Intergroup relationships do not reduce racial bias in empathic neural responses to pain

Empathic pain: Underlying neural mechanism

Empathy is usually regarded as the ability to perceive the emotional state of others, which is an altruistic motivation to promote prosocial behavior and thus plays a key role in human life and social development. Empathic pain-the capacity to feel and understand the pain of others-constitutes a significant aspect in the study of empathy behaviors. For an extended duration, investigations into empathic pain have predominantly centered on human neuroimaging studies. Fortunately, recent advancements have witnessed the utilization of animal models in the exploration of the fundamental neural underpinnings of empathic pain. There is substantial evidence implicating multiple brain regions and neural networks in the generation and maintenance of empathic pain. Nevertheless, further elucidation of the neural mechanisms underlying empathic pain is warranted. This review provides a concise overview of prior studies on the neural mechanisms of empathic pain, outlining the pertinent brain regions, neural pathways, synaptic mechanisms, and associated molecules while also delving into future prospects.

Group membership modulates empathic neural responses to pain in deaf individuals

Empathy deficiencies are prevalent among deaf individuals. It has yet to be determined whether they exhibit an ingroup bias in empathic responses. This study employed explicit and implicit empathy tasks (i.e. attention-to-pain-cue [A-P] task and attention-to-nonpain-cue [A-N] task) to explore the temporal dynamics of neural activities when deaf individuals were processing painful/nonpainful stimuli from both ingroup models (deaf people) and outgroup models (hearing people), which aims to not only assist deaf individuals in gaining a deeper understanding of their intergroup empathy traits but also to aid in the advancement of inclusive education. In the A-P task, we found that (i) ingroup priming accelerated the response speed to painful/nonpainful pictures; (ii) the N2 amplitude of painful pictures was significantly more negative than that of nonpainful pictures in outgroup priming trials, whereas the N2 amplitude difference between painful and nonpainful pictures was not significant in ingroup priming trials. For N1 amplitude of the A-N task, we have similar findings. However, this pattern was reversed for P3/late positive component amplitude of the A-P task. These results suggest that the deaf individuals had difficulty in judging whether hearing individuals were in pain. However, their group identification and affective responses could shape the relatively early stage of pain empathy.

The role of external factors in affect-sharing and their neural bases

Affect-sharing, the ability to vicariously feel another person's emotions, is the primary component of empathy that is typically thought to rely on the observer's capacity to feel the emotions of others. However, external signals, such as the target's physical characteristics, have been demonstrated to influence affect-sharing in the neuroscientific literature that speaks to the underappreciated role of external factors in eliciting affect-sharing. We consider factors that influence affect-sharing, including physical cues, emotional cues, situational factors, and observer-target relationships, as well as the neural circuits involved in these processes. Our review reveals that, while neural network activation is primarily responsible for processing affect-sharing, external factors also co-activate a top-down cognitive processing network to modulate the conscious process of affect-sharing. From this knowledge, an integrative framework of external factor interactions with affect-sharing are explained in detail. Finally, we identify critical areas for future research in social and affective neuroscience, including research gaps and incorporation of ecologically valid paradigms.

EEG evidence for racial ingroup bias in collective empathy for pain

Previous research on racial ingroup bias in empathy for pain focused on neural responses to a single person's suffering. It is unclear whether empathy for simultaneously perceived multiple individuals' pain (denoted as collective empathy in this study) is also sensitive to perceived racial identities of empathy targets. We addressed this issue by recording electroencephalography from Chinese adults who responded to racial identities of 2 × 2 arrays of Asian or White faces in which 4 faces, 1 face, or no face showed painful expressions. Participants reported greater feelings of others' pain and their own unpleasantness when viewing 4 compared to 1 (or no) painful faces. Behavioral responses to racial identities of faces revealed decreased speeds of information acquisition when responding to the face arrays with 4 (vs. 1 or no) painful expressions of Asian (but not White) faces. Moreover, Asian compared to White face arrays with 4 (vs. 1 or no) painful expressions elicited a larger positive neural response at 160-190 ms (P2) at the frontal/central electrodes and enhanced alpha synchronizations at 288-1,000 ms at the central electrodes. Our findings provide evidence for racial ingroup biases in collective empathy for pain and unravel its relevant neural underpinnings.

The vocal side of empathy: neural correlates of pain perception in spoken complaints

In the extensive neuroimaging literature on empathy for pain, few studies have investigated how this phenomenon may relate to everyday social situations such as spoken interactions. The present study used functional Magnetic Resonance Imaging (fMRI) to assess how complaints, as vocal expressions of pain, are empathically processed by listeners and how these empathic responses may vary based on speakers' vocal expression and cultural identity. Twenty-four French participants listened to short utterances describing a painful event, which were either produced in a neutral-sounding or complaining voice by both in-group (French) and out-group (French Canadian) speakers. Results suggest that the perception of suffering from a complaining voice increased activity in the emotional voice areas, composed of voice-sensitive temporal regions interacting with prefrontal cortices and the amygdala. The Salience and Theory of Mind networks, associated with affective and cognitive aspects of empathy, also showed prosody-related activity and specifically correlated with behavioral evaluations of suffering by listeners. Complaints produced by in- vs out-group speakers elicited sensorimotor and default mode activity, respectively, suggesting accent-based changes in empathic perspective. These results, while reaffirming the role of key networks in tasks involving empathy, highlight the importance of vocal expression information and social categorization processes when perceiving another's suffering during social interactions.

Neural dynamics of vicarious physical pain processing reflect impaired empathy toward sexually objectified versus non-sexually objectified women

Sexually objectified women are perceived as dehumanized. This may affect the behavioral and neural responses underlying the observer's empathic reactions for their physical pain, although this hypothesis still lacks empirical support. In the present study, we measured the electrophysiological activity of 30 participants (14 females and 16 males), in an empathy for physical pain paradigm in which pictures of sexualized and non-sexualized women were presented in painful and non-painful situations. The behavioral results revealed that sexualized women were evaluated as experiencing less pain than non-sexualized women. Neural evidence corroborated this finding showing that the perception of vicarious physical pain is lacking for sexualized women in both event-related potentials (ERPs) and brain oscillation domains. Specifically, the P2 component and the event-related synchronization/desynchronization (ERS/ERD) on the mu frequency band differed between painful and non-painful stimulation exclusively when women were not sexualized. Our results provide the first evidence that the neurophysiological responses to the vicarious experience of physical pain are dampened or even absent for sexualized women. These findings expand our understanding of the neurophysiological signatures of empathic processes and highlight the detrimental effect of a sexual-objectification bias in everyday contexts.

(Not) part of the team: Racial empathy bias in a South African minimal group study

Minimal Group Paradigm (MGP) research suggests that recategorization with an arbitrarily defined group may be sufficient to override empathy biases among salient social categories like race. However, most studies utilizing MGPs do not consider sufficiently the socio-historical contexts of social groups. Here we investigated whether the recategorization of White participants into arbitrarily defined mixed-race teams using a non-competitive MGP would ameliorate racial empathy biases towards ingroup team members in the South African context. Sixty participants rated their empathic and counter-empathic (Schadenfreude, Glückschmerz) responses to ingroup and outgroup team members in physically painful, emotionally distressing, and positive situations. As anticipated, results indicated significant ingroup team biases in empathic and counter-empathic responses. However, mixed-race minimal teams were unable to override ingroup racial empathy biases, which persisted across events. Interestingly, a manipulation highlighting purported political ideological differences between White and Black African team members did not exacerbate racial empathy bias, suggesting that such perceptions were already salient. Across conditions, an internal motivation to respond without prejudice was most strongly associated with empathy for Black African target individuals, regardless of their team status. Together, these results suggest that racial identity continues to provide a salient motivational guide in addition to more arbitrary group memberships, even at an explicit level, for empathic responding in contexts characterized by historical power asymmetry. These data further problematize the continued official use of race-based categories in such contexts.

Understanding racial bias through electroencephalography

Research on racial bias in social and cognitive psychology has focused on automatic cognitive processes such as categorisation or stereotyping. Neuroimaging has revealed differences in the neural circuit when processing social information about one's own or another's ethnicity. This review investigates the influence of racial bias on human behaviour by reviewing studies that examined changes in neural circuitry (i.e. ERP responses) during automatic and controlled processes elicited by specific tasks. This systematic analysis of specific ERP components across different studies provides a greater understanding of how social contexts are perceived and become associated with specific stereotypes and behavioural predictions. Therefore, investigating these related cognitive and neurobiological functions can further our understanding of how racial bias affects our cognition more generally and guide more effective programs and policies aimed at its mitigation.

Neural empathic response to disability: An ERP study of prejudice

While social neuroscience has already provided evidence for a deficit of affective empathy in racial prejudice, little is known about other less visible social categories when considered as an outgroup. We studied the process of empathy through event-related brain potentials (ERPs). We focused on the group "people with disabilities" as they are the target of a large amount of prejudice. Twenty-six participants performed a pain decision task. The mean amplitudes of N1, P2, N2-N3 and P3 components were recorded. Our results are consistent with previous work on prejudice, showing that the pain detection is modulated by group membership (with disabilities vs. without disabilities) on N2-N3, suggesting a better neural decoding of pain vs. non-pain in the without-disability condition. Critically, no effect of early sensory components (N1, P2) was found, and P3 was not moderated by disability. These findings indicate a different time course of empathic responses depending on the condition, suggesting that people with disabilities trigger specific empathic responses. Our results contribute to disentangling perceptual processes from affective empathy reactions.

The Effect of Cognitive Strategies and Facial Attractiveness on Empathic Neural Responses

Empathy is a phenomenon that brings together both emotions and an understanding of another person. Recent studies have disentangled the mechanisms of empathy into emotional and cognitive aspects. Event-related potential (ERP) studies suggest that emotional empathy is related to the modulation of the amplitude of early ERPs, and cognitive empathy is linked to later ERPs. In the current study, we examined the influences of facial attractiveness on empathic response and the effect of cognitive strategies with setting the participants' attention to attractiveness or pain. Participants (N= 19) viewed photos of physically attractive and unattractive men and women receiving painful stimulation. The amplitude of the N2 component measured at the frontal regions was more negative in painful stimulation compared to the non-painful, but only for attractive faces. There were no differences between painful and non-painful stimulation for unattractive faces. The amplitude of the P3 measured at the central-parietal region component was more positive in the painful condition compared to the non-painful one, but only when participants performed a pain judgment task. There were no differences in the attractiveness judgment task. This study showed that the attractiveness of a model and drawing the participants' attention to pain constitute an essential modulator of pain empathy.

Listen to my feelings! How prosody and accent drive the empathic relevance of complaining speech

Interpersonal communication often involves sharing our feelings with others; complaining, for example, aims to elicit empathy in listeners by vocally expressing a speaker's suffering. Despite the growing neuroscientific interest in the phenomenon of empathy, few have investigated how it is elicited in real time by vocal signals (prosody), and how this might be affected by interpersonal factors, such as a speaker's cultural background (based on their accent). To investigate the neural processes at play when hearing spoken complaints, twenty-six French participants listened to complaining and neutral utterances produced by in-group French and out-group Québécois (i.e., French-Canadian) speakers. Participants rated how hurt the speaker felt while their cerebral activity was monitored with electroencephalography (EEG). Principal Component Analysis of Event-Related Potentials (ERPs) taken at utterance onset showed culture-dependent time courses of emotive prosody processing. The high motivational relevance of ingroup complaints increased the P200 response compared to all other utterance types; in contrast, outgroup complaints selectively elicited an early posterior negativity in the same time window, followed by an increased N400 (due to ongoing effort to derive affective meaning from outgroup voices). Ingroup neutral utterances evoked a late negativity which may reflect re-analysis of emotively less salient, but culturally relevant ingroup speech. Results highlight the time-course of neurocognitive responses that contribute to emotive speech processing for complaints, establishing the critical role of prosody as well as social-relational factors (i.e., cultural identity) on how listeners are likely to "empathize" with a speaker.

Neuroscience and climate change: How brain recordings can help us understand human responses to climate change

There is little published neuroscience research on the psychology of climate change. This review outlines how carefully designed experiments that measure key neural processes, linked to specific cognitive processes, can provide powerful tools to answer research questions in climate change psychology. We review relevant literature from social neuroscience that can be applicable to environmental research-the neural correlates of fairness and cooperation, altruistic behaviour and personal values-and discuss important factors when translating environmental psychology constructs to neuroscientific measurement. We provide a practical overview of how to implement environmental neuroscience using electroencephalography, summarising important event-related potential components and how they can be used to answer questions in climate change psychology. Challenges for the field include accurate attribution of findings, both within and between studies, the need for interdisciplinary collaboration, peer review and reporting processes.

Emotivity in the Voice: Prosodic, Lexical, and Cultural Appraisal of Complaining Speech

Emotive speech is a social act in which a speaker displays emotional signals with a specific intention; in the case of third-party complaints, this intention is to elicit empathy in the listener. The present study assessed how the emotivity of complaints was perceived in various conditions. Participants listened to short statements describing painful or neutral situations, spoken with a complaining or neutral prosody, and evaluated how complaining the speaker sounded. In addition to manipulating features of the message, social-affiliative factors which could influence complaint perception were varied by adopting a cross-cultural design: participants were either Québécois (French Canadian) or French and listened to utterances expressed by both cultural groups. The presence of a complaining tone of voice had the largest effect on participant evaluations, while the nature of statements had a significant, but smaller influence. Marginal effects of culture on explicit evaluation of complaints were found. A multiple mediation analysis suggested that mean fundamental frequency was the main prosodic signal that participants relied on to detect complaints, though most of the prosody effect could not be linearly explained by acoustic parameters. These results highlight a tacit agreement between speaker and listener: what characterizes a complaint is how it is said (i.e., the tone of voice), more than what it is about or who produces it. More generally, the study emphasizes the central importance of prosody in expressive speech acts such as complaints, which are designed to strengthen social bonds and supportive responses in interactive behavior. This intentional and interpersonal aspect in the communication of emotions needs to be further considered in research on affect and communication.

Visual similarity and psychological closeness are neurally dissociable in the brain response to vicarious pain

Personal and vicarious experience of pain activate partially overlapping brain networks. This brain activity is further modulated by low- and high-order factors, e.g., the perceived intensity of the model's pain and the model's similarity with the onlooker, respectively. We investigated which specific aspect of similarity modulates such empathic reactivity, focusing on the potential differentiation between visual similarity and psychological closeness between the onlooker and different types of models. To this aim, we recorded fMRI data in neurotypical participants who observed painful and tactile stimuli delivered to an adult human hand, a baby human hand, a puppy dog paw, and an anthropomorphic robotic hand. The interaction between type of vicarious experience (pain, touch) and nature of model (adult, baby, dog, robot) showed that the right supramarginal gyrus (rSMG) was selectively active for visual similarity (more active during vicarious pain for the adult and baby models), while the anterior cingulate cortex (ACC) was more sensitive to psychological closeness (specifically linked to vicarious pain for the baby model). These findings indicate that visual similarity and psychological closeness between onlooker and model differentially affect the activity of brain regions specifically implied in encoding interindividual sharing of sensorimotor and affective aspects of vicarious pain, respectively.

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

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

Feeling Other People's Pain: An Event-Related Potential Study on Facial Attractiveness and Emotional Empathy

Empathy is the ability to understand and react to other people's inner states. Neuroimaging evidence suggests that there are two aspects of empathy which are subserved by distinct brain networks. The emotional aspect of empathy is reflected by bottom-up processes and the cognitive aspect of empathy is influenced by top-down processes. Both aspects can be studied by measuring the reaction of participants exposed to the pictures of models who feel physical pain, for example, having a needle stuck in their cheek. The early event-related potential (ERP) N2 has been reported in observing other’s physical pain and has been suggested as a biomarker of the emotional aspect of empathy. The present study investigated the time course of processing other’s pain and the influence of face attractiveness on the early ERP component. Participants (N = 24) viewed photos of physically attractive and unattractive men and women during painful (a needle in the check) and nonpainful stimulation (Q-tip touching the skin). N1 and P2 components were sensitive to face attractiveness. The amplitude of the N2 component was more positive for the stimuli associated with pain than for neutral stimuli, but only for unattractive faces. Therefore, we suggest that a difference in the N2 amplitude to pain in unattractive faces most likely reflects a difference in emphatic response depending on facial attractiveness.

Interactions between oxytocin receptor gene and intergroup relationship on empathic neural responses to others' pain

Empathic neural responses to others' suffering are subject to both social and biological influences. The present study tested the hypothesis that empathic neural responses to others' pain are more flexible in an intergroup context in G/G than A/A carriers of the oxytocin receptor gene (OXTR) (rs53576). We recorded event-related brain potentials to painful vs neutral expressions of Asian and Caucasian faces that were assigned to a fellow team or an opponent team in Chinese carriers of G/G or A/A allele of OXTR. We found that G/G carriers showed greater neural responses at 136-176 ms (P2) over the frontal/central region to painful vs neutral expressions of faces with shared either racial or mini group identity. In contrast, A/A carriers showed significant empathic neural responses in the P2 time window only to the faces with both shared racial and mini group identity. Moreover, the racial in-group bias in empathic neural responses varied across individuals' empathy traits and ethnic identity for G/G but not A/A carriers. Our findings provide electrophysiological evidence for greater flexibility of empathic neural responses in intergroup contexts in G/G (vs A/A) carriers of OXTR and suggest interactions between OXTR and intergroup relationships on empathy for others' suffering.

Meta-analysis of ERP investigations of pain empathy underlines methodological issues in ERP research

Empathy has received considerable attention from the field of cognitive and social neuroscience. A significant portion of these studies used the event-related potential (ERP) technique to study the mechanisms of empathy for pain in others in different conditions and clinical populations. These show that specific ERP components measured during the observation of pain in others are modulated by several factors and altered in clinical populations. However, issues present in this literature such as analytical flexibility and lack of type 1 error control raise doubts regarding the validity and reliability of these conclusions. The current study compiled the results and methodological characteristics of 40 studies using ERP to study empathy of pain in others. The results of the meta-analysis suggest that the centro-parietal P3 and late positive potential component are sensitive to the observation of pain in others, while the early N1 and N2 components are not reliably associated with vicarious pain observation. The review of the methodological characteristics shows that the presence of selective reporting, analytical flexibility and lack of type 1 error control compromise the interpretation of these results. The implication of these results for the study of empathy and potential solutions to improve future investigations are discussed.

Out of Sight Out of Mind: Perceived Physical Distance Between the Observer and Someone in Pain Shapes Observer's Neural Empathic Reactions

Social and affective relations may shape empathy to others' affective states. Previous studies also revealed that people tend to form very different mental representations of stimuli on the basis of their physical distance. In this regard, embodied cognition and embodied simulation propose that different physical distances between individuals activate different interpersonal processing modes, such that close physical distance tends to activate the interpersonal processing mode typical of socially and affectively close relationships. In Experiment 1, two groups of participants were administered a pain decision task involving upright and inverted face stimuli painfully or neutrally stimulated, and we monitored their neural empathic reactions by means of event-related potentials (ERPs) technique. Crucially, participants were presented with face stimuli of one of two possible sizes in order to manipulate retinal size and perceived physical distance, roughly corresponding to the close and far portions of social distance. ERPs modulations compatible with an empathic reaction were observed only for the group exposed to face stimuli appearing to be at a close social distance from the participants. This reaction was absent in the group exposed to smaller stimuli corresponding to face stimuli observed from a far social distance. In Experiment 2, one different group of participants was engaged in a match-to-sample task involving the two-size upright face stimuli of Experiment 1 to test whether the modulation of neural empathic reaction observed in Experiment 1 could be ascribable to differences in the ability to identify faces of the two different sizes. Results suggested that face stimuli of the two sizes could be equally identifiable. In line with the Construal Level and Embodied Simulation theoretical frameworks, we conclude that perceived physical distance may shape empathy as well as social and affective distance.

Empathy in female submissive BDSM practitioners

The practice of bondage/discipline, dominance/submission, sadism/masochism (BDSM) sometimes is associated with giving and receiving pain. It remains unresolved how BDSM practitioners perceive the pain of other people. This study investigated whether and how the BDSM experience affects human empathy. Experiment 1 measured trait empathy and subjective empathic responses in BDSM practitioners and control respondents. The results revealed lower trait empathy scores and subjective pain intensity ratings in the female submissive group (Subs) compared to controls. Experiment 2 measured participants' neural responses to others' suffering by recording event-related potentials (ERPs) from female Subs and controls while viewing painful and neutral expressions. We found that the differential amplitudes between painful and neutral expressions in the frontal N1 (92-112ms), frontal P2 (132-172ms) and central late LPP (700-1000ms) were reduced in the submissive group versus the control group. These findings suggest that being in the submissive role during BDSM practice weakens female individuals' empathic responses to others' suffering at both the behavioral and neural levels.

Racial Bias in Neural Response for Pain Is Modulated by Minimal Group

Whether empathic racial bias could be modulated is a subject of intense interest. The present study was carried out to explore whether empathic racial bias for pain is modulated by minimal group. Chinese/Western faces with neutral expressions receiving painful (needle penetration) or non-painful (Q-tip touch) stimulation were presented. Participants were asked to rate the pain intensity felt by Chinese/Western models of ingroup/outgroup members. Their implicit racial bias were also measured. Two lines of evidence indicated that the anterior cingulate cortex (ACC) was modulated by racial bias: (1) Chinese models elicited stronger activity than Western did in the ACC, and (2) activity in the ACC was modulated by implicit racial bias. Whereas the right anterior insula (rAI) were modulated by ingroup bias, in which ingroup member elicited stronger activity than outgroup member did. Furthermore, activity in the ACC was modulated by activity of rAI (i.e., ingroup bias) in the pain condition, while activity in the rAI was modulated by activity of ACC (i.e., racial bias) in the nopain condition. Our results provide evidence that there are different neural correlates for racial bias and ingroup bias, and neural racial bias for pain can be modulated by minimal group.

A Screening Mechanism Differentiating True from False Pain during Empathy

Empathizing with another's suffering is important in social interactions. Empathic behavior is selectively elicited from genuine, meaningful pain but not from fake, meaningless scenarios. However, the brain's screening mechanism of false information from meaningful events and the time course for the screening process remains unclear. Using EEG combined with principle components analysis (PCA) techniques, here we compared temporal neurodynamics between the observation of pain and no-pain pictures as well as between true (painful expressions and needle-penetrated arms) and false (needle-penetrated faces with neutral expressions) pain pictures. The results revealed that pain vs. no-pain information is differentiated in the very early ERP components, i.e., the N1/P1 for the face and arm pictures categories and the VPP/N170 for the facial expression category while the mid-latency ERP components, N2 and P3, played key roles in differentiating true from false situations. The complex of N2 and P3 components may serve as a screening mechanism through which observers allocate their attentions to more important or relevant events and screen out false environmental information. This is the first study to describe and provide a time course of the screening process during pain empathy. These findings shed new light on the understanding of empathic processing.

From the Brain to the Field: The Applications of Social Neuroscience to Economics, Health and Law

Social neuroscience aims to understand the biological systems that underlie people’s thoughts, feelings and actions in light of the social context in which they operate. Over the past few decades, social neuroscience has captured the interest of scholars, practitioners, and experts in other disciplines, as well as the general public who more and more draw upon the insights and methods of social neuroscience to explain, predict and change behavior. With the popularity of the field growing, it has become increasingly important to consider the validity of social neuroscience findings as well as what questions it can and cannot address. In the present review article, we examine the contribution of social neuroscience to economics, health, and law, three domains with clear societal relevance. We address the concerns that the extrapolation of neuroscientific results to applied social issues raises within each of these domains, and we suggest guidelines and good practices to circumvent these concerns.

Physical coldness enhances racial in-group bias in empathy: Electrophysiological evidence

Empathy for others' pain plays a key role in prosocial behavior and is influenced by intergroup relationships. Increasing evidence suggests greater empathy for racial in-group than out-group individuals' pain and the racial in-group bias undergoes sociocultural and biological influences. The present study further investigated whether and how physical environments influence racial in-group bias in empathy by testing the hypothesis that sensory experiences of physical coldness versus warmth enhance differential empathic neural responses to racial in-group vs. out-group individuals' suffering. We recorded event-related brain potentials to painful versus neutral expressions of same-race and other-race faces when participants held a cold or warm pack. We found that brain activity in the N2 (200-340ms) and P3 (400-600ms) time windows over the frontal/central region was positively shifted by painful (vs. neutral) expressions. Moreover, the N2/P3 empathic neural responses were significantly larger for same-race than other-race faces in the cold but not in the warm condition. Moreover, subjective ratings of different temperatures in the cold vs. warm conditions predicted larger changes of racial in-group bias in empathic neural responses in the N2 time window. Our findings suggest that sensory experiences of physical coldness can strengthen emotional resonance with same-race individuals.

Empathy as a driver of prosocial behaviour: highly conserved neurobehavioural mechanisms across species

Empathy reflects the natural ability to perceive and be sensitive to the emotional states of others, coupled with a motivation to care for their well-being. It has evolved in the context of parental care for offspring, as well as within kinship bonds, to help facilitate group living. In this paper, we integrate the perspectives of evolution, animal behaviour, developmental psychology, and social and clinical neuroscience to elucidate our understanding of the proximate mechanisms underlying empathy. We focus, in particular, on processing of signals of distress and need, and their relation to prosocial behaviour. The ability to empathize, both in animals and humans, mediates prosocial behaviour when sensitivity to others' distress is paired with a drive towards their welfare. Disruption or atypical development of the neural circuits that process distress cues and integrate them with decision value leads to callous disregard for others, as is the case in psychopathy. The realization that basic forms of empathy exist in non-human animals is crucial for gaining new insights into the underlying neurobiological and genetic mechanisms of empathy, enabling translation towards therapeutic and pharmacological interventions.

Embodied neural responses to others' suffering

To investigate whether and how facial mimicry in observers affects their empathic neural responses to others' pain expressions, we recorded event-related potentials (ERPs) from Chinese adults while viewing pain and neutral expressions of Asian and Caucasian faces. Facial mimicry was manipulated by allowing participants to freely move their facial muscles (the relaxed condition) or asking them to hold a pen horizontally using both teeth and lips to prevent facial muscle movement and facial mimicry (the blocked condition). We found that the frontal N1 at 100-120 ms was enlarged by pain vs. neutral expressions. The N1 modulation by facial expressions was significantly reduced in the blocked compared to relaxed conditions and this effect was observed for Asian but not Caucasian faces. The findings suggest that facial mimicry plays a causal role in the early empathic neural response and the embodied empathic neural responses are constrained by the racial intergroup relationship.

Mortality salience enhances racial in-group bias in empathic neural responses to others' suffering

Behavioral research suggests that mortality salience (MS) leads to increased in-group identification and in-group favoritism in prosocial behavior. What remains unknown is whether and how MS influences brain activity that mediates emotional resonance with in-group and out-group members and is associated with in-group favoritism in helping behavior. The current work investigated MS effects on empathic neural responses to racial in-group and out-group members' suffering. Experiments 1 and 2 respectively recorded event related potentials (ERPs) and blood oxygen level dependent signals to pain/neutral expressions of Asian and Caucasian faces from Chinese adults who had been primed with MS or negative affect (NA). Experiment 1 found that an early frontal/central activity (P2) was more strongly modulated by pain vs. neutral expressions of Asian than Caucasian faces, but this effect was not affected by MS vs. NA priming. However, MS relative to NA priming enhanced racial in-group bias in long-latency neural response to pain expressions over the central/parietal regions (P3). Experiment 2 found that MS vs. NA priming increased racial in-group bias in empathic neural responses to pain expression in the anterior and mid-cingulate cortex. Our findings indicate that reminding mortality enhances brain activity that differentiates between racial in-group and out-group members' emotional states and suggest a neural basis of in-group favoritism under mortality threat.

Racial bias in neural response to others' pain is reduced with other-race contact

Observing the pain of others has been shown to elicit greater activation in sensory and emotional areas of the brain suggested to represent a neural marker of empathy. This modulation of brain responses to others' pain is dependent on the race of the observed person, such that observing own-race people in pain is associated with greater activity in the anterior cingulate and bilateral insula cortices compared to other-race people. Importantly, it is not known how this racial bias to pain in other-race individuals might change over time in new immigrants or might depend on the level and quality of contact with people of the other-race. We investigated these issues by recruiting Chinese students who had first arrived in Australia within the past 6 months to 5 years and assessing their level of contact with other races across different social contexts using comprehensive rating scales. During fMRI, participants observed videos of own-race/other-race individuals, as well as own-group/other-group individuals, receiving painful or non-painful touch. The typical racial bias in neural responses to observed pain was evident, whereby activation in the anterior cingulate cortex (ACC) was greater for pain in own-race compared to other-race people. Crucially, activation in the anterior cingulate to pain in other races increased significantly with the level of contact participants reported with people of the other race. Importantly, this correlation did not depend on the closeness of contact or personal relationships, but simply on the overall level of experience with people of the other race in their every-day environment. Racial bias in neural responses to others' pain, as a neural marker of empathy, therefore changes with experience in new immigrants at least within 5 years of arrival in the new society and, crucially, depends on the level of contact with people of the other race in every-day life contexts.