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Two groups of six rats received discrimination training with two auditory stimuli differing in intensity. During one stimulus, the schedule was variable interval; during the other, it was either variable … Two groups of six rats received discrimination training with two auditory stimuli differing in intensity. During one stimulus, the schedule was variable interval; during the other, it was either variable time or extinction. Both the variable time and extinction schedules resulted in differential rates of responding in the presence of the two stimuli. Extinction resulted in an earlier and more stable difference. Stimulus generalization gradients obtained along the noise-intensity dimension revealed peak shift with both procedures. In addition, a secondary peak to stimuli in between the two training stimuli occurred with the variable-time schedule.
Two groups of six rats received discrimination training with two auditory stimuli differing in intensity. During one stimulus, the schedule was variable interval; during the other, it was either variable … Two groups of six rats received discrimination training with two auditory stimuli differing in intensity. During one stimulus, the schedule was variable interval; during the other, it was either variable time or extinction. Both the variable time and extinction schedules resulted in differential rates of responding in the presence of the two stimuli. Extinction resulted in an earlier and more stable difference. Stimulus generalization gradients obtained along the noise-intensity dimension revealed peak shift with both procedures. In addition, a secondary peak to stimuli in between the two training stimuli occurred with the variable-time schedule.
Pigeons learned to discriminate between a white vertical line on a dark background (S+) and a monochromatic circle of light (S—) either with or without responses to S— (errors). Gradients … Pigeons learned to discriminate between a white vertical line on a dark background (S+) and a monochromatic circle of light (S—) either with or without responses to S— (errors). Gradients of inhibition, which were centered around S—, and which had greater than zero slopes, were obtained only from those subjects who learned to discriminate with errors. The results indicate that the occurrence of errors is a necessary condition for S— to function as an inhibitory stimulus. This finding is consistent with other performance differences in subjects who have learned to discriminate with and without errors.
Experiment I examined the role of a reduced rate of responding in the occurrence of behavioral contrast. Four rats and a pigeon were exposed to a two‐component multiple schedule in … Experiment I examined the role of a reduced rate of responding in the occurrence of behavioral contrast. Four rats and a pigeon were exposed to a two‐component multiple schedule in which one component was always a variable‐interval schedule. The second component was, at different times, either a variable‐time schedule in which food was delivered independently of responding, or extinction. Both extinction and the variable‐time schedule reduced the rate of responding in the second component. Behavioral contrast was observed, however, only when extinction was scheduled in the second component. Experiment II examined preference, as measured by time allocation in concurrent schedules for a variable‐interval schedule relative to a variable‐time schedule. Two rats displayed a lack of preference between the two schedules. The results of these experiments support a preference interpretation of behavioral contrast, which holds that behavioral contrast is the result of the introduction of a less‐preferred condition in one component of a multiple schedule.
The relationship between training conditions and stimulus generalization gradients was examined using tandem schedules of reinforcement. Schedules were selected so that frequency of reinforcement and rate of responding were varied … The relationship between training conditions and stimulus generalization gradients was examined using tandem schedules of reinforcement. Schedules were selected so that frequency of reinforcement and rate of responding were varied somewhat independently of each other. A peak‐shift in the generalization gradient was obtained when extinction had been associated with one of the stimuli. No comparable peak shift was obtained when there were equal response rates in the training stimuli even with dissimilar frequencies of reinforcement. The data imply that response rates at the end of training, rather than reinforcement frequency per se , determine the characteristics of the generalization gradient.