Despite the fact that people make decisions for others as often as they make decisions for themselves, little is known about how decisions for others are different from those made for the self. In two experiments, we investigated the effect of social distance (i.e., making decisions for oneself, a friend, or a stranger) on risk preferences in both gain and loss situations. We found that people were more risk averse in gain situations when they made decisions for themselves than for a stranger (Studies 1 and 2), but were equally risk averse for themselves and their friends (Study 2). However, people were more risk seeking in loss situations when they made decisions for themselves than for their friends as well as for a stranger, and were more risk seeking for their friends than for a stranger (Study 2). Furthermore, the effect of social distance on risk preferences was stronger in loss than in gain situations. Mediation analysis indicated that outcome-induced loss aversion was responsible for effects of social distance on risk preferences. These findings demonstrate that social distance influences risk preferences via perceived loss aversion, which sheds new light on self-other differences in decision making.

Individuals are consistently observed to be risk-averse over gains and risk-seeking over losses. This study examined whether increased social distance would change these behavioral patterns. To test our hypothesis, social distance was manipulated by asking the participants to make decisions either for themselves or for another person (Experiment 1), either for a known person or for an unknown person (Experiment 2), and either for a close friend or for a distant friend (Experiment 3). The results of Experiments 1 and 3 showed that increased social distance made people more risk-neutral, and such an effect was stronger in the gain domain than in the loss domain. However, the effect of social distance was not observed in Experiment 2. These findings suggest that risk preferences are influenced by the social distance between decision makers and beneficiaries.

Although self–other behavioral differences in decision making under risk have been observed in some contexts, little is known about the neural mechanisms underlying such differences. Using functional magnetic resonance imaging (fMRI) and the cups task, in which participants choose between risky and sure options for themselves and others in gain and loss situations, we found that people were more risk-taking when making decisions for themselves than for others in loss situations but were equally risk-averse in gain situations. Significantly stronger activations were observed in the dorsomedial prefrontal cortex (dmPFC) and anterior insula (AI) when making decisions for the self than for others in loss situations but not in gain situations. Furthermore, the activation in the dmPFC was stronger when people made sure choices for others than for themselves in gain situations but not when they made risky choices, and was both stronger when people made sure and risky choices for themselves than for others in loss situations. These findings suggest that gain–loss situation modulates self–other differences in decision making under risk, and people are highly likely to differentiate the self from others when making decisions in loss situations.