Résumé
We experimentally investigate the impact of income redistribution on voluntary contributions by groups of four subjects. We compare equalizing and unequalizing redistribution. Our data are consistent with the neutrality theorem: Redistribution does not affect the amount of voluntarily provided public good at the group level. However, at the individual level, subjects tend to underadjust with respect to the Nash prediction. We also observe an insignificant adjustment asymmetry between the poor and the rich: Subjects who become poorer adjust their contribution by a larger absolute amount than subjects who become richer. Finally, poor subjects tend to overcontribute significantly more than rich subjects.