Separating Operant and Pavlovian Processes through Discriminative-Stimulus Location

Abstract

Previous studies have shown responding to a key light will increase when a stimulus representing a reinforcement schedule is located on the response key. Moreover, previous research has shown behaviour during an environmental disruption to come under the control of visual but not auditory stimuli. The current study presented pigeons with a two-key procedure, alternating between two components. The right key of each component was associated with either a rich or lean schedule of reinforcement. The location of the stimuli representing each component was either located on the left key, or on both keys. Results showed no systematic effects of the stimulus location on baseline response rates. Responding to the right key during environmental disruption increased when the discriminative stimulus was located on that key. Moving the discriminative stimulus onto the right key did not change the relation between response and reinforcer – as reflected in no systematic change in response rates. Responding during disruption was consistent with Tomie’s (1995) model of increased responding when a discriminative stimuli is located on a response key. Furthermore, that this only occurred during disruption. Overall, changes in the response-reinforcer relation affected response rates, whereas changes to the stimulus-reinforcer relation (in the form of stimulus location) affected responses during disruption – consistent with the basic premises of behavioural momentum theory.