On the testable implications of collective choice theories

We analyze collective choices in game forms from a revealed preference viewpoint. We call the joint choice behavior of n agents Nash- (respectively, Pareto-) rationalizable if there exist n preferences over the conceivable joint actions such that the joint actions selected from each game form coincide with the Nash equilibria (respectively, the Pareto optima) of the corresponding game. In the two-agent case, we show that every deterministic joint behavior which is Nash-rationalizable is also Pareto-rationalizable. The converse if false. We further identify general necessary and sufficient conditions for Nash-rationalizability of an n-agent joint choice behavior. We also define and characterize partial versions of the Nash- and Pareto-rationalizability requirements. (C) 2000 Academic Press.