Evolution of communication with partial common interest

We experimentally investigate communication in sender-receiver games with i mperfect incentive alignment. We consider both a priori meaningless message s and messages with pre-established meanings. Under four canonical incentiv e conditions, we get communication outcomes. However, it is by no means a f ait accompli. We observe significant deterioration and recoding of a priori meanings, sucker behavior by receivers, and focal point and initial condit ion effects. A conservative partial common interest (PCI) condition general ly is a reliable, albeit coarse predictor of the form of communication. Equ ilibrium selection criteria sometimes improve on the PCI prediction but nei ther influentiality, ex ante efficiency, nor Farrell's neologism-proofness refinement is reliable across all games, and equilibria are not always obta ined. Considering comparative statics, equilibrium selection criteria are h elpful but imperfect predictors of how equilibrium frequencies respond to i ncentives, whereas the less ambitious PCI prediction is never rejected by t he data. (C) 2001 Academic Press.