A reward prediction error for charitable donations reveals outcome orientation of donators

Longitudinal neural and behavioral trajectories of charity contributions across adolescence

This study examined the development of prosocial charity donations and neural activity in the ventral striatum when gaining rewards for self and for charity. Participants 10-22 years (95% European heritage) participated in three annual behavioral-fMRI waves (T1: n = 160, T2: n = 167, T3: n = 175). Behaviorally, donations to charity as measured with an economic Dictator Game increased with age. Perspective taking also increased with age. In contrast, self-gain and charity-gain enjoyment decreased with age. Ventral striatum activity was higher for rewards for self than for charity, but this difference decreased during adolescence. Latent growth curve models revealed that higher donations were associated with a smaller difference between ventral striatum activation for self and charity. These findings show longitudinal brain-donations associations in adolescence.

Voluntary or reluctant? Social influence in charitable giving: an ERP study

Social information has substantial influences on prosocial behavior. In this study, we performed an event-related potential (ERP) experiment to examine the effect of social influence on giving. The participants were allowed to form an initial decision on how much money to donate to a charity provided the program's average donation amount and to make a second donation decision. Social influence varied in different directions (upward, downward and equal) by altering the relative donation amount between the average donation amount and the participants' first donation amount. The behavioral results showed that participants increased their donation amount in the upward condition and decreased it in the downward condition. The ERP results revealed that upward social information evoked larger feedback-related negativity (FRN) amplitudes and smaller P3 amplitudes than in the downward and equal conditions. Furthermore, the pressure ratings, rather than the happiness ratings, were associated with the FRN patterns across the three conditions. We argue that people in social situations are more likely to increase their donations owing to pressure than voluntary altruism. Our study provides the first ERP evidence that different directions of social information evoke different neural responses in time course processing.

Neural sensitivity to helping outcome predicts helping decision in real life

Prosocial helping behavior is a highly valued social practice across societies, but the willingness to help others varies among persons. In our opinion, that willingness should be associated with the sensitivity to helping outcome at the individual level - that is, increasing as a function of positive outcome sensitivity but decreasing as a function of negative outcome sensitivity. To examine this possibility, we asked participants to make helping decisions in a series of hypothetical scenarios, which provided outcome feedback (positive/negative) of those decisions. Event-related potential (ERP) response to helping outcome was recorded, such that the feedback-related negativity (FRN) and P300 were supposed to reflect the sensitivity to negative outcome and positive outcome, respectively. After the formal task, participants were asked if they would like to donate money to a charity. Consistent with our hypothesis, we found that compared to those who were not willing to donate, the participants who donated money (22 of 41 individuals) showed a smaller FRN but a larger P300. Among these participants, the amount of donation was negatively correlated with FRN response to negative outcome, but positively correlated with P300 response to positive outcome. These findings support the importance of helping outcome sensitivity to prosocial behavior.

A biomarker of maternal vicarious reward processing and its association with parenting behavior

Parenting styles play a critical role in child well-being, yet the neural bases of parenting behaviors remain nebulous. Understanding the neural processes associated with parenting styles can both clarify etiological mechanisms underlying parenting behaviors and point us toward new targets for intervention. A novel electrocortical biomarker called the observational reward positivity (oRewP) that occurs in response to observing another receive a reward has been linked to self-reported authoritarian parenting behavior. The current study sought to replicate associations between the oRewP and self-reported and observationally-coded parenting in a sample of mothers selected to be at elevated risk for problematic parenting. Self-reported authoritarian parenting was associated with observationally-coded problematic discipline, while no other self-reported parenting scales were associated with observationally-coded scores. We replicated the previously reported association between a blunted oRewP and increased self-reported authoritarian parenting. We additionally found that an attenuated oRewP was associated with greater permissive parenting, and that only the relationship with permissive parenting was conserved after adjusting for other parenting styles and other relevant covariates. We did not find significant associations between the oRewP and observationally-coded parenting. The current findings suggest that the neural process indexed by the oRewP are relevant to parenting behavior. Further research is needed to better understand the discrepancy between self-reported and observed parenting.

Multivariate pattern analysis of electroencephalography data reveals information predictive of charitable giving

Charitable donations are an altruistic behavior whereby individuals donate money or other resources to benefit others while the recipient is normally absent from the context. Several psychological factors have been shown to influence charitable donations, including a cost-benefit analysis, the motivation to engage in altruistic behavior, and the perceived psychological benefits of donation. Recent work has identified the ventral medial prefrontal cortex (MPFC) for assigning value to options in social decision making tasks, with other regions involved in empathy and emotion contributing input to the value computation (e.g. Hare et al., 2010; Hutcherson et al., 2015; Tusche et al., 2016). Most impressively, multivariate pattern analysis (MVPA) has been applied to fMRI data to predict donation behavior on a trial-by-trial basis from ventral MPFC activity (Hare et al., 2010) while identifying the contribution of emotional processing in other regions to the value computation (e.g. Tusche et al., 2016). MVPA of EEG data may be able to provide further insight into the timing and scalp topography of neural activity related to both value computation and emotional effects on donation behavior. We examined the effect of incidental emotional states and the perceived urgency of the charitable cause on donation behavior using support vector regression on EEG data to predict donation amount on a trial by trial basis. We used positive, negative, and neutral pictures to induce incidental emotional states in participants before they made donation decisions concerning two types of charities. One category of charity was oriented toward saving people from current suffering, and the other was to prevent future suffering. Behaviorally, subjects donated more money in a negative emotional state relative to other emotional states, and more money to alleviate current over future suffering. The data-driven multivariate pattern analysis revealed that the electrophysiological activity elicited by both emotion-priming pictures and charity cues could predict the variation in donation magnitude on a trial-by-trial basis.

Neurocomputational models of altruistic decision-making and social motives: Advances, pitfalls, and future directions

This article discusses insights from computational models and social neuroscience into motivations, precursors, and mechanisms of altruistic decision-making and other-regard. We introduce theoretical and methodological tools for researchers who wish to adopt a multilevel, computational approach to study behaviors that promote others' welfare. Using examples from recent studies, we outline multiple mental and neural processes relevant to altruism. To this end, we integrate evidence from neuroimaging, psychology, economics, and formalized mathematical models. We introduce basic mechanisms-pertinent to a broad range of value-based decisions-and social emotions and cognitions commonly recruited when our decisions involve other people. Regarding the latter, we discuss how decomposing distinct facets of social processes can advance altruistic models and the development of novel, targeted interventions. We propose that an accelerated synthesis of computational approaches and social neuroscience represents a critical step towards a more comprehensive understanding of altruistic decision-making. We discuss the utility of this approach to study lifespan differences in social preference in late adulthood, a crucial future direction in aging global populations. Finally, we review potential pitfalls and recommendations for researchers interested in applying a computational approach to their research. This article is categorized under: Economics > Interactive Decision-Making Psychology > Emotion and Motivation Neuroscience > Cognition Economics > Individual Decision-Making.

Ageing is associated with disrupted reinforcement learning whilst learning to help others is preserved

Reinforcement learning is a fundamental mechanism displayed by many species. However, adaptive behaviour depends not only on learning about actions and outcomes that affect ourselves, but also those that affect others. Using computational reinforcement learning models, we tested whether young (age 18-36) and older (age 60-80, total n = 152) adults learn to gain rewards for themselves, another person (prosocial), or neither individual (control). Detailed model comparison showed that a model with separate learning rates for each recipient best explained behaviour. Young adults learned faster when their actions benefitted themselves, compared to others. Compared to young adults, older adults showed reduced self-relevant learning rates but preserved prosocial learning. Moreover, levels of subclinical self-reported psychopathic traits (including lack of concern for others) were lower in older adults and the core affective-interpersonal component of this measure negatively correlated with prosocial learning. These findings suggest learning to benefit others is preserved across the lifespan with implications for reinforcement learning and theories of healthy ageing.

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.

Neural reward-related reactions to monetary gains for self and charity

The aim of the present study was to examine the neural signatures of gaining money for self and charity. Young adults (N = 31, 21-24 years of age) underwent fMRI scanning while they performed a task in which they could earn money for themselves and for a self-chosen charity by selecting one of two options with unknown outcomes. The results showed elevated activity in the ventral striatum when gaining for the self only and for self and charity, but not when gaining for charity only. However, increased ventral striatal activity when gaining for charity only was correlated with participants' self-reported empathic concern and enjoyment when winning for charity. Empathic concern was also related to donating a larger proportion of earnings to charity after the MRI session. In short, these results reveal robust ventral striatal activity when gaining for oneself, but empathy-dependent individual differences in ventral striatal activity when gaining for charity.

Neural reward related-reactions to monetar gains for self and charity are associated with donating behavior in adolescence

The aim of the current study was to examine neural signatures of gaining money for self and charity in adolescence. Participants (N = 160, aged 11–21) underwent functional magnetic resonance imaging-scanning while performing a zero-sum vicarious reward task in which they could either earn money for themselves at the expense of charity, for a self-chosen charity at the expense of themselves, or for both parties. Afterwards, they could donate money to charity, which we used as a behavioral index of giving. Gaining for self and for both parties resulted in activity in the ventral striatum (specifically in the NAcc), but not gaining for charity. Interestingly, striatal activity when gaining for charity was positively related to individual differences in donation behavior and perspective taking. Dorsal anterior cingulate cortex, insula and precentral gyrus were active when gaining only for self, and temporal-parietal junction when gaining only for charity, relative to gaining for both parties (i.e. under equity deviation). Taken together, these findings show that striatal activity during vicarious gaining for charity depends on levels of perspective taking and predicts future acts of giving to charity. These findings provide insight in the individual differences in the subjective value of prosocial outcomes.

Neural Mechanisms of Vicarious Reward Processing in Adults with Autism Spectrum Disorder

Previous studies examining the neural substrates of reward processing in ASD have explored responses to rewards for oneself but not rewards earned for others (i.e., vicarious reward). This omission is notable given that vicarious reward processing is a critical component of creating and maintaining social relationships. The current study examined the neural mechanisms of vicarious reward processing in 15 adults with ASD and 15 age- and gender-matched typically developing controls. Individuals with ASD demonstrated attenuated activation of reward-related regions during vicarious reward processing. Altered connectivity was also observed in individuals with ASD during reward receipt. These findings of altered neural sensitivity to vicarious reward processing may represent a mechanism that hinders the development of social abilities in ASD.

Computing Social Value Conversion in the Human Brain

Social signals play powerful roles in shaping self-oriented reward valuation and decision making. These signals activate social and valuation/decision areas, but the core computation for their integration into the self-oriented decision machinery remains unclear. Here, we study how a fundamental social signal, social value (others' reward value), is converted into self-oriented decision making in the human brain. Using behavioral analysis, modeling, and neuroimaging, we show three-stage processing of social value conversion from the offer to the effective value and then to the final decision value. First, a value of others' bonus on offer, called offered value, was encoded uniquely in the right temporoparietal junction (rTPJ) and also in the left dorsolateral prefrontal cortex (ldlPFC), which is commonly activated by offered self-bonus value. The effective value, an intermediate value representing the effective influence of the offer on the decision, was represented in the right anterior insula (rAI), and the final decision value was encoded in the medial prefrontal cortex (mPFC). Second, using psychophysiological interaction and dynamic causal modeling analyses, we demonstrated three-stage feedforward processing from the rTPJ and ldPFC to the rAI and then from rAI to the mPFC. Further, we showed that these characteristics of social conversion underlie distinct sociobehavioral phenotypes. We demonstrate that the variability in the conversion underlies the difference between prosocial and selfish subjects, as seen from the differential strength of the rAI and ldlPFC coupling to the mPFC responses, respectively. Together, these findings identified fundamental neural computation processes for social value conversion underlying complex social decision making behaviors.SIGNIFICANCE STATEMENT In daily life, we make decisions based on self-interest, but also in consideration for others' status. These social influences modulate valuation and decision signals in the brain, suggesting a fundamental process called value conversion that translates social information into self-referenced decisions. However, little is known about the conversion process and its underlying brain mechanisms. We investigated value conversion using human fMRI with computational modeling and found three essential stages in a progressive brain circuit from social to empathic and decision areas. Interestingly, the brain mechanism of conversion differed between prosocial and individualistic subjects. These findings reveal how the brain processes and merges social information into the elemental flow of self-interested decision making.

Reward circuitry activation reflects social preferences in the face of cognitive effort

Research at the intersection of social neuroscience and cognitive effort is an interesting new area for exploration. There is great potential to broaden our understanding of how social context and cognitive effort processes, currently addressed in disparate literatures, interact with one another. In this paper, we briefly review the literature on cognitive effort, focusing on effort-linked valuation and the gap in the literature regarding cognitive effort in the social domain. Next, we present a study designed to explore valuation processes linked to cognitive effort within the social context of an inequality manipulation. More specifically, we created monetary inequality among the participant (SELF, endowed with $50) and two confederates: one also endowed with $50 (OTHER HIGH) and another with only $5 (OTHER LOW). We then scanned participants using fMRI as they attempted to earn bonus payments for themselves and others through a cognitively effortful feedback-based learning task. Positive feedback produced significantly greater activation than negative feedback in key valuation regions, the ventral striatum (VS) and ventromedial prefrontal cortex (vmPFC), both when participants were performing the task on their own behalf and when earning rewards for others. While reward-related activity in the VS was exaggerated for SELF compared to OTHER HIGH for both positive and negative feedback, activity in the vmPFC did not distinguish between recipients in the group-level results. Furthermore, participants naturally fell into two groups: those most engaged when playing for themselves and those who reported engagement for others. While Self-Engaged participants showed differences between the SELF and both OTHER conditions in the VS and vmPFC, Other-Engaged participants only showed an attenuated response to negative feedback for OTHER HIGH compared to SELF in the VS and no differences between recipient conditions in the vmPFC. Together, this work shows the importance of individual differences and the fragility of advantageous inequality aversion in the face of cognitive effort, highlighting the need to study cognitive effort in the social domain.

Friend versus foe: Neural correlates of prosocial decisions for liked and disliked peers

Although the majority of our social interactions are with people we know, few studies have investigated the neural correlates of sharing valuable resources with familiar others. Using an ecologically valid research paradigm, this functional magnetic resonance imaging study examined the neural correlates of prosocial and selfish behavior in interactions with real-life friends and disliked peers in young adults. Participants (N = 27) distributed coins between themselves and another person, where they could make selfish choices that maximized their own gains or prosocial choices that maximized outcomes of the other. Participants were more prosocial toward friends and more selfish toward disliked peers. Individual prosociality levels toward friends were associated negatively with supplementary motor area and anterior insula activity. Further preliminary analyses showed that prosocial decisions involving friends were associated with heightened activity in the bilateral posterior temporoparietal junction, and selfish decisions involving disliked peers were associated with heightened superior temporal sulcus activity, which are brain regions consistently shown to be involved in mentalizing and perspective taking in prior studies. Further, activation of the putamen was observed during prosocial choices involving friends and selfish choices involving disliked peers. These findings provide insights into the modulation of neural processes that underlie prosocial behavior as a function of a positive or negative relationship with the interaction partner.

Neuroanatomical correlates of donating behavior in middle childhood

The neurobiological correlates of prosocial behavior are largely unknown. We examined brain structure and functional connectivity correlates of donating to a charity, a specific, costly, form of prosocial behavior. In 163 children, donating was measured using a promotional clip for a charity including a call for donations. Children could decide privately whether and how much they wanted to donate from money they had received earlier. Whole brain structural MRI scans were obtained to study associations between cortical thickness and donating behavior. In addition, resting state functional MRI scans were obtained to study whole brain functional connectivity and to examine functional connectivity between regions identified using structural MRI. In the lateral orbitofrontal cortex/pars orbitalis and pre-/postcentral cortex, a thicker cortex was associated with higher donations. Functional connectivity with these regions was not associated with donating behavior. These results suggest that donating behavior is not only situationally driven, but is also related brain morphology. The absence of functional connectivity correlates might imply that the associations with cortical thickness are involved in different underlying mechanisms of donating.

The good lies: Altruistic goals modulate processing of deception in the anterior insula

When it comes to lies, the beneficiaries of one's dishonesty play an important role in the decision-making process. Altruistic lies that are made with the intention of benefiting others are a specific type of lies and very common in real life. While it has been shown that altruistic goals influence (dis)honest behaviors, the neural substrates of this effect is still unknown. To reveal how the brain integrates altruistic goals into (dis)honest decisions, this study used functional magnetic resonance imaging to examine the neural activity of participants in a real incentivized context while they were making (dis)honest decisions. We manipulated the beneficiaries of individuals' decisions (self vs. a charity) and whether the choices of higher payoffs involved deception or not. While finding that participants lied more often to benefit charities than for themselves, we observed that the altruistic goal of benefiting a charity, compared with the self-serving goal, reduced the activity in the anterior insula (AI) when lying to achieve higher payoffs. Furthermore, the degree of altruistic goal-induced reduction of AI activity was positively correlated with the degree of altruistic goal-induced reduction of honesty concerns. These results suggest that the AI serves as a neural hub in modulating the effect of altruistic goals on deception, which shed light on the underlying neural mechanism of altruistic lies. Hum Brain Mapp 38:3675-3690, 2017. © 2017 Wiley Periodicals, Inc.

To Know or Not to Know? Theta and Delta Reflect Complementary Information about an Advanced Cue before Feedback in Decision-Making

To investigate brain activity during the reinforcement learning process in social contexts is a topic of increasing research interest. Previous studies have mainly focused on using electroencephalograms (EEGs) for feedback evaluation in reinforcement learning tasks by measuring event-related potentials. Few studies have investigated the time–frequency (TF) profiles of a cue that manifested whether a following feedback is available or not after decision-making. Moreover, it remains unclear whether the TF profiles of the cue interact with different agents to whom the feedback related. In this study we used the TF approach to test EEG oscillations of the cue stimuli in three agents (‘Self’, ‘Other’, and ‘Computer’) conditions separately. The results showed that the increased central-posterior delta power was elicited by the feedback unavailable cues more so than with the feedback available cue within 200–350 ms after the onset of the cue, but only in the self-condition. Moreover, a frontal-central theta oscillation had enhanced power when following the feedback unavailable cue as opposed to the feedback available cue across three agencies. These findings demonstrated that the cue for knowing an outcome produced reward prediction error-like signals, which were mirrored by the delta and theta oscillations during decision-making. More importantly, the present study demonstrated that the theta and delta oscillations reflected separable components of the advanced cue processing before the feedback in decision-making.

Observational learning computations in neurons of the human anterior cingulate cortex

When learning from direct experience, neurons in the primate brain have been shown to encode a teaching signal used by algorithms in artificial intelligence: the reward prediction error (PE)—the difference between how rewarding an event is, and how rewarding it was expected to be. However, in humans and other species learning often takes place by observing other individuals. Here, we show that, when humans observe other players in a card game, neurons in their rostral anterior cingulate cortex (rACC) encode both the expected value of an observed choice, and the PE after the outcome was revealed. Notably, during the same task neurons recorded in the amygdala (AMY) and the rostromedial prefrontal cortex (rmPFC) do not exhibit this type of encoding. Our results suggest that humans learn by observing others, at least in part through the encoding of observational PEs in single neurons in the rACC.

Humans can learn alone or by watching others, strategies which may depend on similar or different neural networks. This study shows that people watching other players in a card game used computations in neurons of their rostral anterior cingulate cortex to learn through observation.

Goal-directed, habitual and Pavlovian prosocial behavior

Although prosocial behaviors have been widely studied across disciplines, the mechanisms underlying them are not fully understood. Evidence from psychology, biology and economics suggests that prosocial behaviors can be driven by a variety of seemingly opposing factors: altruism or egoism, intuition or deliberation, inborn instincts or learned dispositions, and utility derived from actions or their outcomes. Here we propose a framework inspired by research on reinforcement learning and decision making that links these processes and explains characteristics of prosocial behaviors in different contexts. More specifically, we suggest that prosocial behaviors inherit features of up to three decision-making systems employed to choose between self- and other- regarding acts: a goal-directed system that selects actions based on their predicted consequences, a habitual system that selects actions based on their reinforcement history, and a Pavlovian system that emits reflexive responses based on evolutionarily prescribed priors. This framework, initially described in the field of cognitive neuroscience and machine learning, provides insight into the potential neural circuits and computations shaping prosocial behaviors. Furthermore, it identifies specific conditions in which each of these three systems should dominate and promote other- or self- regarding behavior.

Goal or gold: overlapping reward processes in soccer players upon scoring and winning money

Social rewards are important incentives for human behavior. This is especially true in team sports such as the most popular one worldwide: soccer. We investigated reward processing upon scoring a soccer goal in a standard two-versus-one situation and in comparison to winning in a monetary incentive task. The results show a strong overlap in brain activity between the two conditions in established reward regions of the mesolimbic dopaminergic system, including the ventral striatum and ventromedial pre-frontal cortex. The three main components of reward-associated learning i.e. reward probability (RP), reward reception (RR) and reward prediction errors (RPE) showed highly similar activation in both con-texts, with only the RR and RPE components displaying overlapping reward activity. Passing and shooting behavior did not correlate with individual egoism scores, but we observe a positive correlation be-tween egoism and activity in the left middle frontal gyrus upon scoring after a pass versus a direct shot. Our findings suggest that rewards in the context of soccer and monetary incentives are based on similar neural processes.

Neuronal correlates of social decision making are influenced by social value orientation-an fMRI study

Our decisions often have consequences for other people. Hence, self-interest and other-regarding motives are traded off in many daily-life situations. Interindividually, people differ in their tendency to behave prosocial. These differences are captured by the concept of social value orientation (SVO), which assumes stable, trait-like tendencies to act selfish or prosocial. This study investigates group differences in prosocial decision making and addresses the question of whether prosocial individuals act intuitively and selfish individuals instead need to control egoistic impulses to behave prosocially. We address this question via the interpretation of neuronal and behavioral indicators. In the present fMRI-study participants were grouped into prosocial- and selfish participants. They made decisions in multiple modified Dictator-Games (DG) that addressed self- and other-regarding motives to a varying extent (self gain, non-costly social gain, mutual gain, costly social gain). Selfish participants reacted faster than prosocial participants in all conditions, except for decisions in the non-costly social condition, in which selfish participants displayed the longest decision times. In the total sample we found enhanced neural activity in the ventromedial prefrontal cortex (vmPFC) and dorsomedial prefrontal cortex (dmPFC/BA 9) during decisions that resulted in non-costly social benefits. These areas have been implicated in cognitive control processes and deliberative value integration. Decisively, these effects were stronger in the group of selfish individuals. We believe that selfish individuals require more explicit and deliberative processing during prosocial decisions. Our results are compatible with the assumption that prosocial decisions in prosocials are more intuitive, whereas they demand more active reflection in selfish individuals.

Cortical thickness and prosocial behavior in school-age children: A population-based MRI study

Prosocial behavior plays an important role in establishing and maintaining relationships with others and thus may have important developmental implications. This study examines the association between cortical thickness and prosocial behavior in a population-based sample of 6- to 9-year-old children. The present study was embedded within the Generation R Study. Magnetic resonance scans were acquired from 464 children whose parents had completed the prosocial scale of the Strengths and Difficulties Questionnaire. To study the association between cortical thickness and prosocial behavior, we performed whole-brain surface-based analyses. Prosocial behavior was related to a thicker cortex in a cluster that covers part of the left superior frontal and rostral middle frontal cortex (p < .001). Gender moderated the association between prosocial behavior and cortical thickness in a cluster including the right rostral middle frontal and superior frontal cortex (p < .001) as well as in a cluster covering the right superior parietal cortex, cuneus, and precuneus (p < .001). Our results suggest that prosocial behavior is associated with cortical thickness in regions related to theory of mind (superior frontal cortex, rostral middle frontal cortex cuneus, and precuneus) and inhibitory control (superior frontal and rostral middle frontal cortex).

The social brain and reward: social information processing in the human striatum

In the highly social life of humans, rewards that are sought and experienced are intertwined with social relationships and interactions between people. Just as we value nonsocial rewards such as food or money, we also value social outcomes (e.g., praise from a superior). We use social information to evaluate and form expectations of others and to make decisions involving others. Here we review research demonstrating how the neural circuitry of reward, particularly the striatum, is also involved in processing social information and making decisions in social situations. This research provides an understanding of the neural basis for social behavior from the perspective of how we evaluate social experiences and how our social interactions and decisions are motivated. We review research addressing the common neural systems underlying evaluation of social and nonsocial rewards. The human striatum, known to play a key role in reward processing, displays signals related to a broad spectrum of social functioning, including evaluating social rewards, making decisions influenced by social factors, learning about social others, cooperating, competing, and following social norms. WIREs Cogn Sci 2014, 5:61-73. doi: 10.1002/wcs.1266 Conflict of interest: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.

"An eye for an eye"? Neural correlates of retribution and forgiveness

Humans have evolved strong preferences for equity and fairness. Neuroimaging studies suggest that punishing unfairness is associated with the activation of a neural network comprising the anterior cingulate cortex, anterior insula, the ventral striatum, and the dorsolateral prefrontal cortex (DLPFC). Here, we report the neuronal correlates of retribution and “forgiveness” in a scenario, in which individuals first acted as a recipient in an Ultimatum Game, and subsequently assumed the position of a proposer in a Dictator Game played against the same opponents as in the Ultimatum Game. Most subjects responded in a tit-for-tat fashion, which was accompanied by activation of the ventral striatum, corroborating previous findings that punishing unfair behaviour has a rewarding connotation. Subjects distinguished between the human opponent and computer condition by activation of the ventromedial PFC in the human condition, indicative of mentalising. A substantial number of subjects did not retaliate. Neurally, this “forgiveness” behaviour was associated with the activation of the right (and to a lesser degree left) DLPFC, a region that serves as a cognitive control region and thus may be involved in inhibiting emotional responses against unfairness.

Interactions between the nucleus accumbens and auditory cortices predict music reward value

We used functional magnetic resonance imaging to investigate neural processes when music gains reward value the first time it is heard. The degree of activity in the mesolimbic striatal regions, especially the nucleus accumbens, during music listening was the best predictor of the amount listeners were willing to spend on previously unheard music in an auction paradigm. Importantly, the auditory cortices, amygdala, and ventromedial prefrontal regions showed increased activity during listening conditions requiring valuation, but did not predict reward value, which was instead predicted by increasing functional connectivity of these regions with the nucleus accumbens as the reward value increased. Thus, aesthetic rewards arise from the interaction between mesolimbic reward circuitry and cortical networks involved in perceptual analysis and valuation.

Neuronal reference frames for social decisions in primate frontal cortex

Social decisions are crucial for the success of individuals and the groups that they comprise. Group members respond vicariously to benefits obtained by others, and impairments in this capacity contribute to neuropsychiatric disorders such as autism and sociopathy. We examined the manner in which neurons in three frontal cortical areas encoded the outcomes of social decisions as monkeys performed a reward-allocation task. Neurons in the orbitofrontal cortex (OFC) predominantly encoded rewards that were delivered to oneself. Neurons in the anterior cingulate gyrus (ACCg) encoded reward allocations to the other monkey, to oneself or to both. Neurons in the anterior cingulate sulcus (ACCs) signaled reward allocations to the other monkey or to no one. In this network of received (OFC) and foregone (ACCs) reward signaling, ACCg emerged as an important nexus for the computation of shared experience and social reward. Individual and species-specific variations in social decision-making might result from the relative activation and influence of these areas.

Effort increases sensitivity to reward and loss magnitude in the human brain

It is ecologically adaptive that the amount of effort invested to achieve a reward increases the relevance of the resulting outcome. Here, we investigated the effect of effort on activity in reward and loss processing brain areas by using functional magnetic resonance imaging. In total, 28 subjects were endowed with monetary rewards of randomly varying magnitude after performing arithmetic calculations that were either difficult (high effort), easy (low effort) or already solved (no effort). Subsequently, a forced donation took place, where a varying part of the endowment was transferred to a charity organization, causing a loss for the subject. Results show that reward magnitude positively modulates activity in reward-processing brain areas (subgenual anterior cingulate cortex and nucleus accumbens) only in the high effort condition. Furthermore, anterior insular activity was positively modulated by loss magnitude only after high effort. The results strongly suggest an increasing relevance of outcomes with increasing previous effort.