Journal of the experimental analysis of behavior
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The contribution of the response-reinforcer dependency to the control of behavior was investigated. Pigeons were trained to key peck under a variable-interval schedule of reinforcement. ⋯ Response rates were related to the percentage of response-dependent reinforcement with lower response rates associated with smaller percentages of response-dependent reinforcement. The results suggest that the response-reinforcer relation exerts control over behavior in a manner similar to that exerted by other parameters of reinforcement.
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A change in the size of a fixed-ratio schedule involves a simultaneous change in number of responses, in time to complete the ratio (work time), and in the interval between successive reinforcements (interreinforcement interval). Previous studies have suggested the importance of work time and the interreinforcement interval in controlling the length of the post-reinforcement pause. The present study sought to determine whether number of responses is also a significant factor. ⋯ When the work times (Experiment I) or interreinforcement intervals (Experiment II) were equated for the two components, the pause before the fixed-ratio x was longer than the pause before the fixed-ratio 2 plus timeout. As fixed-ratio x size increased, the relative difference in the lengths of the two types of pauses also increased. Because the fixed-ratio x component contained a larger number of responses than the fixed-ratio 2 plus timeout component, the relatively longer pause preceding the fixed-ratio x indicates that number of responses played a significant role in determining the length of the post-reinforcement pause.
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Five pigeons were exposed to an unsignalled avoidance procedure where key pecks were maintained through shock postponement. Functions obtained showed an inverse relationship between rate of responding and length of the response-shock interval, while changes in the shock-shock interval had no systematic effect on response rates. The rate of shocks delivered generally decreased with increases in length of both response-shock and shock-shock intervals. Results show that key pecking in pigeons, maintained through an unsignalled avoidance procedure, was affected by changes in response-shock and shock-shock intervals in the same manner as other responses in pigeons and in rats.
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In several different experiments, pigeons were trained with one schedule or condition of food reinforcement for pecking in the presence of one key color, and a different schedule or condition in the presence of a second key color. After responding in both of these multiple schedule components stabilized, response-independent food was presented during dark-key periods between components, and the rates of pecking in both schedule components decreased. The decrease in responding relative to baseline depended on the frequency, magnitude, delay, or response-rate contingencies of reinforcement prevailing in that component. ⋯ The relations between component response rates were power functions. Internal consistencies in the data, in conjunction with parallel findings in the literature, suggest that the concept of response strength summarizes the effects of diverse procedures, where response strength is identified with relative resistance to change. The exponent of the power function relating response rates may provide the basis for scaling response strength.
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Three pigeons received training on multiple variable-interval schedules with brief alternating components, concurrently with a fixed-interval schedule of food reinforcement on a second key. Fixed-interval performance exhibited typical increases in rate within the interval, and was independent of multiple-schedule responding. Responding on the multiple-schedule key decreased as a function of proximity to reinforcement on the fixed-interval key. ⋯ To a first approximation, the data were described by a power function, where the exponent depended on the relative rate of reinforcement obtained in the two components. The relative rate of responding in one component of the multiple schedule increased as a function of proximity to fixed-interval reinforcement, and often exceeded the overall obtained relative rate of reinforcement. The form of the function relating response rates is discussed in relation to findings on rate-dependent effects of drugs, chaining, and the relation between response rate and reinforcement rate in single-schedule conditions.