Altruism Begets Altruism1

We design an experiment to ask whether morally-motivated behavior, e.g., charitable giving, is history-dependent. Using a popular policy nudge, the default option, we exogenously vary altruism “now” and show that giving “now” causes a 66%- 200% increase in the probability of giving “later”; that is, altruism begets altruism. We further show that, consistent with psychological theory, the choice to behave altruistically “now”, rather than the nudge itself, is the crucial element in the causal relationship. These findings are consistent with a model of positive path-dependence, which we interpret as moral consistency