Increased similarity of neural responses to experienced and empathic distress in costly altruism

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.

Ethical reasoning versus empathic bias: a false dichotomy?

Does empathy necessarily impede equity in altruism? Emerging findings from cognitive and affective science suggest that rationality and empathy are mutually compatible, contradicting some earlier, prominent arguments that empathy impedes equitable giving. We propose alternative conceptualizations of relationships among empathy, rationality, and equity, drawing on interdisciplinary advances in altruism research.

Healthcare experience affects pain-specific responses to others' suffering in the anterior insula

Medical students and professional healthcare providers often underestimate patients' pain, together with decreased neural responses to pain information in the anterior insula (AI), a brain region implicated in self-pain processing and negative affect. However, the functional significance and specificity of these neural changes remains debated. Across two experiments, we recruited university medical students and emergency nurses to test the role of healthcare experience on the brain reactivity to other's pain, emotions, and beliefs, using both pictorial and verbal cues. Brain responses to self-pain was also assessed and compared with those to observed pain. Our results confirmed that healthcare experience decreased the activity in AI in response to others' suffering. This effect was independent from stimulus modality (pictures or texts), but specific for pain, as it did not generalize to inferences about other mental or affective states. Furthermore, representational similarity and multivariate pattern analysis revealed that healthcare experience impacted specifically a component of the neural representation of others' pain that is shared with that of first-hand nociception, and related more to AI than to other pain-responsive regions. Taken together, our study suggests a decreased propensity to appraise others' suffering as one's own, associated with a reduced recruitment of pain-specific information in AI. These findings provide new insights into neural mechanisms leading to pain underestimation by caregivers in clinical settings.

Neural responses underlying extraordinary altruists' generosity for socially distant others

Most people are much less generous toward strangers than close others, a bias termed social discounting. But people who engage in extraordinary real-world altruism, like altruistic kidney donors, show dramatically reduced social discounting. Why they do so is unclear. Some prior research suggests reduced social discounting requires effortfully overcoming selfishness via recruitment of the temporoparietal junction. Alternatively, reduced social discounting may reflect genuinely valuing strangers' welfare more due to how the subjective value of their outcomes is encoded in regions such as rostral anterior cingulate cortex (ACC) and amygdala. We tested both hypotheses in this pre-registered study. We also tested the hypothesis that a loving-kindness meditation (LKM) training intervention would cause typical adults' neural and behavioral patterns to resemble altruists. Altruists and matched controls (N = 77) completed a social discounting task during functional magnetic resonance imaging; 25 controls were randomized to complete LKM training. Neither behavioral nor imaging analyses supported the hypothesis that altruists' reduced social discounting reflects effortfully overcoming selfishness. Instead, group differences emerged in social value encoding regions, including rostral ACC and amygdala. Activation in these regions corresponded to the subjective valuation of others' welfare predicted by the social discounting model. LKM training did not result in more generous behavioral or neural patterns, but only greater perceived difficulty during social discounting. Our results indicate extraordinary altruists' generosity results from the way regions involved in social decision-making encode the subjective value of others' welfare. Interventions aimed at promoting generosity may thus succeed to the degree they can increase the subjective valuation of others' welfare.

Unselfish traits and social decision-making patterns characterize six populations of real-world extraordinary altruists

Acts of extraordinary, costly altruism, in which significant risks or costs are assumed to benefit strangers, have long represented a motivational puzzle. But the features that consistently distinguish individuals who engage in such acts have not been identified. We assess six groups of real-world extraordinary altruists who had performed costly or risky and normatively rare (<0.00005% per capita) altruistic acts: heroic rescues, non-directed and directed kidney donations, liver donations, marrow or hematopoietic stem cell donations, and humanitarian aid work. Here, we show that the features that best distinguish altruists from controls are traits and decision-making patterns indicating unusually high valuation of others' outcomes: high Honesty-Humility, reduced Social Discounting, and reduced Personal Distress. Two independent samples of adults who were asked what traits would characterize altruists failed to predict this pattern. These findings suggest that theories regarding self-focused motivations for altruism (e.g., self-enhancing reciprocity, reputation enhancement) alone are insufficient explanations for acts of real-world self-sacrifice.

Moral foundations, values, and judgments in extraordinary altruists

Donating a kidney to a stranger is a rare act of extraordinary altruism that appears to reflect a moral commitment to helping others. Yet little is known about patterns of moral cognition associated with extraordinary altruism. In this preregistered study, we compared the moral foundations, values, and patterns of utilitarian moral judgments in altruistic kidney donors (n = 61) and demographically matched controls (n = 58). Altruists expressed more concern only about the moral foundation of harm, but no other moral foundations. Consistent with this, altruists endorsed utilitarian concerns related to impartial beneficence, but not instrumental harm. Contrary to our predictions, we did not find group differences between altruists and controls in basic values. Extraordinary altruism generally reflected opposite patterns of moral cognition as those seen in individuals with psychopathy, a personality construct characterized by callousness and insensitivity to harm and suffering. Results link real-world, costly, impartial altruism primarily to moral cognitions related to alleviating harm and suffering in others rather than to basic values, fairness concerns, or strict utilitarian decision-making.

The bright and dark sides of egoism

Despite its negative reputation, egoism - the excessive concern for one's own welfare - can incite prosocial behavior. So far, however, egoism-based prosociality has received little attention. Here, we first provide an overview of the conditions under which egoism turns into a prosocial motive, review the benefits and limitations of egoism-based prosociality, and compare them with empathy-driven prosocial behavior. Second, we summarize studies investigating the neural processing of egoism-based prosocial decisions, studies investigating the neural processing of empathy-based prosocial decisions, and the small number of studies that compared the neural processing of prosocial decisions elicited by the different motives. We conclude that there is evidence for differential neural networks involved in egoism and empathy-based prosocial decisions. However, this evidence is not yet conclusive, because it is mainly based on the comparison of different experimental paradigms which may exaggerate or overshadow the effect of the different motivational states. Finally, we propose paradigms and research questions that should be tackled in future research that could help to specify how egoism can be used to enhance other prosocial behavior and motivation, and the how it could be tamed.

Neural defensive circuits underlie helping under threat in humans

Empathy for others’ distress has long been considered the driving force of helping. However, when deciding to help others in danger, one must consider not only their distress, but also the risk to oneself. Whereas the role of self-defense in helping has been overlooked in human research, studies in other animals indicate defensive responses are necessary for the protection of conspecifics. In this pre-registered study (N=49), we demonstrate that human defensive neural circuits are implicated in helping others under threat. Participants underwent fMRI scanning while deciding whether to help another participant avoid aversive electrical shocks, at the risk of also being shocked. We found that higher engagement of neural circuits that coordinate fast escape from self-directed danger (including the insula, PAG, and ACC) facilitated decisions to help others. Importantly, using representational similarity analysis, we found that the strength with which the amygdala and insula uniquely represented the threat to oneself (and not the other’s distress) predicted helping. Our findings indicate that in humans, as other mammals, defensive mechanisms play a greater role in helping behavior than previously understood.

Getting our Affect Together: Shared Representations as the Core of Empathy

Empathy is a construct that is notoriously difficult to define. Murphy and colleagues argue for leaning into the construct's inherent fuzziness and reverting to what they term a classical definition informed by the observations of philosophers and clinicians: as a dynamic, “unfolding process of imaginatively experiencing the subjective consciousness of another person, sensing, understanding, and structuring the world as if one were that person.” Although consistent with some historical conceptualizations, this definition risks incorporating so many processes it would make empathy difficult to operationalize or distinguish from any generally socially sensitive interaction. Defining empathy instead as the attempted representation, or simulation, of another's subjective internal experiences (whether sensory, affective, or cognitive) would increase its clarity and empirical utility.

Lesion Evidence for a Causal Role of the Insula in Aversion to Social Inequity

Humans resist unequal distributions of goods in their social interactions, even if it requires foregoing personal gains. Functional neuroimaging studies implicate the insula in this aversion to social inequity and in fairness-related decisions, but a causal contribution has not yet been established. We compared the responses of 30 patients with lesions to the insula on a multiple-trial version of the one-shot Ultimatum Game, a neuroeconomic social exchange paradigm where a sum of money is split between two players, to those of 30 matched patients with brain injuries sparing the insula. Insula lesion patients accepted offers of an unequal disadvantageous split significantly more often than comparison lesion patients. Computational modeling confirmed that this difference in choice behavior was due to decreased aversion to disadvantageous inequity following insula damage, rather than due to increased decision noise or non-consideration of inequity. Our results provide novel evidence that the insula is causally involved in aversion to inequity and in value-based choices in the context of social interactions.

Charity preferences and perceived impact moderate charitable giving and associated neural response

Charitable giving depends on individuals' abilities to make altruistic decisions. Previous studies suggest that altruism involves recruitment of neural resources in regions including social processing, reward/reinforcement learning, emotional response, and cognition. Despite evolutionary and social benefits to altruism, we know that humans do not always engage in altruistic behavior, like charitable giving. Understanding the underlying processes leading to decisions to donate is vital to improve prosocial community engagement. The present study examined how characteristics of the charitable giving opportunity influence an individual's decision to give and the neural engagement underlying these features. Twenty-nine participants subjectively rated ten charities on their value, effectiveness, and the subject's personal chance of donating. Participants then completed an fMRI task requiring them to decide to donate to certain charities given the probability of the donation helping, their personal preference for the charity, and whether the donation came at cost to themselves. There was a significant reduction in donating when the probability of helping was low versus high, and subjects were significantly less likely to donate to their lowest-rated charities. Further, probability of a donation being helpful and how much the subject favored a charity moderated PCC and left IFG engagement. Interestingly, reward neurocircuitry did not demonstrate similar sensitivity to these variations. These results may suggest individuals engage motivated reasoning to justify failure to donate, while donations are driven by emotion mentalizing that focuses on the welfare of others. This may provide valuable insight into how to engage individuals in altruistic giving.

A Feature-Based Network Analysis and fMRI Meta-Analysis Reveal Three Distinct Types of Prosocial Decisions

Tasks that measure correlates of prosocial decision-making share one common feature: agents can make choices that increase the welfare of a beneficiary. However, prosocial decisions vary widely as a function of other task features. The diverse ways that prosociality is defined and the heterogeneity of prosocial decisions have created challenges for interpreting findings across studies and identifying their neural correlates. To overcome these challenges, we aimed to organize the prosocial decision-making task space of neuroimaging studies. We conducted a systematic search for studies in which participants made decisions to increase the welfare of others during functional magnetic resonance imaging. We identified shared and distinct features of these tasks and employed an unsupervised graph-based approach to assess how various forms of prosocial decision-making are related in terms of their low-level components (e.g. task features like potential cost to the agent or potential for reciprocity). Analyses uncovered three clusters of prosocial decisions, which we labeled as cooperation, equity and altruism. This feature-based representation of the task structure was supported by results of a neuroimaging meta-analysis that each type of prosocial decisions recruited diverging neural systems. Results clarify some of the existing heterogeneity in how prosociality is conceptualized and generate insight for future research and task paradigm development.

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.

Help or flight? Increased threat imminence promotes defensive helping in humans

In humans and other mammals, defensive responses to danger vary with threat imminence, but it is unknown how those responses affect decisions to help conspecifics. Here, we manipulated threat imminence to investigate the impact of different defensive states on human helping behaviour. Ninety-eight healthy adult participants made trial-by-trial decisions about whether to help a co-participant avoid an aversive shock, at the risk of receiving a shock themselves. Helping decisions were prompted under imminent or distal threat, based on temporal distance to the moment of shock administration to the co-participant. Results showed that, regardless of how likely participants were to also receive a shock, they helped the co-participant more under imminent than distal threat. Reaction times and cardiac changes during the task supported the efficacy of the threat imminence manipulation in eliciting dissociable defensive states, with faster responses and increased heart rate during imminent compared to distal threats. Individual differences in empathic concern were specifically correlated with helping during imminent threats. These results suggest that defensive states driving active escape from immediate danger may also facilitate decisions to help others, potentially by engaging neurocognitive systems implicated in caregiving across mammals.

Activation in bed nucleus of the stria terminalis (BNST) corresponds to everyday helping

Everyday prosociality includes helping behaviors such as holding doors or giving directions that are spontaneous and low-cost and are performed frequently by the average person. Such behaviors promote a wide array of positive outcomes that include increased well-being, trust, and social capital, but the cognitive and neural mechanisms that support these behaviors are not yet well understood. Whereas costly altruistic responding to others' distress is associated with elevated reactivity in the amygdala, we hypothesized that everyday prosociality would be more closely associated with activation in the bed nucleus of the stria terminalis (BNST), a region of the extended amygdala known for its roles in maintaining vigilance for relevant socio-affective environmental cues and in supporting parental care. One previous study of the neural correlates of everyday prosociality highlighted a functional cluster identified as the septal area but which overlapped with established coordinates of BNST. We used an anatomical mask of BNST (Torrisi et al., 2015) to evaluate the association of BNST activation and daily helping in a sample of 25 adults recruited from the community as well as 23 adults who had engaged in acts of extraordinary altruism. Results found that activation in left BNST during an empathy task predicted everyday helping over a subsequent 14-day period in both samples. BNST activation most strongly predicted helping strangers and proactive helping. We conclude that beyond facilitating care for offspring, activation in BNST may provide a basis for the motivation to engage in a broad array of everyday helping behaviors.