Do evolutionary processes minimize expected losses?

Evolution by variation and natural selection is often viewed as an optimiza tion process that favors those organisms which are best adapted to their en vironment. This leaves open the issue of how to measure adaptation and what criterion is implied for optimization. This problem has been framed and an alysed mathematically under the assumption that individuals compete to mini mize expected losses across a series of decisions (e.g. choice of behavior) , where each decision offers a stochastic payoff. But the fact that a parti cular analysis is tractable for a specified criterion does not imply the fi delity of that criterion. Computer simulations involving a version of the k -armed bandit problem can address the veracity of the hypothesis that indiv iduals are selected to minimize expected losses. The results offered here d o not support this hypothesis. (C) 2000 Academic Press.