If human behavior is to become more sustainable, people will have to be willing to sacrifice personal gains and benefits for the sake of sustainability. Decisions will have to involve making tradeoffs between what is good for the self and what is good for sustainability. In the present paper, we studied the psychology of such tradeoffs in the context of a carbon dioxide (CO₂) emission versus travel time tradeoff task. The experiment investigated how intrinsic motivational factors (environmental concern), extrinsic motivational information (a normative message) and extrinsic motivation-neutral information (anchors) influence these tradeoffs. The results revealed that extrinsic factors interact in their effects on tradeoffs such that participants were willing to travel for a longer time for the benefit of less CO₂ emissions when they were externally motivated by a normative message, but only when this motivational emphasis was combined with a high anchor. Furthermore, this interaction was particularly strong in participants with high environmental concern. We conclude that extrinsic and intrinsic motivational factors interact in their effect on making people willing to accept personal losses in exchange for sustainability gains and that these motivational factors may have to be combined with further extrinsic information to influence decisions.

如果要使人类行为更具可持续性，则人们必须愿意为了可持续性而牺牲个人收益和利益。决策必须涉及在对自己有利的事物与对可持续性有益的事物之间进行权衡。在本文中，我们研究了在二氧化碳（CO ₂）的排放量与行程时间的权衡任务。实验研究了内在的动机因素（环境问题），外在的动机信息（规范性信息）和外在的动机中性信息（锚）如何影响这些权衡。结果表明，外在因素在权衡取舍中相互作用，因此参与者愿意为了减少CO _2的排放而旅行更长的时间。当他们受到规范性信息的外部激励时，但只有当这种激励重点与较高的锚点结合在一起时，才会产生排放。此外，这种互动在对环境问题高度关注的参与者中尤其强烈。我们得出的结论是，外在动机和内在动机因素在使人们愿意接受个人损失以换取可持续性收益方面相互影响，并且这些动机因素可能必须与其他外在信息相结合才能影响决策。