We investigate the role that self-control problems — modeled as time-inconsistent, present-biased preferences —and a person’s awareness of those problems might play in leading people to develop and maintain harmful addictions. Present-biased preferences create a tendency to over-consume addictive products, and awareness of future self-control problems can mitigate or exacerbate this over-consumption, depending on the environment. Our central concern is the welfare consequences of this over-consumption. Our analysis suggests that for realistic environments self-control problems are a plausible source of severely harmful addictions only in conjunction with some unawareness of future self-control problems.

Previous papers on time-inconsistent procrastination assume projects are completed once begun. We develop a model in which a person chooses whether and when to complete each stage of a long-term project. In addition to procrastination in starting a project, a naive person might undertake costly effort to begin a project but then never complete it. When the costs of completing different stages are more unequal, procrastination is more likely, and it is when later stages are more costly that people start but don't finish projects. Moreover, if the structure of costs over the course of a project is endogenous, people are prone to choose cost structures that lead them to start but not finish projects. We also consider several extensions of the model that further illustrate how people may incur costs on projects they never complete.

Recent models of procrastination due to self-control problems assume that a procrastinator considers just one option and is unaware of her self-control problems. We develop a model where a person chooses from a menu of options and is partially aware of her self-control problems. This menu model replicates earlier results and generates new ones. A person might forego completing an attractive option because she plans to complete a more attractive but never-to-be-completed option. Hence, providing a non-procrastinator additional options can induce procrastination, and a person may procrastinate worse pursuing important goals than unimportant ones.

This paper explores some of the ways that economists can incorporate insights from recent research combining psychology and economics to help understand risky behavior by adolescents.

Previous papers on time-inconsistent procrastination assume projects are completed once begun. We develop a model in which a person chooses whether and when to complete each stage of a long-term project. In addition to procrastination in starting a project, a naive person might undertake costly effort to begin a project but then never complete it. When the costs of completing different stages are more unequal, procrastination is more likely, and it is when later stages are more costly that people start but don't finish projects. Moreover, if the structure of costs over the course of a project is endogenous, people are prone to choose cost structures that lead them to start but not finish projects. We also consider several extensions of the model that further illustrate how people may incur costs on projects they never complete.

People underappreciate how their own behavior and exogenous factors affect their future utility, and thus exaggerate the degree to which their future preferences resemble their current preferences. We present evidence which demonstrates the prevalence of such projection bias, and develop a formal model that draws out both descriptive and welfare implications of the bias. The model helps interpret established behavioral anomalies such as the endowment effect, and helps to explain commonly observed suboptimal patterns of behavior such as addiction and excessive pursuit of a high material standard of living. The model also suggests potentially welfare-improving policies, such as mandatory "cooling-off periods" for certain types of consumer decisions.