Four pigeons on concurrent variable interval, variable ratio approximated the matching relationship with biases toward the variable interval when time spent responding was the measure of behavior and toward the variable ratio when frequency of pecking was the measure of behavior. The local rates of responding were consistently higher on the variable ratio, even when there was overall preference for the variable interval. Matching on concurrent variable interval, variable ratio was shown to be incompatible with maximization of total reinforcement, given the observed local rates of responding and rates of alternation between the schedules. Furthermore, it was shown that the subjects were losing reinforcements at a rate of about 60 per hour by matching rather than maximizing.Key words: concurrent VI VR, matching, maximization, reinforcement, pigeonsIn psychology, biology, and economics it is often assumed that behavioral adaptation entails optimization of some variable or set of variables, such as reinforcement rate, fitness, or wealth (Lea, 1978). In operant psychology one version of this view has motivated theories of concurrent schedule performance. It is, for example, argued that the matching relationship between choice proportions and reinforcement proportions is the result of some process that maximizes reinforcement rate (e.g., Mackintosh, 1974; Shimp, 1975). According to one version of maximization theory, the subject is said to choose between simultaneously available reinforcement schedules so as to produce the greatest reinforcement rate, summing across both schedules (e.g., Rachlin, Green, Kagel, & Battallio, 1976