Interlocking schedules of reinforcement

Four male pigmented rats were exposed to a procedure designed to investigate the relation between several performance measures and a schedule continuum ranging from FR 36 to FI 2 through four intermediate interlocking schedules. On all schedules, each subject developed a stable performance that was generally break-and-run. Analysis of the cumulative records, post-S^R breaks, and running rates showed a continuum of performance related to the schedule continuum.     

Effects of reinforcement scheduling on simultaneous discrimination performance

Pigeons were trained on a discrete-trials, simultaneous discrimination procedure, with confusable stimuli such that asymptotic performance was about 85% correct. Trials were terminated if no response occurred within 2 sec of stimulus onset, so that probability of responding was free to vary. The schedule of reinforcement for correct responses was varied, with the following results: (1) there was no relation between frequency of reinforcement and accuracy of responding. (2) In extinction, the probability of responding fell to low levels, but accuracy remained roughly constant. (3) When reinforcement was available after a fixed number of trials or after a fixed number of correct responses, the probability of responding increased with successive trials after reinforcement, but accuracy was generally constant. (4) When every fifth correct response was reinforced, accuracy decreased immediately after reinforcement if the birds were required to respond on every trial.     

Behavioral momentum and the law of effect

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.     

Resistance to extinction in the steady state and in transition

Three experiments with pigeons explored the constancy of reinforcer omission during extinction conjectured by rate estimation theory. Experiment 1 arranged 3-component multiple variable-interval (VI) schedules with a mixture of food and extinction trials within each session. Reinforcers omitted to an extinction criterion increased with food-trial reinforcer rate. Experiment 2 arranged 3-component multiple VI schedules where components differed in rate or number of reinforcers. Resistance to extinction depended on the training reinforcer rate but not on the number of reinforcers omitted. Experiment 3 replicated the partial-reinforcement extinction effect within subjects in a discrete-trial procedure and found that more reinforcers were omitted in continuous- than in partial-reinforcement trials. A model of extinction based on behavioral momentum theory accounted for all the data.     

Analyzing Thorndike's Law Of Effect: The Question Of Stimulus-response Bonds

The stimulus—response bond postulated by Thorndike's (1911) law of effect is not required in a functional account of behavior in relation to its consequences. Moreover, the notion of a bond has been challenged by the findings of several experiments. Nevertheless, it remains viable in the light of reanalyses of those findings. Thorndike's suggestion that the strength of the bond depends on the magnitude of satisfaction is consistent with current research on resistance to change.     

Correction to: The structure of epistemic probabilities

Philosophical Studies - The original version of this article was published with an error in the final equation in this sentence on page 20 (section 3.6.1).     

The structure of epistemic probabilities

Philosophical Studies - The epistemic probability of A given B is the degree to which B evidentially supports A, or makes A plausible. This paper is a first step in answering the question of what...     

Variable-ratio versus variable-interval schedules: response rate, resistance to change, and preference

Two experiments asked whether resistance to change depended on variable-ratio as opposed to variable-interval contingencies of reinforcement and the different response rates they establish. In Experiment 1, pigeons were trained on multiple random-ratio random-interval schedules with equated reinforcer rates. Baseline response rates were disrupted by intercomponent food, extinction, and prefeeding. Resistance to change relative to baseline was greater in the interval component, and the difference was correlated with the extent to which baseline response rates were higher in the ratio component. In Experiment 2, pigeons were trained on multiple variable-ratio variable-interval schedules in one half of each session and on concurrent chains in the other half in which the terminal links corresponded to the multiple-schedule components. The schedules were varied over six conditions, including two with equated reinforcer rates. In concurrent chains, preference strongly overmatched the ratio of obtained reinforcer rates. In multiple schedules, relative resistance to response-independent food during intercomponent intervals, extinction, and intercomponent food plus extinction depended on the ratio of obtained reinforcer rates but was less sensitive than was preference. When reinforcer rates were similar, both preference and relative resistance were greater for the variable-interval schedule, and the differences were correlated with the extent to which baseline response rates were higher on the variable-ratio schedule, confirming the results of Experiment 1. These results demonstrate that resistance to change and preference depend in part on response rate as well as obtained reinforcer rate, and challenge the independence of resistance to change and preference with respect to response rate proposed by behavioral momentum theory.     

Effects of signaled and unsignaled alternative reinforcement on persistence and relapse in children and pigeons

Three experiments explored the impact of different reinforcer rates for alternative behavior (DRA) on the suppression and post‐DRA relapse of target behavior, and the persistence of alternative behavior. All experiments arranged baseline, intervention with extinction of target behavior concurrently with DRA, and post‐treatment tests of resurgence or reinstatement, in two‐ or three‐component multiple schedules. Experiment 1, with pigeons, arranged high or low baseline reinforcer rates; both rich and lean DRA schedules reduced target behavior to low levels. When DRA was discontinued, the magnitude of relapse depended on both baseline reinforcer rate and the rate of DRA. Experiment 2, with children exhibiting problem behaviors, arranged an intermediate baseline reinforcer rate and rich or lean signaled DRA. During treatment, both rich and lean DRA rapidly reduced problem behavior to low levels, but post‐treatment relapse was generally greater in the DRA‐rich than the DRA‐lean component. Experiment 3, with pigeons, repeated the low‐baseline condition of Experiment 1 with signaled DRA as in Experiment 2. Target behavior decreased to intermediate levels in both DRA‐rich and DRA‐lean components. Relapse, when it occurred, was directly related to DRA reinforcer rate as in Experiment 2. The post‐treatment persistence of alternative behavior was greater in the DRA‐rich component in Experiment 1, whereas it was the same or greater in the signaled‐DRA‐lean component in Experiments 2 and 3. Thus, infrequent signaled DRA may be optimal for effective clinical treatment.