Incentives have surprisingly inconsistent effects when it comes to encouraging people to behave prosocially. Caroline, Eva, Bianca and Pamala explore this puzzle in their paper "Social Norms Offer Explanation for Inconsistent Effects of Incentives on Prosocial Behavior" (check it out HERE). If you don't have time to read the article here are 3 things that you should keep in mind:
They propose social norms as an explanation for the empirical puzzle of the inconsistent effects of incentives on prosocial behavior.
Blood donor incentives (in the form of financial payments or time off work) are associated with higher levels of blood donation if social norms are more positive.
The previously observed inconsistent effects of incentives may be explained by variability in social norms across societies and incentive types.