TIME ALLOCATION IN CONCURRENT SCHEDULES: THE EFFECT OF SIGNALLED REINFORCEMENT 1

Herrnstein's (1970) hyperbolic matching equation describes the relationship between response rate and reinforcement rate. It has two estimated parameters, k and Re. According to one interpretation, k measures motor performance and Re measures the efficacy of the reinforcer maintaining responding relative to background sources of reinforcement. Experiment 1 tested this interpretation of the Re parameter by observing the effect of adding and removing an additional source of reinforcement to the context. Using a within-session procedure, estimates of Re were obtained from the responsereinforcer relation over a series of seven variable-interval schedules. A second, concurrently available variable-interval schedule of reinforcement was added and then removed from the context. Results showed that when the alternative was added to the context, the value of Re increased by 107 reinforcers per hour; this approximated the 91 reinforcers per hour obtained from this schedule. Experiment 2 investigated the effects of signaling background reinforcement on k and Re. The signal decreased Re, but did not have a systematic effect on k. In general, the results supported Herrnstein's interpretation that in settings with one experimenter-controlled reinforcement source, Re indexes the strength of the reinforcer maintaining responding relative to uncontrolled background sources of reinforcement.Key words: Herrnstein's hyperbola, matching law, background reinforcement, signaled reinforcement, lever press, rats Herrnstein (1970) formulated an elementary matching law equation for the case in which there is only a single measured source of reinforcement and a single measured response rate. The form of that equation is kRj BIRi+Re' (1) where B1 is response rate, R1 is reinforcement rate, and k and Re are fitted constants. The structural or curve-fitting definitions of the constants reveal the relationship between response rate and reinforcement rate implied by Equation 1. In the numerator, k is an estimate of the response-rate asymptote. For instance, as reinforcement rate increases, response rate approaches but does not exceed k. Thus, k is measured in the same units as the measured behavior (e.g., responses per minute). In the numerator, Re is equal to the rate of reinforcement that maintains a one-half asymp-The authors gratefully acknowledge the helpful comments of the reviewers and members of the Behavioral and Decision Analysis research seminar in the Department of Psychology at Harvard in the preparation of this manuscript. Correspondence regarding this article should be sent to Terry W. Belke, Department of Psychology, Biological Sciences Building, University of Alberta, Edmonton, Alberta T6G 2E9, Canada (E-mail: tbelke@cyber.psych.ualberta.ca).totic response rate. For example, when RI is equal to Re, response rate must be equal to k/2. Thus, Re is measured in the same units as the experimenter-controlled reinforcer (e.g., 0.10 mL sucrose servings per hour).On the basis of the matching law, Herrnstein (1970, 1974) provided em...

Section: Resultsmentioning

confidence: 72%

mentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Increasing and Signaling Background Reinforcement: Effect on the Foreground Response—reinforcer Relation

Belke

Heyman

1994

“…First, the synthetic concurrent procedure, from MacDonall's Experiment 1, required rats to make two presses on the changeover lever to change the stimuli and associated schedules, which resembles FR 2 for switching. Marcucella and Margolius (1978) and Pliskoff and Fetterman (1981) used concurrent VI procedures with main and switching keys and pigeons as subjects, and also required completing an FR changeover requirement to change the stimuli and associated schedules. To prevent responding during the FR changeover requirement, Marcucella and Margolius (1978) and Pliskoff and Fetterman (1981) stopped illuminating the main key until the FR was completed.…”

Section: Discussionmentioning

confidence: 99%

A Local Model of Concurrent Performance

MacDonall

1999

Concurrent procedures may be conceptualized as consisting of two pairs of schedules with only one pair operating at a time. One schedule of each pair arranges reinforcers for staying in the current alternative, and the other schedule arranges reinforcers for switching to the other alternative. These pairs alternate operation as the animal switches between choices. This analysis of the contingencies suggests that variables operating within an alternative produce behavior that conforms to the generalized matching law. Rats were exposed to one pair of stay and switch schedules in each condition, and the probabilities of reinforcement varied across conditions. Both run length and visit duration were power functions of the ratio of the probabilities of reinforcement for staying and switching. The local model, a model of performance on concurrent procedures, was derived from this power function. Performance on concurrent schedules was synthesized from the performances on the separate pairs. Both the generalized matching law and the local model fitted the synthesized concurrent performances. These results are consistent with the view that the contingencies in the alternative, the probability of stay and switch reinforcement, are responsible for performance consistent with the generalized matching law. These results are compatible with momentary maximizing and molar maximizing accounts of concurrent performance. Models of concurrent performance that posit comparisons among the alternatives are not easily applied to these results.Key words: concurrent schedules, probability of reinforcement, local models, stay schedules, switch schedules, lever press, rats Herrnstein's 1961 paper, showing that responses maintained by concurrent variableinterval (VI) VI schedules were apportioned as reinforcers were apportioned, occasioned experimental and theoretical work aimed at understanding this relationship. Currently, there are several theories that account for Herrnstein's result, which is now called matching. A significant advance was Baum's (1974) proposal of the generalized matching law,where B n is the number of responses or amount of time allocated to each alternative and R n is the number of reinforcers obtained at each alternative. The constant, a, is inter-I thank Larry DeCarlo for originally pointing out to me the importance of stay and switch schedules. I also thank Deidre Beneri, Christian Kolarz, Lisa Musorrafiti, Ben Ventura, and Michael Wong for assistance in collecting the data, and Jonathan Galente, our instrument maker, for building and maintaining the equipment. A Fordham University Faculty Research Grant supported, in part, this research. Portions of these data were presented at the 1998 meeting of the Society for the Quantitative Analyses of Behavior in Orlando, Florida.Address correspondence to the author at the Department of Psychology, Fordham University, Bronx, New York 10458 (E-mail: jmacdonall@murray.fordham.edu).preted as behavioral sensitivity to reinforcer allocation, and b is a bias towards one altern...

“…The study by Hershiser and Trapold does not provide the necessary data to assess whether this switching pattern of responding occurred, but others have reported such as pattern when studying mixed vs. multiple schedules (e.g., Dinsmoor, Browne, Lawrence, & Wasserman, 1971). In addition, Marcucella and Margolius (1978) appeal to a similar pattern to account for responding under concurrent VI VI schedules. Obviously further assessment of commitment and noncommitment procedures are needed as they relate to studies of preference.…”

Section: Discussionmentioning

confidence: 99%

Choosing Schedules of Signaled Appetitive Events Over Schedules of Unsignaled Ones

Badia

Ryan

Harsh

1981

Two experiments were completed allowing albino rats to choose between signaled and unsignaled reward conditions. These experiments examined the effects on preference of (1) response dependent versus response-independent reward and, (2) food pellets versus chocolate milk as the reward. All subjects preferred the signaled condition over the unsignaled condition, whether exposed to response-dependent, or to response-independent delivery of rewards. Preference was controlled most effectively by presenting both the signal itself and the correlated stimulus identifying the signaled condition. The signal presented alone (Extinction 3) controlled preference more effectively than did the stimulus correlated with the signaled condition (Extinction 2). The second experiment showed that the quality of the reinforcer (pellets and chocolate milk) did not affect preference for signaled reward since all subjects preferred the signaled condition at levels comparable to those observed in Experiment 1, with food pellets. These results, along with others, argue against species differences, response-dependency, and reinforcer quality as variables affecting the direction of preference.