MRI scanner, participants performed a one-back task by using the same picture sets of IATs to examine their neural responses toward people with ASD and physical disabilities. According to the MVPA results, activation patterns of the right amygdala and right caudate significantly predicted implicit attitudes toward people with ASD and physical disabilities, respectively. These results suggest that implicit attitudes toward ASD and physical disabilities can be predicted by using neural signals from different regions within the prejudice network.

Representation of intergroup conflict in the human brain

This NeuroView explores intergroup conflict by synthesizing intergroup differences with three group-related neurocognitive processes. We suggest that intergroup differences at the aggregated-group level and interpersonal level are neurally dissociated and independently influence group dynamics as well as ingroup-outgroup conflicts.

Neural mechanisms of brand love relationship dynamics: Is the development of brand love relationships the same as that of interpersonal romantic love relationships?

Brand love is a relationship between brands and consumers. Managing the relationship is an important issue for marketing strategy since it changes according to temporal flow. Brand love theories, including their dynamics, have been developed based on interpersonal romantic love theories. Although many brand love studies have provided useful findings, the neural mechanism of brand love remains unclear. Especially, its dynamics have not been considered from a neuroscience perspective. The present study addressed the commonalities and differentiations of activated brain regions between brand love and interpersonal romantic love relationships using a quantitative neuroimaging meta-analytic approach, from the view of brain connectivity. Regarding the mental processes of each love relationship related to these activated brain regions, decoding analysis was conducted using the NeuroQuery platform to prevent reverse inference. The results revealed that different neural mechanisms and mental processes were distinctively involved in the dynamics of each love relationship, although the anterior insula overlapped across all stages and the reinforcement learning system was driven between both love relationships in the early stage. Remarkably, regarding the distinctive mental processes, although prosocial aspects were involved in the mental processes of interpersonal romantic love relationships across all stages, they were not involved in the mental processes of brand love relationships. Conclusively, although common brain regions and mental processes between both love relationships were observed, neural mechanisms and mental processes in brand love relationship dynamics might be innately different from those in the interpersonal romantic love relationship dynamics. As this finding indicates essential distinctiveness between both these relationships, theories concerning interpersonal romantic love should be applied cautiously when investigating brand love relationship dynamics.

Explicit and implicit attitudes toward smoking: Dissociation of attitudes and different characteristics for an implicit attitude in smokers and nonsmokers

Smoking is a global health risk for premature death and disease. Recently, addictive behaviors, like smoking, were considered to be guided by explicit and implicit processes. The existence of a dissociation between the two attitudes in nonsmokers and the causes of the differences in implicit attitudes toward smoking have not been fully investigated. We investigated the explicit and implicit attitudes toward smoking via a self-reported scale and the single category implicit association test (SC-IAT), respectively, among undergraduate and graduate health sciences students. In addition, we applied the drift-diffusion model (DDM) on the SC-IAT and examined the behavioral characteristics that caused differences in implicit attitude toward smoking between smokers and nonsmokers. The results showed the existence of a dissociation between explicit and implicit attitudes toward smoking among nonsmokers. In addition, nonsmokers had a higher decision threshold than smokers and a higher drift rate in the condition where negative words were associated with smoking. Nonsmokers engaged in SC-IAT with more cautious attitudes and responded more easily in a negative condition since it was consistent with their true attitudes. Conversely, smokers did not show a significant difference in the drift rate between the conditions. These results suggested that the differences in an implicit attitude between smokers and nonsmokers were caused by differences in evidence accumulation speed between the positive and negative conditions. The existence of dissociation between implicit and explicit attitudes toward smoking may indicate the difficulty of measuring true attitude in nonsmokers in a questionnaire survey. Additionally, the DDM results explained the difference of implicit attitude between smokers and nonsmokers; it may provide information on the mechanisms of addictive behaviors and a basis for therapy. However, whether these results are affected by cultural differences requires further investigation.

Measuring implicit mental representations related to ethnic stereotypes with ERPs: An exploratory study

The present investigation used ERPs to detect the activation of implicit stereotypical representations associated to different ethnic groups, by means of an implicit paradigm. 285 sentences were presented to 20 Italian Caucasian participants while EEG signals were recorded from 128 scalp sites. Sentences could either violate (Incongruent condition), non-violate (Congruent condition) or be neutral (Neutral condition) with regard to stereotypical concepts concerning non-Caucasian ethnic groups (e.g. Asians, Africans, Arabs). No awareness or judgment about stereotypes was required. Participants were engaged in a fictitious task, ignoring the overall study's purpose. The results showed that Incongruent terminal words elicited a greater anterior N400 response (300-500 ms) compared to Congruent and Neutral words, reflecting a difficulty in integrating the information incongruent with pre-existing stereotypical knowledge. The participant's individual amplitude values of the N400-Difference Wave (Incongruent - Congruent), showed a direct correlation with the individual racism scores obtained at the Subtle and Blatant Prejudice Scale, administered at the end of the experimental session. Intra-cortical sources explaining the N400 involved areas of the social cognition network such as the medial frontal cortex (BA10) and the inferior temporal gyrus (BA20) which are known to support processing of information about other people and impression formation. Moreover, Congruent terminal words evoked a greater P300 response (500-600 ms) compared to the other conditions, possibly reflecting the merging of incoming inputs with anticipated semantic information. A late post-N400 frontal positivity (650-800 ms) was found to be larger to sentences concerning other-race characters (ether congruent or incongruent) compared to sentences involving own-race characters (neutral). The study corroborated the effectiveness of neurophysiological measures to assess implicit complex semantic representations and circumventing social desirability-related problems.

Socioeconomic Status Inequalities Partially Mediate Racial and Ethnic Differences in Children's Amygdala Volume

BACKGROUND

While race/ethnicity and socioeconomic status (SES) impact brain structures such as the amygdala, less is known on whether or not family SES partially explains why amygdala volume is smaller for racial and ethnic minority groups.

PURPOSE

This study tested the mediating effects of family SES on racial and ethnic differences in right and left amygdala volume.

METHODS

We borrowed the structural Magnetic Resonance Imaging (sMRI) data of the Children Brain Cognitive Development (ABCD) study, a brain imaging investigation of childhood brain development in the US. The total sample was 8977, 9-10-year-old children. The independent variables were race and ethnicity. The primary outcomes were right and left amygdala volume. Age, sex, household size, and marital status were the covariates. Multiple SES indicators such as family income, subjective family SES, parental employment, parental education, and neighborhood income were the mediators. To analyze the data, we used regression models without and with our mediators. Sobel test was used to test if these mediational paths are statistically significant.

RESULTS

Black and Latino children had smaller amygdala sizes than non-Latino White children. The effects of race and ethnicity on amygdala volume were partially mediated by SES indicators, suggesting that one of the many reasons Black and Latino children have smaller volumes of right and left amygdala is their lower SES.

CONCLUSIONS

For American children, lower family and neighborhood SES indicators partially, but not fully, explain smaller amygdala sizes of Black and Latino children compared to non- Latino White children.

The neural mechanisms of threat and reconciliation efforts between Muslims and non-Muslims

To reduce the escalation of intergroup conflict, it is important that we understand the processes related to the detection of group-based threat and reconciliation. In the present study, we investigated the neural mechanisms of such processes using functional Magnetic Resonance Imaging (fMRI). Functional neuroimaging techniques may shed light on quick, automatic responses to stimuli that happen outside of conscious awareness and are thus increasingly difficult to quantify relying only on participants' self-reported experiences. They may further provide invaluable insight into physiological processes occurring in situations of sensitive nature, whereby participants-deliberately or not-may withhold their honest responses due to social desirability. Non-Muslim Western Caucasian participants watched short video clips of stereotypical Middle-Eastern Muslim males threatening their ingroup, offering reconciliation to the ingroup, or making a neutral statement. Threatening statements led to increased activation in the amygdala, insula, supramarginal gyrus, and temporal lobe. Reconciliation efforts led to increased activation in the prefrontal cortex, anterior cingulate gyrus, and caudate. The results suggest that threat detection is a relatively automatic process while evaluating and responding to reconciliation offers requires more cognitive efforts. The implications of these findings and future research directions are discussed.

Prefrontal Cortex Response to Threat: Race by Age Variation in 9-10 Year Old Children

BACKGROUND

Considerable research has suggested that race and age are two major determinants of brain development, including but not limited to development of the prefrontal cortex (PFC). Minorities' Diminished Returns (MDRs), however, suggests that race (as a proxy of racism) may interact with various determinants of human and brain development. Minimal knowledge, however, exists on whether age and race also interact on shaping PFC response to threat among American children.

PURPOSE

Using data from a task-based functional brain imaging study and considering race as a sociological rather than a biological construct, we investigated combined effects of race and age on prefrontal cortical (PFC) response to threat. We explored racial heterogeneities in the association between age and PFC response to threat by comparing Black and White children.

METHODS

This study used the task-based functional Magnetic Resonance Imaging (fMRI) data from the Adolescents Brain Cognitive Development (ABCD) study, a national, landmark, multi-center brain imaging investigation of 9-10 years old children in the US. The primary outcomes were mean beta weights of n-back runs measuring PFC response to threating versus neutral face contrast in the following regions of interest (ROIs): left hemisphere-lateral orbito-frontal, left hemisphere -superior-frontal, right hemisphere -caudal middle frontal, and right hemisphere -superior frontal cortex. The independent variable was age. Covariates were sex, ethnicity, family socioeconomic status, and neighborhood socioeconomic status. Race was the focal moderator. To analyze the data, we used linear regression models without and with interactions and SES as covariates.

RESULTS

We included 5,066 9-10 years old children. Age and race did not show direct effects on PFC response to threatening relative to neutral faces. While ethnicity, sex, and socioeconomic status were controlled, age and race showed a systematic interaction on PFC response to threatening relative to neutral faces.

CONCLUSIONS

For American children, race and age do not have direct effects but multiplicative effects on PFC response to threat. The results may be reflective of social inequalities in how Black and White children are socialized and developed. The results are important given the role of the PFC in regulating the limbic system response to threat. Coordinated work of the limbic system and PFC is a core element of children's behavioral and emotional development. Future research is needed on how social stratification and racism shape emotion processing and regulation of American children in response to threat.

Elucidating the role of the posterior medial frontal cortex in social conflict processing

A fundamental function of the brain is learning via new information. Studies investigating the neural basis of information-based learning processes indicate an important role played by the posterior medial frontal cortex (pMFC) in representing conflict between an individual's expectation and new information. However, specific function of the pMFC in this process remains relatively indistinct. Particularly, it's unclear whether the pMFC plays a role in the detection of conflict of incoming information, or the update of their belief after new information is provided. In an fMRI scanner, twenty-eight Japanese students viewed scenarios depicting various pro-social/anti-social behaviors. Participants rated how likely Japanese and South Korean students would perform each behavior, followed by feedback of the actual likelihood. They were then asked to rerate the scenarios after the fMRI session. Participants updated their second estimates based on feedback, with estimate changes more pronounced for favorable feedback (e.g., higher likelihood of pro-social behavior than expected) despite nationality, indicating participants were willing to view other people favorably. The fMRI results demonstrated activity in a part of the pMFC, the dorsomedial prefrontal cortex (dmPFC), was correlated with social conflict (difference between participant's estimate and actual likelihood), but not the corresponding belief update. Importantly, activity in a different part within the dmPFC was more sensitive to unfavorable trials compared to favorable trials. These results indicate sensitivity in the pMFC (at least within the dmPFC) relates to conflict between desirable outcomes versus reality, as opposed to the associated update of belief.