Vickers Brian D, Seidler Rachael D, Stansfield R Brent, Weissman Daniel H, Preston Stephanie D
Department of Psychology, University of Michigan, Ann Arbor, MI, United States.
University of Michigan School of Kinesiology, Ann Arbor, MI, United States.
Front Psychiatry. 2023 Mar 10;14:1140986. doi: 10.3389/fpsyt.2023.1140986. eCollection 2023.
Why do people help strangers? Prior research suggests that empathy motivates bystanders to respond to victims in distress. However, this work has revealed relatively little about the role of the motor system in human altruism, even though altruism is thought to have originated as an active, physical response to close others in immediate need. We therefore investigated whether a motor preparatory response contributes to costly helping.
To accomplish this objective, we contrasted three charity conditions that were more versus less likely to elicit an active motor response, based on the Altruistic Response Model. These conditions described charities that (1) aided neonates versus adults, (2) aided victims requiring immediate versus preparatory support, and (3) provided heroic versus nurturant aid. We hypothesized that observing neonates in immediate need would elicit stronger brain activation in motor-preparatory regions.
Consistent with an evolutionary, caregiving-based theory of altruism, participants donated the most to charities that provided neonates with immediate, nurturant aid. Critically, this three-way donation interaction was associated with increased BOLD signal and gray matter volume in motor-preparatory regions, which we identified in an independent motor retrieval task.
These findings advance the field of altruism by shifting the spotlight from passive emotional states toward action processes that evolved to protect the most vulnerable members of our group.
为什么人们会帮助陌生人？先前的研究表明，同理心会促使旁观者对处于困境中的受害者做出反应。然而，尽管利他主义被认为起源于对有迫切需求的亲近他人的一种积极的身体反应，但这项研究相对较少揭示运动系统在人类利他主义中的作用。因此，我们研究了运动准备反应是否有助于代价高昂的帮助行为。
为实现这一目标，我们根据利他反应模型，对比了三种慈善情境，这些情境引发积极运动反应的可能性有高有低。这些情境描述的慈善机构分别是：(1) 救助新生儿与成年人；(2) 救助需要即时支持与准备阶段支持的受害者；(3) 提供英勇救助与养育性救助。我们假设，观察有迫切需求的新生儿会在运动准备区域引发更强的大脑激活。
与基于进化的、以照顾为基础的利他主义理论一致，参与者向为新生儿提供即时养育性救助的慈善机构捐赠最多。至关重要的是，这种三元捐赠交互作用与运动准备区域的血氧水平依赖（BOLD）信号增加和灰质体积增加有关，我们在一项独立的运动检索任务中确定了这些区域。
这些发现通过将焦点从被动情绪状态转向为保护我们群体中最脆弱成员而进化出的行动过程，推动了利他主义领域的发展。
