Psychological research indicates that people have a cognitive bias that leads them to misinterpret new information as supporting previously held hypotheses. We show in a simple model that such confirmatory bias induces overconfidence: given any probabilistic assessment by an agent that one of two hypotheses is true, the appropriate beliefs would deem it less likely to be true. Indeed, the hypothesis that the agent believes in may be more likely to be wrong than right. We also show that the agent may come to believe with near certainty in a false hypothesis despite receiving an infinite amount of information.

We examine how principals should design incentives to induce time-inconsistent procrastinating agents to complete tasks efficiently. Delay is costly to the principal, but the agent faces stochastic costs of completing the task, and efficiency requires waiting when costs are high. If the principal knows the task-cost distribution, she can always achieve first-best efficiency. If the agent has private information, the principal can induce first-best efficiency for time-consistent agents, but often cannot for procrastinators. We show that second-best optimal incentives for procrastinators typically involve an increasing punishment for delay as time passes.