Paris Saclay Seminar

Behavioural Spillovers Unpacked

Julien Picard (London School of Economics)

Feb 01, 2024, 12:15

RITM, Faculté Jean Monnet



Previous studies have shown that our past pro-social actions influence our future ones. So, which pro-social deeds inspire us to do more? Can nudges promoting these deeds crowd out this behavioural spillover? We study a social norm nudge promoting vegetarianism in an online experiment (n=2775). Our findings suggest that those who chose vegetarian options were more likely to donate to environmental charities. However, the social norm nudge crowds out donations among a population segment that initially responded positively to the nudge. Despite their appeal, social norm nudges may, therefore, be counterproductive. Our empirical strategy stems from a model describing how acting pro-socially affects individuals' willingness to do extra pro-social actions and how nudges can crowd out or crowd in this willingness. We identify these effects with an instrumental variable and explore heterogeneity with machine learning.


RITM, Faculté Jean Monnet
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