Oxytocin modulates the racial bias in neural responses to others’ suffering

Neuronal and therapeutic perspectives on empathic pain: A rational insight

Empathy is the capacity to experience and understand the feelings of others, thereby playing a key role in a person's mental well-being essentially by promoting kindness and a sense of belongingness to the group. However, too much empathy may result in psychological problems such as empathic distress, compassion fatigue, and burnout, collectively termed empathic pain. Several brain regions are implicated in processing empathic pain perception. Neuroimaging investigations bring in the context of brain structures involved in this emotional exchange, pointing toward the anterior insula (AI) and anterior cingulate cortex (ACC), indicating an overlap between the neural representation of direct and simulative pain. To discern such overlaps, therapeutic techniques for managing empathic pain require understanding different brain regions and their respective neural networks. At the moment, empathic pain is being treated using various methods, including pharmacological treatments such as antidepressants and psychological treatments such as mindfulness or meditation. For instance, researchers have been exploring the modulatory effects of neurotransmitters like serotonin, norepinephrine, and oxytocin on individuals' responses to empathic pain experience. Importantly, this review focuses on the specific brain parts and their unique roles in neurobiological pathways associated with emphatic pain and how shared neural networks play into available treatment options, suggesting possible future health benefits. Such an understanding of empathy can lead to more efficient management of types of care, focusing on enhancing social connections and mental well-being.

The oxytocinergic system and racial ingroup bias in empathic neural activity

Studies have indicated that the human brain exhibits a more robust neural empathic response towards individuals of the same racial ingroup than those of the outgroup. However, the impact of the oxytocinergic system on the dynamic connectivity between brain regions involved in racial ingroup bias in empathy (RIBE) and its implications for real-life social interaction intention remains unclear. To address this gap, we employed functional magnetic resonance imaging (fMRI) to investigate RIBE-modulated neural activities and the influence of the oxytocinergic system at both neural and behavioral levels. Participants homozygous for the A/A and G/G genotypes of the oxytocin receptor gene (OXTR) rs53576 polymorphism underwent scanning while making judgments about painful versus non-painful stimuli in same-race versus other-race scenarios following either oxytocin (OT) or placebo treatment. The results revealed greater activity in the anterior cingulate cortex (ACC) and anterior insula (AI) in response to same-race compared to other-race models in the G/G group but not in the A/A group. RIBE also modulated the connections between bilateral AI and the ACC, and the effect of OT on this modulatory effect was moderated by genotype rs53576 and interpersonal trust. Moreover, more extensive changes in AI-ACC connections were associated with higher levels of revenge intention in the low interpersonal trust group. Overall, our findings suggest a pivotal role of the oxytocinergic system in the RIBE-modulated neural activities and revenge intention in human interactions with the modulatory effect of interpersonal trust. This article is part of the Special Issue on "Empathic Pain".

Why Moral Bioenhancement Cannot Reliably Produce Virtue

Moral bioenhancement presents the possibility of enhancing morally desirable emotions and dispositions. While some scholars have proposed that moral bioenhancement can produce virtue, we argue that within a virtue ethics framework moral bioenhancement cannot reliably produce virtue. Moreover, on a virtue ethics framework, the pursuit of moral bioenhancement carries moral risks. To make this argument, we consider three aspects of virtue-its motivational, rational, and behavioral components. In order to be virtuous, we argue, a person must (i) take pleasure in doing the right thing and have the correct motivational attitudes; (ii) reason correctly about what is called for in a particular ethical dilemma; and (iii) intentionally and continuously practice and cultivate virtues. These dimensions of morality-in short: precisely those emphasized in a virtue ethics framework-cannot be consistently or reliably met using existing moral bioenhancement technology.

Do we empathize humanoid robots and humans in the same way? Behavioral and multimodal brain imaging investigations

Humanoid robots have been designed to look more and more like humans to meet social demands. How do people empathize humanoid robots who look the same as but are essentially different from humans? We addressed this issue by examining subjective feelings, electrophysiological activities, and functional magnetic resonance imaging signals during perception of pain and neutral expressions of faces that were recognized as patients or humanoid robots. We found that healthy adults reported deceased feelings of understanding and sharing of humanoid robots' compared to patients' pain. Moreover, humanoid robot (vs. patient) identities reduced long-latency electrophysiological responses and blood oxygenation level-dependent signals in the left temporoparietal junction in response to pain (vs. neutral) expressions. Furthermore, we showed evidence that humanoid robot identities inhibited a causal input from the right ventral lateral prefrontal cortex to the left temporoparietal junction, contrasting the opposite effect produced by patient identities. These results suggest a neural model of modulations of empathy by humanoid robot identity through interactions between the cognitive and affective empathy networks, which provides a neurocognitive basis for understanding human-robot interactions.

From Parental Behavior to Sexual Function: Recent Advances in Oxytocin Research

Purpose of Review

Oxytocin plays many diverse roles in physiological and behavioral processes, including social activity, parental nurturing, stress responses, and sexual function. In this narrative review, we provide an update on the most noteworthy recent findings in this fascinating field.

Recent Findings

The development of techniques such as serial two-photon tomography and fiber photometry have provided a window into oxytocin neuroanatomy and real-time neuronal activity during social interactions. fMRI and complementary mapping techniques offer new insights into oxytocin's influence on brain activity and connectivity. Indeed, oxytocin has recently been found to influence the acquisition of maternal care behaviors and to mediate the influence of social touch on brain development and social interaction. Additionally, oxytocin plays a crucial role in male sexual function, affecting erectile activity and ejaculation, while its role in females remains controversial. Recent studies also highlight oxytocin's interaction with other neuropeptides, such as melanin-concentrating hormone, serotonin, and arginine vasopressin, influencing social and affective behaviors. Finally, an update is provided on the status of clinical trials involving oxytocin as a therapeutic intervention.

Summary

The exploration of oxytocin's complexities and its interplay with other neuropeptides holds promise for targeted treatment in various health and disease contexts. Overall, these findings contribute to the discovery of new and specific pathways to allow therapeutic targeting of oxytocin to treat disorders.

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.

Oxytocin modulates neural activity during early perceptual salience attribution

Leading hypotheses of oxytocin's (OT) role in human cognition posit that it enhances salience attribution. However, whether OT exerts its effects predominantly in social (vs non-social) contexts remains debatable, and the time-course of intranasal OT's effects' on salience attribution processing is still unknown. We used the social Salience Attribution Task modified (sSAT) in a double-blind, placebo-controlled intranasal OT (inOT) administration, between-subjects design, with 54 male participants, to test existing theories of OT's role in cognition. Namely, we aimed to test whether inOT would differently affect salience attribution processing of social stimuli (expressing fearfulness) and non-social stimuli (fruits) made relevant via monetary reinforcement, and its neural processing time-course. During electroencephalography (EEG) recording, participants made speeded responses to emotional social (fearful faces) and non-emotional non-social (fruits) stimuli - which were matched for task-relevant motivational salience through their (color-dependent) probability of monetary reinforcement. InOT affected early (rather than late, P3b and LPP) EEG components, increasing N170 amplitude (p = .041) and P2b latency (p .001; albeit not of P1), regardless of stimuli's (emotional) socialness or reinforcement probability. Fear-related socialness affected salience attribution processing EEG (p .05) across time (N170, P2b and P3b), being later modulated by reinforcement probability (LPP). Our data suggest that OT's effects on neural activity during early perception, may exist irrespective of fear-related social- or reward-contexts. This partially supports the tri-phasic model of OT (which posits OT enhances salience attribution in an early perception stage regardless of socialness), and not the social salience nor the general approach-withdrawal hypotheses of OT, for early salience processing event-related potentials.

Temporal Unfolding of Racial Ingroup Bias in Neural Responses to Perceived Dynamic Pain in Others

In this study, we investigated how empathic neural responses unfold over time in different empathy networks when viewing same-race and other-race individuals in dynamic painful conditions. We recorded magnetoencephalography signals from Chinese adults when viewing video clips showing a dynamic painful (or non-painful) stimulation to Asian and White models' faces to trigger painful (or neutral) expressions. We found that perceived dynamic pain in Asian models modulated neural activities in the visual cortex at 100 ms-200 ms, in the orbitofrontal and subgenual anterior cingulate cortices at 150 ms-200 ms, in the anterior cingulate cortex around 250 ms-350 ms, and in the temporoparietal junction and middle temporal gyrus around 600 ms after video onset. Perceived dynamic pain in White models modulated activities in the visual, anterior cingulate, and primary sensory cortices after 500 ms. Our findings unraveled earlier dynamic activities in multiple neural circuits in response to same-race (vs other-race) individuals in dynamic painful situations.

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.

Creative mindset reduces racial ingroup bias in empathic neural responses

Spontaneous racial categorization of other-race individuals provides a cognitive basis of racial ingroup biases in empathy and prosocial behavior. In two experiments, we investigated whether fostering a creativity mindset reduces racial ingroup biases in empathy and undermines spontaneous racial categorization of other-race faces. Before and after a creative mindset priming procedure that required the construction of novel objects using discreteness, we recorded electroencephalography signals to Asian and White faces with painful or neutral expressions from Chinese adults to assess neural activities underlying racial ingroup biases in empathy and spontaneous racial categorization of faces. We found that a frontal-central positive activity within 200 ms after face onset (P2) showed greater amplitudes to painful (vs. neutral) expressions of Asian compared with White faces and exhibited repetition suppression in response to White faces. These effects, however, were significantly reduced by creative mindset priming. Moreover, the creative mindset priming enhanced the P2 amplitudes to others' pain to a larger degree in participants who created more novel objects. The priming effects were not observed in control participants who copied objects constructed by others. Our findings suggest that creative mindsets may reduce racial ingroup biases in empathic neural responses by undermining spontaneous racial categorization of faces.

The relationship between oxytocin and empathy for others' pain: Testing the mediating effect of first-hand pain sensitivity

Although previous studies have shown that oxytocin attenuates first-hand pain sensitivity, studies of its effects on empathic reactions to the observation of others' pain have yielded inconsistent and controversial results. Given the link between first-hand pain and empathy for others' pain, we hypothesized that oxytocin affects empathy for others' pain by modulating first-hand pain sensitivity. Using a double-blind, placebo-controlled, between-participant experimental design, healthy participants (n = 112) were randomly assigned to either an intranasal oxytocin or placebo group. Pain sensitivity was evaluated by pressure pain threshold, and empathic responses were assessed by ratings in response to viewing video clips depicting others in physically painful scenarios. Results showed that pressure pain thresholds decreased over time in both groups, indicating increased sensitivity to first-hand pain after repeated measurements. However, this decrease was smaller for participants who received intranasal oxytocin, indicative of oxytocin-induced attenuation of first-hand pain sensitivity. In addition, although empathic ratings were comparable between oxytocin and placebo groups, first-hand pain sensitivity fully mediated the impact of oxytocin on pain empathetic ratings. Thus, intranasal oxytocin can indirectly affect pain empathic ratings by reducing first-hand pain sensitivity. These findings expand our understanding of the relationship among oxytocin, pain, and empathy.

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.

From Oxytocin to Compassion: The Saliency of Distress

Compassion is a warm response of care and concern for those who are suffering, which drives individuals to devote their resources for the sake of others. A prominent neuroevolutionary framework grounds compassion in the neurobiology of the mammalian caregiving system. Accordingly, it has been suggested that the oxytocinergic system, which plays a central role in parental caregiving and bonding, provides the neurobiological foundation for compassion towards strangers. Yet, the specific role of oxytocin in compassion is far from clear. The current paper aims to target this gap and offer a theoretical framework that integrates the state-of-the-art literature on oxytocin with research on compassion. We suggest that oxytocin mediates compassion by enhancing the saliency of cues of pain and distress and discuss the plausible underlying neurobiological substrates. We further demonstrate how the proposed framework can account for individual differences in compassion, focusing on the effects of attachment on caregiving and support. The proposed framework integrates the current scientific understanding of oxytocin function with compassion-related processes. It thus highlights the largely ignored attentional processes in compassion and taps into the vast variability of responses in social contexts involving pain and suffering.

The effects of intranasal oxytocin on black participants’ responses to outgroup acceptance and rejection

Social acceptance (vs. rejection) is assumed to have widespread positive effects on the recipient; however, ethnic/racial minorities often react negatively to social acceptance by White individuals. One possibility for such reactions might be their lack of trust in the genuineness of White individuals’ positive evaluations. Here, we examined the role that oxytocin—a neuropeptide putatively linked to social processes—plays in modulating reactions to acceptance or rejection during interracial interactions. Black participants (N = 103) received intranasal oxytocin or placebo and interacted with a White, same-sex stranger who provided positive or negative social feedback. After positive feedback, participants given oxytocin (vs. placebo) tended to display approach-oriented cardiovascular responses of challenge (vs. threat), exhibited more cooperative behavior, and perceived the partner to have more favorable attitudes toward them after the interaction. Following negative feedback, oxytocin reduced anger suppression. Oxytocin did not modulate testosterone reactivity directly, but our exploratory analysis showed that the less participants suppressed anger during the interaction with their partner, the greater testosterone reactivity they displayed after the interaction. These results survived the correction for multiple testing with a false discovery rate (FDR) of 20%, but not with a rate of 10 or 5%. Discussion centers on the interplay between oxytocin and social context in shaping interracial interactions.

Racial outgroup favoritism in neural responses to others' pain emerges during sociocultural interactions

Racial ingroup favoritism in empathic brain activity has been widely observed and is associated with biased behavior toward same-race and other-race individuals. We investigated whether racial outgroup favoritism in neural responses to others' pain - an objective measure of empathy - may emerge during sociocultural interactions in a new social environment. We recorded magnetoencephalography to pain and neutral expressions of Asian and White faces from White students who had stayed in China for 6-36 weeks (Experimental group) or 2-4 weeks (Control group). The experimental group showed better neural decoding of and greater insular/sensorimotor responses to pain vs. neutral expressions of Asian compared to White faces. By contrast, the control group showed better neural decoding of pain vs. neutral expressions of White than Asian faces. In addition, participants of the experimental group who had stayed longer in China showed greater sensorimotor responses to pain (vs. neutral) expressions of Asian faces but weaker sensorimotor responses to pain (vs. neutral) expressions of White faces. Our findings revealed emerging racial outgroup favoritism in brain activities associated with sensorimotor resonance and affective sharing of others' pain during sociocultural interactions.

Oxytocin has 'tend-and-defend' functionality in group conflict across social vertebrates

Across vertebrate species, intergroup conflict confronts individuals with a tension between group interests best served by participation in conflict and personal interest best served by not participating. Here, we identify the neurohormone oxytocin as pivotal to the neurobiological regulation of this tension in distinctly different group-living vertebrates, including fishes, birds, rodents, non-human primates and humans. In the context of intergroup conflict, a review of emerging work on pro-sociality suggests that oxytocin and its fish and birds homologues, isotocin and mesotocin, respectively, can elicit participation in group conflict and aggression. This is because it amplifies (i) concern for the interests of genetically related or culturally similar ‘in-group’ others and (ii) willingness to defend against outside intruders and enemy conspecifics. Across a range of social vertebrates, oxytocin can induce aggressive behaviour to ‘tend-and-defend’ the in-group during intergroup contests.

This article is part of the theme issue ‘Intergroup conflict across taxa’.

Exploring gene-culture coevolution in humans by inferring neuroendophenotypes: A case study of the oxytocin receptor gene and cultural tightness

The gene-culture coevolution (GCC) framework has gained increasing prominence in the social and biological sciences. While most studies on human GCC concern the evolution of low-level physiological traits, attempts have also been made to apply GCC to complex human traits, including social behavior and cognition. One major methodological challenge in this endeavor is to reconstruct a specific biological pathway between the implicated genes and their distal phenotypes. Here, we introduce a novel approach that combines data on population genetics and expression quantitative trait loci to infer the specific intermediate phenotypes of genes in the brain. We suggest that such "neuroendophenotypes" will provide more detailed mechanistic insights into the GCC process. We present a case study where we explored a GCC dynamics between the oxytocin receptor gene (OXTR) and cultural tightness-looseness. By combining data from the 1000 Genomes project and the Gene-Tissue-Expression project (GTEx), we estimated and compared OXTR expression in 10 brain regions across five human superpopulations. We found that OXTR expression in the anterior cingulate cortex (ACC) was highly variable across populations, and this variation correlated with cultural tightness and socio-ecological threats worldwide. The mediation models also suggested possible GCC dynamics where the increased OXTR expression in the ACC mediates or emerges from the tight culture and higher socio-ecological threats. Formal selection scans further confirmed that OXTR alleles linked to enhanced receptor expression in the ACC underwent positive selection in East Asian countries with tighter social norms. We discuss the implications of our method in human GCC research.

Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic-pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body's regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.

The influence of social pain experience on empathic neural responses: the moderating role of gender

Empathy for pain, the ability to share and understand the pain of others, plays an important role in the survival and development of individuals. Previous studies have found that social pain experience affects empathy for pain, but potential gender differences have not been considered. The stage of information processing during which gender is most likely to play a moderating role has yet to be clarified. In the current study, we set up two groups (social pain experience priming: social exclusion group; positive social interaction experience priming: social inclusion group) with a Cyberball game paradigm. We recorded the electrophysiological responses when participants were completing an empathy task. An early frontal P2 and N2 differentiation between painful stimuli and neutral stimuli was observed and females showed larger P2 amplitudes than males. At the P3 stage, in the social exclusion group, males showed similar parietal P3 amplitudes for painful and neutral stimuli, while females showed smaller P3 amplitudes for painful stimuli. At the central-parietal late positive potential (LPP) stage, females in the social inclusion group showed larger LPP amplitudes for painful stimuli than males. Our results suggest that gender plays a significant moderating role in how social pain experience affects empathy for pain during the late cognitive processing stage. Experiment 2 was designed to investigate the cognitive mechanism behind the results for the P3 component in females and the results partially confirmed our speculation. This study provides a neurophysiological basis for the dynamic gender differences in the effects of social pain experience on empathy for pain.

Increased activation in the bilateral anterior insulae in response to others in pain in mothers compared to non-mothers

Empathy allows us to share emotions and encourages us to help others. It is especially important in the context of parenting where children's wellbeing is dependent on their parents' understanding and fulfilment of their needs. To date, little is known about differences in empathy responses of parents and non-parents. Using stimuli depicting adults and children in pain, this study focuses on the interaction of motherhood and neural responses in areas associated with empathy. Mothers showed higher activation to both adults and children in pain in the bilateral anterior insulae, key regions of empathy for pain. Additionally, mothers more strongly activated the inferior frontal, superior temporal and the medial superior frontal gyrus. Differences between adult and child stimuli were only found in occipital areas in both mothers and non-mothers. Our results suggest a stronger neural response to others in pain in mothers than non-mothers regardless of whether the person is a child or an adult. This could indicate a possible influence of motherhood on overall neural responses to others in pain rather than motherhood specifically shaping child-related responses. Alternatively, stronger responses to others in pain could increase the likelihood for women to be in a relationship and subsequently to have a child.

The residential stability mindset increases racial in-group bias in empathy

With the deepening of internationalization, the population's mobility has greatly increased, which can impact people's intergroup relationships. The current research examined the hypothesis that residential mobility plays a crucial role in racial in-group bias in empathy (RIBE) with three studies. By manipulating the residential mobility/stability mindset and measuring subjective pain intensity ratings (Study 1) and event-related potentials (ERPs, Study 2) of Chinese adults on painful and neutral expressions of Asian and Caucasian faces, we found that the RIBE in subjective ratings and N1 amplitudes increased and P3 amplitudes decreased in the stability group. Transcranial direct current stimulation (tDCS) manipulation in Study 3 further found that anodal stimulation of the left dorsolateral prefrontal cortex (DLPFC) increased the RIBE of participants with residential stability experience but had no effect on those with residential mobility experience. As residential mobility continues to increase worldwide, we may observe concomitant changes in racial intergroup relationships.

Effects of Oxytocin on Social Comparisons in Intergroup Situations

Oxytocin (OXT) is known to affect various social processes, including social comparisons and intergroup competition. In this study, we examined whether social comparisons in intergroup situations can be modulated by OXT and, if so, how this modulation manifests. Using a double-blind placebo-controlled design, we randomly assigned male participants to either OXT or placebo treatment and then asked them to play a card game with either an in-group or an out-group member. The OXT-treated participants showed a greater social comparison effect in the games with an out-group member than in games with an in-group member. Specifically, the participants in the OXT treatment condition showed a greater acceptance rate for relative gain (downward comparison) and a lower acceptance rate for relative loss (upward comparison) while playing with an out-group member rather than an in-group member. In contrast, no such effect was observed among placebo-treated participants. These findings demonstrate that OXT facilitates intergroup social comparisons with out-group versus in-group members.

Oxytocin Modulates Neural Individuation/Categorization Processing of Faces in Early Face-Selective Areas

Oxytocin (OT) is known as a neuropeptide that promotes social adaptation. Individuating racial in-group members and viewing racial out-groups in categories is an adaptive strategy that evolved to aid effective social interaction. Nevertheless, whether OT modulates the neural individuation/categorization processing of racial in-group and out-group faces remain unknown. After intranasal OT or placebo administration, 46 male participants (OT: 24, placebo: 22) were presented with face pairs with the same or different identities or races in rapid succession. The neural repetition suppression (RS) effects to identity and race were measured using functional magnetic resonance imaging (fMRI) as indices of individuation/categorization face-processing. The results showed that while OT increased the RS effect to race, it decreased the RS effect to identity in the right fusiform face area. As for the left occipital face area, OT enlarged the differential RS effects to identities of in-group and out-group faces. Additionally, OT modulated the association of interdependence self-construal and the RS effects on identity and race. These findings bring to light preliminary evidence that OT can regulate neuronal specificity of identity and race in early face-selective regions and benefit adaptive individuation/categorization face-processing.

Neural mechanisms of modulations of empathy and altruism by beliefs of others' pain

Perceived cues signaling others' pain induce empathy which in turn motivates altruistic behavior toward those who appear suffering. This perception-emotion-behavior reactivity is the core of human altruism but does not always occur in real-life situations. Here, by integrating behavioral and multimodal neuroimaging measures, we investigate neural mechanisms underlying modulations of empathy and altruistic behavior by beliefs of others' pain (BOP). We show evidence that lack of BOP reduces subjective estimation of others' painful feelings and decreases monetary donations to those who show pain expressions. Moreover, lack of BOP attenuates neural responses to their pain expressions within 200 ms after face onset and modulates neural responses to others' pain in the insular, post-central, and frontal cortices. Our findings suggest that BOP provide a cognitive basis of human empathy and altruism and unravel the intermediate neural mechanisms.

Processing of facial expressions of same-race and other-race faces: distinct and shared neural underpinnings

People understand others’ emotions quickly from their facial expressions. However, facial expressions of ingroup and outgroup members may signal different social information and thus be mediated by distinct neural activities. We investigated whether there are distinct neuronal responses to fearful and happy expressions of same-race (SR) and other-race (OR) faces. We recorded electroencephalogram from Chinese adults when viewing an adaptor face (with fearful/neutral expressions in Experiment 1 but happy/neutral expressions in Experiment 2) and a target face (with fearful expressions in Experiment 1 but happy expressions in Experiment 2) presented in rapid succession. We found that both fearful and happy (vs neutral) adaptor faces increased the amplitude of a frontocentral positivity (P2). However, a fearful but not happy (vs neutral) adaptor face decreased the P2 amplitudes to target faces, and this repetition suppression (RS) effect occurred when adaptor and target faces were of the same race but not when of different races. RS was observed on two late parietal/central positive activities to fearful/happy target faces, which, however, occurred regardless of whether adaptor and target faces were of the same or different races. Our findings suggest that early affective processing of fearful expressions may engage distinct neural activities for SR and OR faces.

Associations between oxytocin and empathy in humans: A systematic literature review

This is a systematic review about the association between empathic behavior and oxytocin (OXT). Searches were conducted in the electronic databases PubMed, Web of Science, PsycINFO, SciELO, and LILACS using the search terms "oxytocin", "empathy", and "empathic". Forty-four studies were reviewed. Scarce findings point to a lack of association between baseline endogenous OXT levels and empathy traits, and for a trend towards a direct relationship between oxytocinergic reactivity and empathic functioning. The results showed that variations in empathy were related to polymorphisms in the OXT receptor gene, especially in rs53576, and that this relationship seems to mediated by individual, ethnic, and cultural characteristics. Most studies on the exogenous administration of OXT tested a single dose (24 IU) with positive effects mainly on the affective domain of empathy. At the neural level, findings were inconsistent. Taken together, the results of the studies reviewed support the existence of a relationship between OXT and empathy that is complex and multifaceted. Robust evidence is still needed to elucidate existing links. Future investigations could benefit from methodological improvements aimed at increasing the reproducibility and applicability of findings, as well as the systematic assessment of the effects of exogenous OXT considering dose and frequency of administration, genotyping, and hormonal availability at the peripheral and central levels. This should lead to significant progress in the understanding of the therapeutic possibilities of OXT in the domain of empathic behavior.

Empathy-based tolerance towards poor norm violators in third-party punishment

Third-party punishment (TPP) plays an important role in fairness norm enforcement. This study investigated how the economic status of proposers could modulate third parties' behavioural and neural responses to unfairness. Participants played a TPP game as third parties deciding whether to punish proposers after observing the offers from proposers while behavioural and electroencephalogram (EEG) data were recorded. The proposers were of either high economic status or low economic status, and the recipients were middle class. The behavioural results indicated that participants reported decreased punishment for poor-proposed unfair offers compared to rich-proposed unfair offers, and this effect was stronger for highly unfair offers. Neurally, greater P200, a component involved in empathy processing, was observed in response to highly unfair offers (i.e. 90:10 and 80:20) proposed by the poor, suggesting that when the targets of severe punishments were poor proposers, participants showed greater empathy for poor norm violators in highly unfair trials. Taken together, these findings help to elucidate that the third-parties tend to tolerate the norm-violating behaviours conducted by the poor and provided further neuroscience evidence for the influence of economic status of proposers on TPP.

Intranasal oxytocin decreases self-oriented learning

RATIONALE

Oxytocin has been found to play an important role in human social cognition and social interaction. Over the last two decades, surge studies have been conducted to investigate how oxytocin impacts other-oriented processes, such as trust and generosity (Zak et al. in PLoS ONE 2(11):e1128, 2007); however, the examination of the effect of oxytocin on self-related processes was relatively inadequate. Appropriate and efficient social interactions require both self- and other-related information processing. Recent studies have found that intranasal oxytocin (IN-OT) influences the self-related process, although the results have been mixed. The computational process underlying the effects of IN-OT on self-processing remains unknown.

OBJECTIVES

We aim to investigate the effect of IN-OT on self-oriented learning across different contexts (self-other independent vs. self-other dependent) and uncover the process by which IN-OT affects dynamic behavior changes.

METHODS

We performed two double-blind, placebo-controlled studies and used reinforcement learning theory to integrate action and related feedback for participants' behaviors.

RESULTS

In study 1, IN-OT decreased self-oriented reward learning when self-oriented learning and prosocial (other-oriented) learning were assessed separately. These effects were partially due to the OT-related increase in choice variability during self-oriented learning. In study 2, IN-OT also decreased learning performance during self-oriented reward learning when self-related and other-related rewards were present together. These effects occurred at an early stage of the learning process and could be moderated by the participants' social value orientation. Our findings show that OT attenuates the process of self-oriented learning and provides an underlying computational process.

CONCLUSIONS

Our findings shed new light on the dynamics of IN-OT's effects on human self-oriented learning processes. For future studies on OT effects on self-oriented learning, individual factors such as social value orientation should be taken into consideration in research development and analysis.

The Role of Intranasal Oxytocin on Social Cognition: An Integrative Human Lifespan Approach

PURPOSE OF REVIEW

This narrative review synthesizes research from the last two decades on the modulatory role of intranasal OT administration (IN-OT) on social cognition in early life, young/middle adulthood, and older adulthood. Advances and knowledge gaps are identified, and future research directions are discussed within an integrative human lifespan framework to guide novel research on IN-OT and social cognition.

RECENT FINDINGS

Current evidence regarding IN-OT modulation of social-cognitive processes, behavior, and related neurocircuitry is mixed, with some studies suggesting benefits (e.g., improved social perception/interactions, emotion processing) depending on contextual (e.g., social stimuli) and interindividual factors (e.g., age, sex, clinical status). Current research, however, is limited by a focus on isolated life phases, males, and select clinical populations as well as a lack of standardized protocols.

SUMMARY

This literature-based reflection proposes that greater generalizability of findings and scientific advancement on social-cognitive modulation via IN-OT require standardized, multi-method, longitudinal, and cross-sequential assessments in well-powered, well-controlled, and representative samples in line with an integrative lifespan approach, which considers development as a lifelong dynamic process involving both change and stability characterized by the interplay between genetic, neurobiological, and socio-behavioral factors.

Effect of intranasal oxytocin administration on self-other distinction: Modulations by psychological distance and gender

Preliminary evidence indicates that intranasal oxytocin (OT) administration modulates one's ability to distinguish oneself from others (i.e., self-other distinction). However, previous findings on this topic are contradictory. The current study addressed this issue by (i) using a novel perceptual matching task examining self-other distinction compared to both close and distant others, and (ii) tentatively exploring potential modulations by gender. In a double-blind, placebo-controlled, randomized OT administration study, 100 participants (50 males and 50 females) were randomized to receive intranasal spray of 24 IU OT or placebo (PL). Afterwards, participants completed a geometry perceptual matching task in which different shapes were paired to the self, a friend, or a stranger. Participants were then asked to judge whether each pair of shapes and labels was correctly matched. The results revealed that compared to PL administration, OT facilitated distinction between the self and a friend in males but not in females. These findings provide insights for debates on the role of OT in self-other distinction by revealing modulations by psychological distance and gender, which have implications for the potential clinical applications of OT.

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.

Tri-Phasic Model ofOxytocin (TRIO): A systematic conceptual review of oxytocin-related ERP research

BACKGROUND

The neuropeptide oxytocin (OT) has been shown to play a role in variety of cognitive and social processes and different hypotheses have been put forth to explain OT's effects on brain and behavior in humans. However, these previous explanatory accounts do not provide information about OT-related temporal modulation in the brain.

OBJECTIVES

This paper systematically reviewed intranasal OT administration studies employing event-related potentials (ERPs) and synthesized the existing evidence into a novel conceptual framework.

METHODS

Empirical studies, published until February 2020 and cited in major databases (EBSCOhost, PubMed, and Web of Science), were examined in accordance with PRISMA guidelines. To be included, studies had to: (i) employ intranasal administration of OT, as the chemical modulator; (ii) measure ERPs; (iii) be peer-reviewed journal articles; (iv) be written in English; and (v) examine human participants.

RESULTS

The search criteria yielded 17 empirical studies. The systematic review resulted in conceptualization of the Tri-Phasic Model ofOxytocin (TRIO), which builds on three processing stages: (i) perception, (ii) selection, and (iii) evaluation. While OT increases attention irrespective of stimuli characteristics in the perception stage, in the selection and evaluation stages, OT acts as a filter to guide attention selectively towards social over non-social stimuli and modulates prosociality/approach motivation associated with social stimuli.

CONCLUSIONS

TRIO offers an empirically-derived conceptual framework that can guide the study of OT-related modulation on attentional processes, starting very early in the processing stream. This novel account furthers theoretical understanding and informs empirical investigation into OT modulation on the brain.

Oxytocin increases the social salience of the outgroup in potential threat contexts

A growing body of literature suggests that OT administration may affect not only prosocial outcomes, but also regulate adversarial responses in the context of intergroup relations. However, recent reports have challenged the view of a fixed role of OT in enhancing ingroup favoritism and outgroup derogation. Studying the potential effects of OT in modulating threat perception in a context characterized by racial miscegenation (Brazil) may thus afford additional clarification on the matter. In a double-blind, placebo-controlled study, White Brazilian participants completed a first-person shooter task to assess their responses towards potential threat from racial ingroup (White) or outgroup (Black) members. OT administration enhanced the social salience of the outgroup, by both increasing the rate at which participants refrained from shooting unarmed Black targets to levels similar to White targets, and by further increasing the rate of correct decisions to shoot armed Black targets (versus White armed targets). In summary, our results indicate that a single dose of OT may promote accurate behavioral responses to potential threat from members of a racial outgroup, thus offering support to the social salience hypothesis.

A Novel Role of CD38 and Oxytocin as Tandem Molecular Moderators of Human Social Behavior

Oxytocin is an important modulator of human affiliative behaviors, including social skills, human pair bonding, and friendship. CD38 will be discussed as an immune marker and then in more detail the mechanisms of CD38 on releasing brain oxytocin. Mention is made of the paralogue of oxytocin, vasopressin, that has often overlapping and complementary functions with oxytocin on social behavior. Curiously, vasopressin does not require CD38 to be released from the brain. This review discusses the social salience hypothesis of oxytocin action, a novel view of how this molecule influences much of human social behaviors often in contradictory ways. The oxytocinergic-vasopressinergic systems are crucial modulators of broad aspects of human personality. Of special interest are studies of these two hormones in trust related behavior observed using behavioral economic games. This review also covers the role of oxytocin in parenting and parental attachment. In conclusion, the effects of oxytocin on human behavior depend on the individual's social context and importantly as well, the individual's cultural milieu, viz. East and West. ACRONYMS: ACC = Anterior Cingulate ADP = Adenosine diphosphate AQ = Autism Quotient cADPR = Cyclic ADP-ribose CNS = Central nervous system DA = Dopamine eQTLC = Expression Quantitative Trait Loci LC-NE = Locus Coeruleus-Norepinephrine MRI = Magnetic Resonance Imaging OFC = Orbitofrontal cortices OXT = Oxytocin RAGE = Receptor for advanced glycation end-products SARM1 = Sterile Alpha and toll/interleukin-1 receptor motif-containing 1 TRPM2= Transient Receptor Potential Cation Channel Subfamily M Member 2 AVP = Vasopressin.

A neurobiological association of revenge propensity during intergroup conflict

Revenge during intergroup conflict is a human universal, but its neurobiological underpinnings remain unclear. We address this by integrating functional MRI and measurements of endogenous oxytocin in participants who view an ingroup and an outgroup member's suffering that is caused mutually (Revenge group) or by a computer (Control group). We show that intergroup conflict encountered by the Revenge group is associated with an increased level of oxytocin in saliva compared to that in the Control group. Furthermore, the medial prefrontal activity in response to ingroup pain in the Revenge group but not in the Control group mediates the association between endogenous oxytocin and the propensity to give painful electric shocks to outgroup members, regardless of whether they were directly involved in the conflict. Our findings highlight an important neurobiological correlate of revenge propensity, which may be implicated in conflict contagion across individuals in the context of intergroup conflict.

Oxytocin changes behavior and spatio-temporal brain dynamics underlying inter-group conflict in humans

Inter-group conflicts drive human discrimination, mass migration, and violence, but their psychobiological mechanisms remain largely unknown. Here, we investigated whether the neuropeptide oxytocin modulates behavior and spatio-temporal brain dynamics in naturalistic inter-group conflict. Eighty-six male members of natural rival social groups received either oxytocin or placebo intranasally. In a decision-making paradigm involving real monetary stakes, participants could sacrifice their own resources to modulate the monetary gains and losses of in- and out-group members. Oxytocin eliminated the reduction in out-group gains - particularly in individuals with low emotional empathy, whereas those given placebo exhibited this negative social behavior. Our spatio-temporal analysis of event-related potentials elicited by outcome valuation revealed that oxytocin replaced a neurophysiological process associated with the negative valuation of out-group gains via a process associated with positive valuation between 200-500ms after outcome presentation. Oxytocin thus seems to modulate inter-group behavior in humans via a specific alteration of valuation-related brain dynamics.

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.

The effect of emotional information from eyes on empathy for pain: A subliminal ERP study

Facial expressions are deeply tied to empathy, which plays an important role during social communication. The eye region is effective at conveying facial expressions, especially fear and sadness emotions. Further, it was proved that subliminal stimuli could impact human behavior. This research aimed to explore the effect of subliminal sad, fearful and neutral emotions conveyed by the eye region on a viewer's empathy for pain using event-related potentials (ERP). The experiment used an emotional priming paradigm of 3 (prime: subliminal neutral, sad, fear eye region information) × 2 (target: painful, nonpainful pictures) within-subject design. Participants were told to judge whether the targets were in pain or not. Results showed that the subliminal sad eye stimulus elicited a larger P2 amplitude than the subliminal fearful eye stimulus when assessing pain. For P3 and late positive component (LPC), the amplitude elicited by the painful pictures was larger than the amplitude elicited by the nonpainful pictures. The behavioral results demonstrated that people reacted to targets depicting pain more slowly after the sad emotion priming. Moreover, the subjective ratings of Personal Distress (PD) (one of the dimensions in Chinese version of Interpersonal Reactivity Index scale) predicted the pain effect in empathic neural responses in the N1 and N2 time window. The current study showed that subliminal eye emotion affected the viewer's empathy for pain. Compared with the subliminal fearful eye stimulus, the subliminal sad eye stimulus had a greater impact on empathy for pain. The perceptual level of pain was deeper in the late controlled processing stage.

Brain pathways of pain empathy activated by pained facial expressions: a meta-analysis of fMRI using the activation likelihood estimation method

OBJECTIVE:

The objective of this study is to summarize and analyze the brain signal patterns of empathy for pain caused by facial expressions of pain utilizing activation likelihood estimation, a meta-analysis method.

DATA SOURCES:

Studies concerning the brain mechanism were searched from the Science Citation Index, Science Direct, PubMed, DeepDyve, Cochrane Library, SinoMed, Wanfang, VIP, China National Knowledge Infrastructure, and other databases, such as SpringerLink, AMA, Science Online, Wiley Online, were collected. A time limitation of up to 13 December 2016 was applied to this study.

DATA SELECTION:

Studies presenting with all of the following criteria were considered for study inclusion: Use of functional magnetic resonance imaging, neutral and pained facial expression stimuli, involvement of adult healthy human participants over 18 years of age, whose empathy ability showed no difference from the healthy adult, a painless basic state, results presented in Talairach or Montreal Neurological Institute coordinates, multiple studies by the same team as long as they used different raw data.

OUTCOME MEASURES:

Activation likelihood estimation was used to calculate the combined main activated brain regions under the stimulation of pained facial expression.

RESULTS:

Eight studies were included, containing 178 subjects. Meta-analysis results suggested that the anterior cingulate cortex (BA32), anterior central gyrus (BA44), fusiform gyrus, and insula (BA13) were activated positively as major brain areas under the stimulation of pained facial expression.

CONCLUSION:

Our study shows that pained facial expression alone, without viewing of painful stimuli, activated brain regions related to pain empathy, further contributing to revealing the brain’s mechanisms of pain empathy.

The Effects of Same- and Other-Race Facial Expressions of Pain on Temporal Perception

Previous studies suggested that threatening stimuli lengthen subjective duration, while facial expressions of pain were found to produce a shortening effect on temporal perception in a recent study. Moreover, individuals' responses to others' pain were influenced by the individuals' relationship to a racial group. However, the effects of same- and other-race pained facial expressions on temporal perception, remain unknown. The aim of this present study was to identify the effect expressions of pain have on temporal perception and to explore whether this effect was modulated by the relationship to a racial group. In a temporal bisection task, Chinese participants were presented with pain or neutral facial expressions displayed by Caucasian (other-race) or Chinese (same-race) models in a 400-1600 ms or 200-800 ms condition. Expressions of pain were rated as more arousing, negative and disagreeable, than neutral facial expressions. These scores were not significantly different between same- and other-race facial expressions. Based on the results of the temporal bisection task, both same- and other-race pained facial expressions lengthened the perceived duration in the 400-1600 ms condition, but only same-race pained facial expressions produced this effect in the 200-800 ms condition. We postulate that the existence of a short-lived effect of pained facial expressions on lengthening temporal perception caused by arousal and attention, occurs at an earlier time point for same-race pained facial expressions than for other-race pained facial expressions.

Oxytocin Facilitates Approach Behavior to Positive Social Stimuli via Decreasing Anterior Insula Activity

BACKGROUND

The neuropeptide oxytocin can extensively modulate human social behavior and affective processing, and its effects can be interpreted in terms of mediating approach-avoidance motivational processes. However, little is known about how oxytocin mediates approach-avoidance behavior and particularly the underlying neural mechanisms.

METHODS

In a randomized, double-blind, between-subject design, the present pharmaco-fMRI study used an approach-avoidance paradigm to investigate oxytocin's effects on approach-avoidance behavior and associated neural mechanisms.

RESULTS

Results revealed that oxytocin generally decreased activity in the right striatum irrespective of response (approach/avoidance) and social context, suggesting an inhibitory effect on motivational representation during both appetitive approach and aversive avoidance. Importantly, while on the behavioral level oxytocin selectively enhanced accuracy when approaching social positive stimuli, on the neural level it decreased left ventral and right dorsal anterior insula activity in response to social vs nonsocial positive stimuli compared with the placebo treatment. The left ventral anterior insula activity was negatively correlated with the corresponding accuracy difference scores in the oxytocin but not in the placebo group.

CONCLUSION

Given the role of the ventral anterior insula in emotional processing and the dorsal anterior insula in salience processing, the oxytocin-induced suppression of activity in these regions may indicate that oxytocin is acting to reduce interference from hyper-activity in core regions of the emotional and salience networks when approaching salient positive social stimuli and thereby to promote social interaction. Thus, oxytocin may be of potential therapeutic benefit for psychiatric disorders exhibiting avoidance of social stimuli.

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.

Oxytocin effects on self-referential processing: behavioral and neuroimaging evidence

Oxytocin (OT) influences other-oriented mental processes (e.g. trust and empathy) and the underlying neural substrates. However, whether and how OT modulates self-oriented processes and the underlying brain activity remains unclear. Using a double-blind, placebo-controlled between-subjects design, we manipulated memory encoding and retrieval of trait adjectives related to the self, a friend and a celebrity in a self-referential task in male adults. Experiment 1 (N = 51) found that OT vs placebo treatments reduced response times during encoding self-related trait adjectives but increased recognition scores of self-related information during memory retrieval. Experiment 2 (N = 50) showed similar OT effects on response times during encoding self-related trait adjectives. Moreover, functional magnetic resonance imaging (fMRI) results revealed that OT vs placebo treatments decreased the activity in the medial prefrontal cortex (MPFC) involved in encoding of self-related trait adjectives and weakened the coupling between the MPFC activity and a cultural trait (i.e. interdependence). Experiment 3 (N = 52) revealed that OT vs placebo treatments increased the right superior frontal activity during memory retrieval of self-related information. The results provide behavioral and fMRI evidence for OT effects on self-referential processing and suggest distinct patterns of OT modulations of brain activities engaged in encoding and retrieval of self-related information.

Psychopathy to Altruism: Neurobiology of the Selfish-Selfless Spectrum

The age-old philosophical, biological, and social debate over the basic nature of humans as being “universally selfish” or “universally good” continues today highlighting sharply divergent views of natural social order. Here we analyze advances in biology, genetics and neuroscience increasing our understanding of the evolution, features and neurocircuitry of the human brain underlying behavior in the selfish–selfless spectrum. First, we examine evolutionary pressures for selection of altruistic traits in species with protracted periods of dependence on parents and communities for subsistence and acquisition of learned behaviors. Evidence supporting the concept that altruistic potential is a common feature in human populations is developed. To go into greater depth in assessing critical features of the social brain, the two extremes of selfish–selfless behavior, callous unemotional psychopaths and zealous altruists who take extreme measures to help others, are compared on behavioral traits, structural/functional neural features, and the relative contributions of genetic inheritance versus acquired cognitive learning to their mindsets. Evidence from population groups ranging from newborns, adopted children, incarcerated juveniles, twins and mindfulness meditators point to the important role of neuroplasticity and the dopaminergic reward systems in forming and reforming neural circuitry in response to personal experience and cultural influences in determining behavior in the selfish–selfless spectrum. The underlying neural circuitry differs between psychopaths and altruists with emotional processing being profoundly muted in psychopaths and significantly enhanced in altruists. But both groups are characterized by the reward system of the brain shaping behavior. Instead of rigid assignment of human nature as being “universally selfish” or “universally good,” both characterizations are partial truths based on the segments of the selfish–selfless spectrum being examined. In addition, individuals and populations can shift in the behavioral spectrum in response to cognitive therapy and social and cultural experience, and approaches such as mindfulness training for introspection and reward-activating compassion are entering the mainstream of clinical care for managing pain, depression, and stress.

Oxytocin promotes intuitive rather than deliberated cooperation with the in-group

A contribution to a special issue on Hormones and Human Competition. In intergroup settings, individuals prefer cooperating with their in-group, and sometimes derogate and punish out-groups. Here we replicate earlier work showing that such in-group bounded cooperation is conditioned by oxytocin and extend it by showing that oxytocin-motivated in-group cooperation is intuitive rather than deliberated. Healthy males (N=65) and females (N=129) self-administered intranasal placebo or 24IU oxytocin in a double-blind placebo-controlled between-subjects design, were assigned to a three-person in-group (that faced a 3-person out-group), and given an endowment from which they could contribute to a within-group pool (benefitting the in-group), and/or to a between-group pool (benefitting the in-group and punishing the out-group). Prior to decision-making, participants performed a Stroop Interference task that was either cognitively taxing, or not. Cognitively taxed individuals kept less to themselves and contributed more to the within-group pool. Furthermore, participants receiving placebo contributed more to the within-group pool when they were cognitively taxed rather than not; those receiving oxytocin contributed to the within-group pool regardless of cognitive taxation. Neither taxation nor treatment influenced contributions to the between-group pool, and no significant sex differences were observed. It follows that in intergroup settings (i) oxytocin increases in-group bounded cooperation, (ii) oxytocin neither reduces nor increases out-group directed spite, and (iii) oxytocin-induced in-group cooperation is independent of cognitive taxation and, therefore, likely to be intuitive rather than consciously deliberated.