Desert and tangibility : decomposing house money effects in a charitable giving experiment

Several papers have documented that when subjects play with standard laboratory endowmentsʺ they make less self-interested choices then when they use money they have either earned through a laboratory task or brought from outside the lab. In the context of a charitable giving experiment we decompose common "house money" effects into two components: the tangibility of cash in hand relative to money (or ecu's) promised on a computer screen, and the desert of earned money relative to random windfall gains. While both components are found to be significant in non-parametric tests, the former effect, which has been neglected in previous studies, has a stronger effect on total donations. These results have clear implications for experimental design, and also suggest that the availability of less tangible payment methods may increase charitable donations.