Moral contagion: Devaluation effect of immorality on hypothetical judgments of economic value.

Moral contagion is a phenomenon in which individuals or objects take on the moral essence of the people who are associated with them. Previous studies have found that individuals value objects associated with moral and likable people more than those associated with immoral and dislikable people. However, the neural mechanisms underlying this "moral contagion effect" have not yet been explored. In the present study, we combined a novel "Second-hand Goods Pricing" paradigm with functional magnetic resonance imaging to (a) confirm the existence of the moral contagion effect on the hypothetical economic valuation of objects and (b) determine the neural substrates underlying it. Participants were shown second-hand goods, information regarding the moral valence of the previous owner, and an initial price assigned to the object by computer. The participants were then asked to adjust the initial price to one they deemed most reasonable. Behaviorally, we found a significant devaluation effect for immoral owners and a weaker reverse effect for moral owners. Imaging data showed that the devaluation effect was primarily driven by neural responses in the dorsal striatum (mainly the caudate nucleus) that were triggered by high initial prices assigned to the "contaminated" objects. Dynamic causal modeling revealed that the high initial price assigned to "contaminated" objects led to increased effective connectivity from the caudate nucleus to the ventromedial prefrontal cortex-the brain area that integrates values during decision making.