Altruism budgets or benevolence constraints? Pro-social behaviours across causes and domains

We examine the existence of altruism budgets (AB), which imply fixed monetary allocations to prosocial behaviours (PSB), and benevolence constraints (BC), which refer to wider limits to benevolent behaviour, giving rise to a substitution between PSB's across domains and causes, including volunteering and biological donations. Using longitudinal data from the Netherlands from 2003 to 2019, we exploit two exogenous shocks to charitable behaviour: the introduction of a tax incentive that increased donations to culture and the arts, and a large-scale emergency fundraising campaign targeting Syrian refugees and victims of Typhoon Haiyan. Our results provide no evidence of AB but robust evidence of BC. We find a robust and precisely estimated decline in volunteering of approximately 4.5 hours per month after the emergency aid campaign among donors. This pattern suggests that individuals substitute across different forms of prosocial behaviour, reallocating effort from non-monetary activities such as volunteering toward monetary contributions during periods of heightened charitable demand.