Skin Color and Attractiveness Modulate Empathy for Pain: An Event-Related Potential Study

Although racial in-group bias in empathy for pain has been reported, empathic responses to others’ pain may be influenced by other characteristics besides race. To explore whether skin color and attractiveness modulate empathy for pain, we recorded 24 participants’ reactions to painful faces from racial in-group members with different skin color (fair, wheatish, or dark) and attractiveness (more or less attractive) using event-related potentials (ERPs). Results showed that, for more attractive painful faces, dark skin faces were judged as less painful and elicited smaller N2 amplitudes than fair- and wheatish-skinned faces. However, for less attractive faces, there were no significant differences among the three skin colors. Our findings suggest that empathy for pain toward racial in-group members may be influenced by skin color and attractiveness.

Placebo Analgesia Changes on Self-Pain and Empathy for Pain: Influences of Event-Related EEG Oscillations, Heart Rate Variability, and Personality

We induced placebo analgesia (PA), a phenomenon explicitly attenuating the self-pain feeling, to assess whether this resulted in reduced empathy pain when witnessing a confederate undergoing such pain experience. We recorded EEG and electrocardiogram during a painful control and PA treatment in healthy adults who rated their experienced pain and empathy for pain. We derived HRV changes and, using wavelet analysis of non-phase-locked event-related EEG oscillations, EEG spectral power differences for self-pain and other-pain conditions. First-hand PA produced a reduction of self-pain and self-unpleasantness, whereas we observed only a slight decrease of other unpleasantness. We derived linear combinations of HRV and EEG band power changes significantly associated with self-pain and empathy for pain changes using PCAs. We found that relative HR-slowing together with decreased midline ϑ-band (4-8 Hz) power directly influenced self-pain reduction and, indirectly, through chained mediating effects of the Behavioral Inhibition System and Fight-Flight-Freezing System traits. In the other-pain condition, we detected a direct influence of the midline β2-band (22-30 Hz) power reduction on the other-pain decline with a positive mediating role of Total Empathic Ability. These findings suggest that PA modulation of first-hand versus other pain relies on functionally different physiological processes involving different personality traits.

Commanding or being a simple intermediary: how does it affect moral behavior and related brain mechanisms?

History has shown that fractioning operations between several individuals along a hierarchical chain allows diffusing responsibility between components of the chain, which has the potential to disinhibit antisocial actions. Here, we present two studies, one using fMRI (Study 1) and one using EEG (Study 2), designed to help understand how commanding or being in an intermediary position impacts the sense of agency and empathy for pain. In the age of military drones, we also explored whether commanding a human or robot agent influences these measures. This was done within a single behavioral paradigm in which participants could freely decide whether or not to send painful shocks to another participant in exchange for money. In Study 1, fMRI reveals that activation in social cognition and empathy-related brain regions was equally low when witnessing a victim receive a painful shock while participants were either commander or simple intermediary transmitting an order, compared to being the agent directly delivering the shock. In Study 2, results indicated that the sense of agency did not differ between commanders and intermediary, no matter if the executing agent was a robot or a human. However, we observed that the neural response over P3 was higher when the executing agent was a robot compared to a human. Source reconstruction of the EEG signal revealed that this effect was mediated by areas including the insula and ACC. Results are discussed regarding the interplay between the sense of agency and empathy for pain for decision-making.

The gradient model of brain organization in decisions involving 'empathy for pain'

Recent meta-analytic studies of social cognition and the functional imaging of empathy have exposed the overlap between their neural substrates and heteromodal association areas. The 'gradient model' of cortical organization proposes a close relationship between these areas and highly connected hubs in the default mode network, a set of cortical areas deactivated by demanding tasks. Here, we used a decision-making task and representational similarity analysis with classic 'empathy for pain' visual stimuli to probe the relationship between high-level representations of imminent pain in others and the high end of the gradient of this model. High-level representations were found to co-localize with task deactivations or the transitions from activations to deactivations. These loci belonged to two groups: those that loaded on the high end of the principal cortical gradient and were associated by meta-analytic decoding with the default mode network, and those that appeared to accompany functional repurposing of somatosensory cortex in the presence of visual stimuli. In contrast to the nonspecific meta-analytic decoding of these loci, low-level representations, such as those of body parts involved in pain or of pain itself, were decoded with matching topics terms. These findings suggest that that task deactivations may set out cortical areas that host high-level representations, but whose functional characterization in terms of simple mappings is unlikely. We anticipate that an increased understanding of the cortical correlates of high-level representations may improve neurobiological models of social interactions and psychopathology.

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.

Does the cowl make the monk? The effect of military and Red Cross uniforms on empathy for pain, sense of agency and moral behaviors

The present study investigated to what extent the clothes we wear influence prosocial behaviors and two related neuro-cognitive processes, namely the sense of agency and empathy for pain. We tested forty participants wearing civilian, military and Red Cross uniforms across three consecutive days. Participants were tested by pairs and were assigned either to the role of the agent or to the role of the ‘victim’. Agents could deliver real electric shocks to the ‘victim’ in exchange for +€0.05, either following their own decision or following the experimenter’s instructions. Our results indicated that wearing a Red Cross uniform increased the amplitude of the neural response to pain when participants witnessed shocks in comparison with wearing civilian or military clothing. Results also revealed that the sense of agency increased when participants wore a military uniform compared to wearing their own civilian clothing in the Free condition. Finally, participants gave less shocks when wearing the Red Cross uniform compared to wearing their civilian clothing. This study highlights the effect of wearing symbolic uniforms on the sense of agency, on the neural empathic response and on prosocial behavior, thus broadening our knowledge on the impact of ‘enclothed cognition’ on cognitive and psychological processes.

Oxytocin reduces interoceptive influences on empathy-for-pain in the anterior insula

Empathy-for-pain states are underpinned by interoception, i.e the central representation of internal states. Cardiac signals occur in a phasic manner; baroreceptor discharges at systole communicate the heartbeats′ strength. These signals modulate pain and emotion processing. We tested whether these phasic interoceptive signals modulate empathy-for-pain. As oxytocin (OT) enhances empathy and modulates interoceptive signals′ precision, we also tested if OT administration impacts empathy-for-pain via interoceptive mechanisms. Male subjects (N=32) attended three sessions to perform psychometric tests and an fMRI empathy-for-pain task, after intranasal administration of OT or placebo (40IU). Pictures of hands in painful or non-painful context were presented at systole or diastole. Effects of drug, emotion and cardiac timing on behaviour and brain activity was tested using general and mixed-effects linear models. Across conditions, activation was observed within regions implicated in pain and empathy-for-pain, with insula activation greater in the right than left hemisphere. OT administration, compared to placebo, attenuated the reactivity of some regions, including anterior cingulate cortex, but presentation of stimuli at systole blocked the OT attenuating effect. Our data suggest that OT alters the processing of motivationally-salient social cues, interacting with interoceptive signals. Our findings may inform targeted use of OT in psychiatric conditions linked to aberrant interoceptive processing.