Saito et al. (2019)

Saito, Y. (齋藤美松), Ueshima, A. (上島淳史), Tanida, S. (谷田林士), & Kameda, T. (亀田達也) (2019). 
How does social information affect charitable giving?: Empathic concern promotes support for underdog recipient
社会情報は寄付行動にどのような影響を与えるか: 共感的配慮が判官びいきを促進する
Social Neuroscience, 14, 751-764.
doi: 10.1080/17470919.2019.1599421

Charitable giving represents a unique cooperative characteristic of humans. In today’s environment with social media, our charitable decisions seem to be influenced by social information such as a project’s popularity. Here we report three experiments that examined people’s reactions to social information about a charitable endeavor and their psychophysiological underpinnings. Participants were first solicited to make donations to either the Africa or Syria project of UNICEF. Then participants were provided an opportunity to learn social information (i.e., how much each project had raised from previous participants) and change their decision if desired. Contrary to expectation, participants who learned that their initial preferences were consistent with the majority of previous participants’ choices exhibited a sizable tendency to switch to the less popular project in their final choices. This anti-conformity pattern was robust across the three experiments. Eye-tracking data (gaze bias and pupil dilation) indicated that these “Changers” were more physiologically aroused and formed more differential valuations between the two charity projects, compared to “Keepers” who retained their initial preferences after viewing the social information. These results suggest that social information about relative popularity may evoke empathic concern for the worse-off target, in line with the human tendency to avoid unequal distributions.