A DETAILED ANALYSIS OF THE EFFECTS OF d‐AMPHETAMINE ON BEHAVIOR UNDER FIXED‐INTERVAL SCHEDULES 1

Key pecking by three pigeons was maintained under a multiple fixed-interval fixed-ratio schedule of food presentation. The fixed-interval value remained at 3 minutes, while the fixed-ratio size was increased systematically in 30-response increments from 30 to either 120 (two pigeons) or 150 (one pigeon). At least two lower fixed-ratio values were also redetermined. The effects of ethanol (.5 to 2.5 g/kg) were assessed at each of the different schedule parameters. Both overall and running response rates under the fixed-ratio schedule decreased with increases in the size of the fixed-ratio schedule; pause duration under the fixed-ratio schedule was directly related to increases in fixed-ratio size. Overall and running rates of responding under the fixed-iinterval schedule changed little with increases in the size of the fixed-ratio schedule. Despite the relative invariance of fixed-interval responding across the different fixed-ratio values, the effects of ethanol on responding under the fixed-interval schedule differed depending on the size of the fixed-ratio schedule. Greater increases occurred in both overall and in lower local rates of responding under the fixedinterval schedule when the fixed-ratio value was 120 or 150. The effects of ethanol on responding under the fixed-ratio schedule also depended on the size of the fixed ratio.Increases in responding under the fixed-ratio schedule were typically greater at the higher fixed-ratio values where response rates were lower. When the effects of ethanol were redetermined at the lower fixed-ratio parameter values, rates and patterns of responding were comparable to those obtained initially. However, the dose-effect curves for responding under both fixed-ratio and fixed-interval schedules were shifted up and to the right of those determined during the ascending series. The effects of ethanol can depend on rate of responding, behavioral history, and the context in which behavior occurs.

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of Ethanol on Multiple Fixed‐interval Fixed‐ratio Schedule Performances: Dynamic Interactions at Different Fixed‐ratio Values

Barrett

Stanley

1980

“…Evaluations of patterning based on data grouped over multiple intervals typically have been misleading about the nature of behavior as it occurs in individual intervals. Branch and Gollub (1974) showed that the averaged data need not correspond with behavior occurring in any individual interval.The peak procedure can show the sensitivity of animals to time both before and after the fixed interval has elapsed, because it involves interpolated trials uninterrupted by food delivery. What is missing is information about behavior on each empty trial.…”

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confidence: 99%

Temporal Control in Fixed‐interval Schedules

Zeiler

Powell

1994

The peak procedure was used to study temporal control in pigeons exposed to seven fixed-interval schedules ranging from 7.5 to 480 s. The focus was on behavior in individual intervals. Quantitative properties of temporal control depended on whether the aspect of behavior considered was initial pause duration, the point of maximum acceleration in responding, the point of maximum deceleration, the point at which responding stopped, or several different statistical derivations of a point of maximum responding. Each aspect produced different conclusions about the nature of temporal control, and none conformed to what was known previously about the way ongoing responding was controlled by time under conditions of differential reinforcement. Existing theory does not explain why Weber's law so rarely fit the results or why each type of behavior seemed unique. These data fit with others suggesting that principles of temporal control may depend on the role played by the particular aspect of behavior in particular situations.Key words: peak procedure, timing, fixed-interval schedules, key peck, pigeonsThe peak procedure was devised by Catania (1970) to study temporal control under fixedinterval (FI) schedules. In an FI schedule, food delivery follows the first response emitted after a specified (and constant) time period has elapsed. If response rate is based on stimulus generalization along the dimension of elapsed time, the point of highest rate presumably reflects when the animal estimates that food is available. By adding empty trials with food omitted and trial length extended well beyond the end of the interval, the peak procedure makes it possible to determine where responding is maximal.Catania (1970) and others (e.g., Maricq, Roberts, & Church, 1981;Meck, Komeily-Zadeh, & Church, 1984;Roberts, 1981Roberts, ,1982Roberts & Holder, 1984) found that the point of peak rate rarely departed by more than 10% from the Fl value, thereby suggesting highly accurate temporal control by the time of food availability. In all of these experiments, peak time was calculated from data cumulated over numerous empty trials. However, the contemporary view (Gibbon & Church, 1990 temporally controlled starting and stopping times over numerous empty trials. The result of this averaging is to generate smooth response-rate curves with well-defined peaks that do not correspond to the long periods of steady response rate without any peak that actually occur in individual trials. This should not be surprising in light of earlier observations about temporal patterning in FI schedules. Evaluations of patterning based on data grouped over multiple intervals typically have been misleading about the nature of behavior as it occurs in individual intervals. Branch and Gollub (1974) showed that the averaged data need not correspond with behavior occurring in any individual interval.The peak procedure can show the sensitivity of animals to time both before and after the fixed interval has elapsed, because it involves interpolated trials uninterrupte...

“…Break-and-run patterns (Cumming & Schoenfeld, 1958;Schneider, 1969), on the other hand, are typified by an abrupt transition from little or no responding to a high and relatively constant response rate. Whether this type of pattern is actually distinct from scalloping has been called into question by subsequent analysts (Branch & Gollub, 1974;Dews, 1979;Lowe & Harzem, 1977). The oscillatory, "pause-respond" pattern characteristic of animal performance-whether it be of the scalloping or break-and-run varieties-is often considered indicative of sensitivity to the temporal structure of the FL contingency.…”

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confidence: 99%

Effects of Instructional Constraints on Human Fixed‐interval Performance

Buskist

Bennett

Miller

1981

Several groups of human subjects were exposed to a variety of experimental conditions involving a fixed-interval 27-second schedule of reinforcement in compound with instructions to constrain in the number of responses within the interreinforcement interval and/or the duration of the experimental session. One group was further exposed to a contingency involving the placement of responses within the IRI. A diversity of patterns of performance was observed, including those typically associated with animal subjects exposed to Fl schedules. Generally, the imposition of instructions to minimize session duration reduced postreinforcement pausing and increased overall reinforcement density from those levels obtained with only instructions to expend a given number of responses per reinforcer. The results are seen to underscore the sensitivity of human fixed-interval performance and the contribution of extra-experimental contingencies.