Crowding-Theory introduces a new psychological effect into economics. Under identifiable conditions, a higher price or stricter regulation reduces the intrinsic motivation to perform a task. Crowding-Out is the only effect which systematically works in the opposite direction to the Relative Price Effect. Crowding-Out Theory is empirically applied to two issues in Switzerland: (1) The support for siting a nuclear waste repository strongly fell when the population was offered a compensation for hosting it. (2) The possibility of direct participation in politics via referenda tends to raise civic virtue, and (ceteris paribus) tax compliance (Crowding-In Effect).