Social anxiety undermines prosocial behaviors when required effort.

Social anxiety impairs interpersonal relationships, which rely heavily on prosocial behaviors essential for healthy social interactions. The influence of social anxiety on the dynamics of helping others, through stages of prosocial choice stimulus presentation and effort, is not well understood. This study combines two experiments that integrate effort-based decision-making tasks with electroencephalography to distinguish between the choice stimulus presentation and effort phases of prosocial behavior. We examined the prosocial intention and motivation of 36 individuals with high social anxiety (HSAs) and 36 with low social anxiety (LSAs). Participants exerted effort for personal or others' gain, as well as to avoid losses. Participants chose whether to exert effort and then completed a designated number of key presses within a time limit, either to accumulate rewards or to avoid losses for themselves or others. Findings reveal that social anxiety indeed diminishes prosocial intention and effort motivation for gain. Interestingly, once HSAs decide to engage in prosocial efforts for gain, evaluative anxiety helps them reduce prosocial apathy and redirect their attentional resources from threatening stimuli to the task at hand, bringing their level of prosocial effort on par with LSAs. Moreover, HSAs exhibit prosocial apathy toward both gains and losses, with more pronounced prosocial apathy observed in loss tasks. However, evaluative anxiety does not help reduce HSAs' prosocial apathy in loss tasks. Notably, when striving to avoid losses for others, even without evaluative anxiety, HSAs demonstrated prosocial behavior indistinguishable from that of LSAs, suggesting that the goal of avoiding loss promotes prosociality among HSAs. Overall, while social anxiety diminishes individual prosocial behavior, evaluative anxiety and sensitive action goals can mitigate its impact to some extent. These findings are critical for developing strategies to enhance psychological health and promote healthier social interactions.