ADAPTING THE ENVIRONMENT INSTEAD OF ONESELF

This article examines some of the methods used by animals and humans t o adapt their environment Because there are limits on She number of di fferent tasks a creature can be designed to do well in, creatures with She capacity to redesign their environments have an adaptive advantag e over those who can adapt only passively to existing environmental st ructures. To clarify environmental redesign, I rely on the formal noti on of a task environment as a directed graph in which the nodes are st ates and the links are actions. One natural form of redesign is to cha nge the topology of this graph structure so as to increase the likelih ood of task success or to reduce its expected cost, measured in physic al terms. This may be done by eliminating initial states, hence elimin ating choice points; by changing the action repertoire; by changing th e consequence function; and, lastly, by adding choice points. Another major method for adapting the environment is to change its cognitive c ongeniality. Such changes leave the state space formally intact but re duce the number and cost of mental operations needed for task success; they reliably increase the speed, accuracy, or robustness of performa nce. The last section of the article describes several of these episte mic or complementary actions found in human performance.