How to commit (if you must): Commitment contracts and the dual-self model

This paper studies how dual-self (Fudenberg and Levine, 2006) decision-makers can use commitment technologies to combat temptation and implement long-run optimal actions. I consider three types of commitment technologies: carrot contracts (rewards for 'good' behavior financed by borrowing from future consumption), stick contracts (self imposed fines for 'bad' behavior) and binding commitment. I compare the welfare implications of these contracts and show that dual-self decision-makers strictly prefer to use carrots instead of either sticks or binding commitments. This is for several reasons: sticks are highly vulnerable to trembles (while carrots are not), sticks and binding commitments create a temptation to cancel them (while carrots do not), and finally carrots allow easy tradeoffs between commitment and flexibility (while sticks and binding commitments do not).