When being asked for help, people sometimes can only offer part of what is requested (i.e., partial help). The present research investigates whether helpers can accurately forecast how much help-seekers appreciate this understudied form of assistance. From multiple helping scenarios and a face-to-face interaction, we demonstrate an asymmetry in helpers’ and help-seeker’s appraisals of partial help: Helpers anticipated less appreciation for partial help than help-seekers felt in receiving it. This asymmetry arose from helpers’ greater valuation of helping outcomes over intentions to be helpful than help-seekers’. Accordingly, when helpers’ intentions were discounted, this asymmetry no longer persisted. Another account—helpers feel worse for breaking norms of helping than help-seekers—was not supported. We discuss several directions for future research on the psychology of partial prosocial behaviors.

当被请求帮助时，人们有时只能提供部分请求（即部分帮助））。目前的研究调查了帮助者是否能够准确预测求助者对这种未经研究的帮助形式的欣赏程度。从多个帮助场景和面对面的互动中，我们证明了帮助者和寻求帮助者对部分帮助的评价存在不对称性：帮助者对部分帮助的预期比寻求帮助者在接受部分帮助时所感受到的要少。这种不对称源于帮助者比寻求帮助者更重视帮助结果而不是帮助意图。因此，当帮助者的意图被打折扣时，这种不对称性不再存在。另一个说法——帮助者比寻求帮助的人对打破帮助规范的感觉更糟——没有得到支持。我们讨论了部分亲社会行为心理学未来研究的几个方向。