Strategic ignorance as a self-disciplining device

We analyse the decision of an agent with time-inconsistent preferences to c onsume a good that exerts an externality on future welfare. The extent of t he externality is initially unknown, but may be learned via a costless samp ling procedure. We show that when the agent cannot commit to future consump tion and learning decisions, incomplete learning may occur on a Markov perf ect equilibrium path of the resulting intra-personal game. Tn such a case, each agent's incarnation stops learning for some values of the posterior di stribution of beliefs and acts under self-restricted information. This cond uct is interpreted as strategic ignorance. All equilibria featuring this pr operty strictly Pareto dominate the complete learning equilibrium for ally posterior distribution of beliefs.