Your Artstor image groups were copied to Workspace. The Artstor website will be retired on Aug 1st. International Journal of the Commons Vol. 13, No. 1, 2019 The effects of social norms on motivatio..

Frey, Bruno S., and Felix Oberholzer-Gee. "The Cost of Price Incentives: An Empirical Analysis of Motivation Crowding-Out." American Economic Review 87, no. 4 (September 1997): 746–755.