We provide a full behavioral characterization of the standard Shannon model of rational inattention. The key axiom is "Invariance under Compression", which identifies this model as capturing an ideal form of attention-constrained choice. We introduce tractable generalizations that allow for many...

We develop a revealed preference test for optimal acquisition of costly information. The test encompasses models of rational inattention, sequential signal processing, and search. We provide limits on the extent to which attention costs can be recovered from choice data. We experimentally elicit...

With complete information, choice of one option over another conveys preference. Yet when search is incomplete, this is not necessarily the case. It may instead reflect unawareness that a superior alternative was available. To separate these phenomena, we consider non-standard data on the...