This dissertation examines how agents process information and update their beliefs in two different contexts. In the first two chapters we consider dynamic decision problems under perfect information. In the last chapter we consider static, strategic interactions with common knowledge but imperfect information. To tackle our first set of questions we design an experiment analogous to the dynamic consumption problem with stochastic income that households solve in standard macroeconomic models. In the first chapter we show that our subjects condition on past actions in the absence of informational frictions or switching costs. We argue that subjects do so to economize on scarce cognitive resources and develop a model of inattentive reconsider...