Happiest thought: Dynamics and behavior

Abstract

In the metaphor of behavioral momentum, the rate of a free operant in the presence of a discriminative stimulus is analogous to the velocity of a moving body, and resistance to change measures an aspect of behavior that is analogous to its inertial mass. An extension of the metaphor suggests that preference measures an analog to the gravitational mass of that body. The independent functions relating resistance to change and preference to the conditions of reinforcement may be construed as convergent measures of a single construct, analogous to physical mass, that represents the effects of a history of exposure to the signaled conditions of reinforcement and that unifies the traditionally separate notions of the strength of learning and the value of incentives. Research guided by the momentum metaphor encompasses the effects of reinforcement on response rate, resistance to change, and preference and has implications for clinical interventions, drug addiction, and self-control. In addition, its principles can be seen as a modern, quantitative version of Thorndike's (1911) Law of Effect, providing a new perspective on some of the challenges to his postulation of strengthening by reinforcement. Figure 2. Average response rates of pigeons in two components of a multiple VI VI schedule with 60 reinforcers per hour in one component and 20 per hour in the other, showing the effects of the rate of free food presentations during time-out periods between components. The upper panel shows response rates during the last hour of baseline training and the first hour of disruption by time-out food across four conditions. In the lower panel, these data are re-expressed as log ratios of response rates with free food to response rates in the immediately preceding baseline and plotted as functions of time-out food rate. Adapted from Nevin (1974, Experiment 1). Nevin & Grace: Law of Effect 78 BEHAVIORAL AND BRAIN SCIENCES (2000) 23:1Figure 3. Left panel displays average baseline response rates on the right key in three multiple-schedule components. In Component A, reinforcer rate for right-key responses was 15/hour, with 45 reinforcers per hour available concurrently for left-key responses. In Component B, reinforcer rate for right-key responses was 15/hour, and in Component C it was 60/hour; no reinforcers were given for leftkey responses in Components B and C. The right panel displays the slopes of functions characterizing resistance to satiation, resistance to prefeeding, and resistance to extinction in these three components. Standard errors are indicated by the error bars. Adapted from . D'Amato et al. (1958) and several subsequent researchers (see, e.g., vom Saal 1972) have shown that animals respond Nevin & Grace: Law of Effect Abstract: Nevin & Grace's behavioral-momentum model accommodates a large body of data. This commentary highlights some experimental findings that the model does not always predict. The model does not consistently predict resistance to change when response-independent food is delivered simultaneously wit...