Why Opt-Out Defaults Diminish Living Organ Donations

Opt-out defaults can motivate people towards more prosocial behavior and many countries have adopted opt-out defaults to increase deceased organ donation, energy conservation, or childhood vaccination. Prior studies show that opt-out defaults are powerful for increasing a specific cooperative behavior (e.g., deceased organ donation). However, little is known about how they may spillover to influence related cooperative behaviors (e.g., living organ donation) and how they may interact with mechanisms known to support human cooperation (e.g., inclusive fitness and reputation building). The present research addresses these gaps by investigating how an opt-out default policy for deceased organ donation influences the supply of living organs and how exposure to different default policies (opt-in or opt-out) alters perceptions of trust in others, inclusive fitness, and reputation building considerations. Across three studies, we show that the cooperative opt-out defaults for deceased organ donations have negative spillover-effects on living donations, which are larger for people with stronger pure altruistic tendencies. We show that this negative spillover effect is due to enhanced trust that organ supply approaches demand under opt-out. We further show that this interpretative change in organ supply leads to reduced living organ donations by (i) undermining the reputation-building effect of living organ donation and (ii) making people less willing to donate a living organ to recipients low in genetic relatedness and emotional closeness. The study’s findings have important implications for policymakers who aim to increase human cooperation by setting cooperative defaults.

默认退出机制（opt-out default）可激励人们做出更多亲社会行为，诸多国家已采用该机制以提高已故器官捐献（deceased organ donation）、节能或儿童疫苗接种的参与率。已有研究表明，默认退出机制对提升特定合作行为效果显著，例如已故器官捐献。然而，学界对其如何溢出影响相关合作行为（如活体器官捐献（living organ donation）），以及其与已知的人类合作支撑机制（如广义适合度（inclusive fitness）与声誉构建（reputation building））间的交互作用仍知之甚少。本研究旨在填补这一研究空白，探究已故器官捐献的默认退出政策如何影响活体器官供给，以及接触不同默认政策（默认加入（opt-in）与默认退出（opt-out））后，人们对他人的信任度、广义适合度感知与声誉构建考量会发生何种变化。三项研究结果显示，已故器官捐献的合作型默认退出机制会对活体器官捐献产生负向溢出效应，且该效应在具有更强纯粹利他倾向（pure altruistic tendency）的人群中更为显著。进一步分析表明，这一负向溢出效应源于默认退出机制下，人们对器官供给需求的信任度提升。此外，本研究还发现，这种对器官供给的认知转变会通过两种途径减少活体器官捐献：一是削弱活体器官捐献的声誉构建效应，二是降低人们向遗传亲缘关系与情感亲密度较低的受捐者捐献活体器官的意愿。本研究的发现对旨在通过设定合作型默认机制提升人类合作水平的政策制定者具有重要参考价值。