A recent psychology study found that people sometimes reject overly generous offers from people because they imagine hidden ''phantom costs'' must be part of the transaction. Phantom costs occur when a person seems overly generous for no apparent reason. This study aims to explore whether people can imagine phantom costs when interacting with a robot. To this end, screen or physically embodied agents (human or robot) offered to people either a cookie or a cookie + \$2. Participants were then asked to make a choice whether they would accept or decline the offer. Results showed that people did perceive phantom costs in the offer + \$2 conditions when interacting with a human, but also with a robot, across both embodiment levels, leading to the characteristic behavioral effect that offering more money made people less likely to accept the offer. While people were more likely to accept offers from a robot than from a human, people more often accepted offers from humans when they were physically compared to screen embodied but were equally likely to accept the offer from a robot whether it was screen or physically embodied. This suggests that people can treat robots (and humans) as social agents with hidden intentions and knowledge, and that this influences their behavior toward them. This provides not only new insights on how people make decisions when interacting with a robot but also how robot embodiment impacts HRI research.

中文翻译：

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好得令人难以置信：人们拒绝机器人提供的免费礼物，因为它们推断出不良意图

最近的一项心理学研究发现，人们有时会拒绝别人过于慷慨的报价，因为他们认为隐藏的“幻影成本”一定是交易的一部分。当一个人无缘无故地显得过于慷慨时，就会出现幻影成本。这项研究旨在探讨人们在与机器人互动时是否可以想象虚拟成本。为此，屏幕或物理实体（人或机器人）向人们提供 cookie 或 cookie + \$2。然后参与者被要求做出选择是接受还是拒绝该提议。结果表明，在两个具体层面上，当与人类以及机器人互动时，人们确实会感知到要约中的幻影成本 + \$2 条件，从而导致特征性的行为效应，即提供更多的钱使人们不太可能接受要约。虽然人们比人类更有可能接受来自机器人的提议，但当与实体化的屏幕相比时，人们更经常接受来自人类的提议，但无论是屏幕还是实体化的机器人，人们同样有可能接受来自机器人的提议。这表明人们可以将机器人（和人类）视为具有隐藏意图和知识的社会主体，这会影响他们对机器人的行为。这不仅为人们在与机器人交互时如何做出决策提供了新的见解，而且还为机器人的具体化如何影响 HRI 研究提供了新的见解。