Stimulus generalization and the response-reinforcement contingency

Generalization gradients along a line-tilt continuum were obtained from groups of pigeons that had been trained to peck a key on different schedules of reinforcement. In Exp. I, gradients following training on a differential-reinforcement-of-low-rate (DRL) schedule proved to be much flatter than gradients following the usual 1-min variable interval (VI) training. In Exp. II, the value of the VI schedule itself was parametrically studied; Ss trained on long VI schedules (e.g., 4-min) produced much flatter gradients than Ss trained on short VI schedules (30-sec; 1-min). The results were interpreted mainly in terms of the relative control exerted by internal, proprioceptive cues on the different reinforcement schedules. Several implications of the results for other problems in the field of stimulus generalization are discussed

Interactions in multiple schedules: negative induction with squirrel monkeys

In Experiment I, lever pressing by squirrel monkeys was maintained under a sequence of variable-interval, multiple variable-interval variable-interval, and multiple variable-interval extinction schedules of food presentation. Negative induction (decreased responding in the unchanged component) occurred when one component of the multiple variable-interval variable-interval schedule was changed to extinction. Negative induction was transient over sessions; responding in the unchanged component usually recovered to a rate similar to that under the multiple variable-interval variable-interval schedule. Negative induction was not accompanied by consistent changes in the patterns of local responding within the unchanged component, and did not depend on whether component schedules were associated with localized (lever lights) or diffuse visual stimuli (houselights), or on whether the unchanged component was a 60- or 180-sec variable-interval schedule. In Experiment II, responding was maintained under a sequence of variable-interval and multiple variable-interval timeout schedules of food presentation. Negative induction occurred when responding declined gradually in the timeout component but not when responding declined abruptly. The nature of interactions in multiple schedules may depend on the species; negative induction was observed with squirrel monkeys under conditions similar to those that produce positive contrast with pigeons

Response allocation to concurrent fixed-ratio reinforcement schedules with work requirements by adults with mental retardation and typical preschool children.

The present experiments examined the effect of work requirements in combination with reinforcement schedule on the choice behavior of adults with mental retardation and preschool children. The work requirements of age-appropriate tasks (i.e., sorting silverware, jumping hurdles, tossing beanbags) were manipulated. Participants were presented with their choice of two response options for each trial that varied simultaneously on both work requirement and reinforcement schedule. Results showed that when responding to both choices occurred on the same reinforcement schedule, participants allocated most of their responses to the option with the easier work requirement. When the response option requiring less work was on a leaner reinforcement schedule, most participants shifted their choice to exert more work. There were individual differences across participants regarding their pattern of responding and when they switched from the lesser to the greater work requirement. Data showed that participants' responding was largely controlled by the reinforcement received for responding to each level of work. Various conceptualizations regarding the effects of work requirements on choice behavior are discussed