But rational behavior is not a premise of economic theory, though it is often presented as such. The basic contention of theory is rather that competition will make it necessary for people to act rationally in order to maintain themselves. It is based not on the assumption that most or all of the participants in the market process are rational, but, on the contrary, on the assumption that it will in general be through competition that a few relatively more rational individuals will make it necessary for the rest to emulate them in order to prevail. Even the statement of the problem as one of utilizing knowledge dispersed among hundreds of thousands of individuals still over-simplifies its character. It is not merely a task of utilizing information about concrete facts which individuals already possess, but one of using their abilities of discovering such facts as will be relevant to their pruposes in particular situation.
Competition is as much a method for breeding certain types of mind as anything else.
I'm not sure what relation this story of adapting has to that of others, but there it is.