Behavioral momentum is a theory in quantitative analysis of behavior and is a behavioral metaphor based on physical momentum. It describes the general relation between resistance to change (persistence of behavior) and the rate of reinforcement obtained in a given situation.
B.F. Skinner (1938) proposed that all behavior is based on a fundamental unit of behavior called the discriminated operant. The discriminated operant, also known as the three-term contingency, has three components: an antecedent discriminative stimulus, a response, and a reinforcing or punishing consequence. The organism responds in the presence of the stimulus because past responses in the presence of that stimulus have produced reinforcement.
According to behavioral momentum theory, there are two separable factors that independently govern the rate with which a discriminated operant occurs and the persistence of that response in the face of disruptions such as punishment, extinction, or the differential reinforcement of alternative behaviors. (see Nevin & Grace, 2000, for a review). First, the positive contingency between the response and a reinforcing consequence controls response rates (i.e., a response–reinforcer relation) by shaping a particular pattern of responding. This is governed by the relative law of effect (i.e., the matching law; Herrnstein, 1970). Secondly, the Pavlovian relation between surrounding, or context, stimuli and the rate or magnitude (but not both) of reinforcement obtained in the context (i.e., a stimulus–reinforcer relation) governs the resistance of the behavior to operations such as extinction. Resistance to change is assessed by measuring responding during operations such as extinction or satiation that tend to disrupt the behavior and comparing these measurements to stable, pre-disruption response rates.
Resistance to disruption has been considered a better measure of response strength than a simple measure of response rate.(Nevin, 1974). This is because variations in reinforcement contingencies such as differential-reinforcement-of-high- or low-response-rate schedules can yield highly variable response rates even though overall reinforcement rates are equal. Thus it is questionable whether these differences in response rates indicate differences in the underlying strength of a response (see Morse, 1966, for a discussion).