Journal of the experimental analysis of behavior
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Three rats were trained on an unsignalled shuttlebox-avoidance task under three response-shock intervals (10, 20, and 40 sec). Under all conditions, subjects developed excellent temporal gradients of avoidance; that is, response rate was an increasing function of time since last response. ⋯ In all cases, response rate relative to the maximum response rate was approximately equal to the proportion of the interval that had elapsed. This suggests that rats in unsignalled avoidance are estimating time from response completion, and that the units of the estimate are proportional parts of the response-shock interval.
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For three pigeons, reinforcement depended upon a left side-key response after execution of a fixed ratio 10 on the center key, and upon a right side-key response after fixed ratio 20. Each response during the fixed ratios produced a 0.5-sec blackout. ⋯ When the time between the first and last response was equated during both ratios, asymptotic accuracy was approximately equal to (two birds) or somewhat higher than (one bird) that obtained previously. The results of probes with intermediate fixed ratios and blackouts suggested that control of side-key choice had transferred from the time between the first and last response in ratios to blackout duration.