Matt and I recently discussed whether we thought the government should intervene to correct intra-personal externalities that arise from time inconsistency in peoples’ behaviour. We particularly talked about smoking: models of smoking which incorporate hyperbolic discounting predict that people will want to quit in the future but will never be able to quit when the time comes (and here I’ve horribly conflated two different causes of dynamic inconsistency in the interests of simplicity). I wasn’t able to persuade him that it is in the public interest to correct such externalities, but perhaps this paper(NBER) cited on MR provides a harsher example of the consequences of time inconsistency (and, yes, I know I’m horribly mangling together two different causes of dynamic inconsistency).
The authors find that
…women who are the victims of domestic violence often leave and return multiple times. … We present supporting evidence that women in violent relationships display time inconsistent preferences… We find that “no-drop” policies — which compel the prosecutor to continue with prosecution even if the victim expresses a desire to drop the charges — result in an increase in reporting. No-drop policies also result in a decrease in the number of men murdered by intimates suggesting that some women in violent relationships move away from an extreme type of commitment device when a less costly one is offered.
The problem here is that there is no device available to the women that allows them to commit to leaving the relationship and force their ‘future self’ not to return. A no-drop policy on the part of prosecutors gives them that precommitment power and prevents them from reneging on their desire to leave the abusive relationship. By restricting the womens’ future choice set the state can make them better off. I feel bad talking about domestic violence in such dry terminology, but I think this is a really good example of how economic theory can help understand important ‘real world’ problems. Policies such as taxation of smoking and no-drop prosecution of domestic violence are not examples of government interference in peoples’ lives: they are examples of the government helping people to help themselves.