A two-stage model of the effects of prosocial effort on reward processing

Abstract: Prosocial behavior often requires people to incur personal costs to benefit others. Although many studies have focused on the benefits received by others, the effects of self-incurred costs on prosocial behavior remain underexplored. The few studies that have examined self-costs have mainly focused on the trade-off between effort costs and monetary rewards, overlooking the broader neural dynamics through which effort shapes the valuation of benefits to others. Recently, we demonstrated an effort paradox mechanism, whereby effort exerted for oneself both prospectively discounts and retrospectively enhances reward value. We hypothesize that this two-stage relationship between effort and reward may constitute a novel mechanism underlying prosocial behavior. To test this hypothesis, we will combine behavioral experiments with EEG and fMRI to examine the neural dynamics that arise when individuals exert cognitive effort to earn rewards for themselves versus for others. We will further determine whether these neural dynamics are domain-general or domain-specific across different forms of effort and benefit. These findings will clarify the cognitive and neural mechanisms by which prosocial effort shapes reward processing, thereby addressing a key gap in current theories and offering a new perspective on how self-incurred costs and others' benefits are balanced, and on how prosocial behavior can be promoted.