Is there reason to believe that our brains have evolved to make efficient decisions so that the details of the internal process are irrelevant? I develop a model which illustrates a limitation of adaptive processes: improvements tend to come in the form of kludges. A kludge is a marginal...

We offer a theory of the sunk cost fallacy as an optimal response to limited memory. As new information arrives, a decision-maker may not remember all the reasons he began a project. The sunk cost gives additional information about future profits and informs subsequent decisions. The Concorde...