ABSTRACT
William James (1890) used the apt phrase "stream of consciousness to describe mental life. Had he chosen to describe an organism's overt behavior, he could just as aptly have used the phrase "stream of behavior," For behavior, like consciousness, is continuous, plastic, and reflective of the play of many simultaneously acting forces. Even the task of describing a "simple" organism, such as a rat, engaged in a "simple" task, as pressing a lever, requires that we consider a host of variables, including the response requirement, degree of deprivation, the consequences of lever pressing, and the consequences of engaging in competing activities. Moreover, these variables may interact in complex ways, and historical conditions may matter as well. Faced with this complexity, psychologists have developed techniques for fractionating performance into its component elements. For example, with the method of signal detection (Swets, Tanner, & Birdsall, 1961), it is possible to distinguish changes in perception from changes in motivation. In this chapter we describe a method that decomposes changes in behavior into two components: those that depend on reinforcement processes and those that are a function of motor performance. The method we use is based on the matching law equation (Herrnstein, 1970). Our purpose is to summarize the contribution that this method has made to some long-standing problems in behavioral pharmacology.
