PROBABILITY RELATIONS WITHIN RESPONSE SEQUENCES UNDER RATIO REINFORCEMENT1 (original) (raw)
Related papers
European journal of behavior analysis, 2017
This experiment examined resistance to change of the different response positions of three-response sequences (left/middle/right button presses) exhibited by a group of children when contingencies were shifted from continuous reinforcement to a lag or yoked reinforcement schedule. A backward progression of extinction for the three-response sequences was observed for all subjects under the lag schedule, suggesting that the role of extinction should be reconsidered as an explanation for increased variability observed under lag schedules. We suggest that variability may be, at least partly, explained by the documented effects of responses undergoing extinction rather than characterize variability as an operant dimension that can be reinforced per se.
The distribution of response bout lengths and its sensitivity to differential reinforcement
Journal of the Experimental Analysis of Behavior, 2015
Response bouts are clusters of responses that occur in rapid succession and are punctuated by pauses during which the response does not occur. Under variable interval schedules of reinforcement, the number of responses in each bout (the bout length) varies among bouts. This experiment was aimed at determining whether the relative rate of reinforcement influenced the relative frequency of bouts of different lengths. Lever pressing in rats was reinforced under a tandem variable time (VT) 150-s fixed ratio (FR) X, where X could be 1 or 5 and varied randomly after each reinforcer. Two conditions were included: majority FR1 (mFR1) and majority FR5 (mFR5). In mFR1, 75% of reinforcers had a tandem FR requirement of 1 and 25% had a tandem FR requirement of 5; this distribution was reversed in mFR5. The dynamic bi-exponential refractory model of response bouts was fitted to the interresponse times (IRTs) in each condition. Model parameter estimates and IRTs were then used to simulate probable distributions of bout lengths. These distributions comprised a mixture of short geometrically-distributed bout lengths and long negative-binomially-distributed bout lengths. Long bouts were significantly longer in the mFR5 condition than in the mFR1 condition. In conjunction with previous data, the present study suggests that the prevalence of long bouts increases with the proportion of reinforcers with FR5 requirement. These results suggest that bouts of different lengths are sensitive to the rate at which they are reinforced.
Journal of the Experimental Analysis of Behavior, 2008
This study focused on variables that may account for response-rate differences under variable-ratio (VR) and variable-interval (VI) schedules of reinforcement. Four rats were exposed to VR, VI, tandem VI differential-reinforcement-of-high-rate, regulated-probability-interval, and negative-feedback schedules of reinforcement that provided the same rate of reinforcement. Response rates were higher under the VR schedule than the VI schedule, and the rates on all other schedules approximated those under the VR schedule. The median reinforced interresponse time (IRT) under the VI schedule was longer than for the other schedules. Thus, differences in reinforced IRTs correlated with differences in response rate, an outcome suggestive of the molecular control of response rate. This conclusion was complemented by the additional finding that the differences in molar reinforcement-feedback functions had little discernible impact on responding.
Persistence of Response Variation and Repetition
A multiple chained schedule was used to assess the persistence of fixed and variable response sequences. In one terminal link, a single 4-peck response sequence produced food (Repeat) and in the other terminal link a 4-peck response sequence produced food only if it had been occurring infrequently relative to the other 15 possible responses (Vary). Similar response and reinforcement rates occurred in each terminal link. Identical variable-interval 20-s schedules operated in the initial links preceding each terminal link and lower response rates reliably occurred in the initial link preceding the Vary terminal link. After responding stabilized under the multiple chained schedule, four disruption conditions were employed, one condition in which each pigeon was pre-fed before each session and three conditions in which a variable-time schedule, of three different values, operated during the inter-component intervals that preceded each initial link. During each of the four disruption conditions, response rate in each link of the chained schedule in the Vary component tended to be more persistent, relative to its own baseline level, than response rate in the Repeat component. During the pre-feeding condition, relative to baseline, the amount of variation in the Vary terminal link decreased slightly and the amount of repetition in the Repeat component remained similar. During the variable-time-schedule conditions, the amount of variation in the Vary component remained similar or decreased slightly, relative to baseline, while the amount of repetition in the Repeat component increased considerably. These results extend earlier findings demonstrating that response repetition is more susceptible to environmental disruption than is response variation. The results also suggest that theories of response strength, such as behavioral momentum theory, must take into account different response topographies. Persistence of Response Variation and Repetition Table of Contents Chapter 1-Overview ……………………………………………………………… 1-13 Introduction ……………………………………………………………….. 1-2 Literature Review …………………………………………………………. 2-12 Response Repetition …………………………………………… 2-5 Response Variation ……………………………………………. 5-9 Response Strength ……………………………………………... 9-12 Statement of the Problem …………………………………………………. 12-13 Chapter 2-Experimental Method and Results ……………………………………. 14-35 Method ……………………………………………………………………. 14-18 Subjects …………………………………………………………………… 14 Apparatus …………………………………………………………………. 14
Learning and Motivation, 1999
Pigeons (Experiment 1) and rats (Experiment 2) responded on variable interval (VI), variable time (VT), and extinction procedures. All three procedures were conducted for three different baseline rates of reinforcement. When the rates of reinforcement obtained from the VI and VT schedules did not differ significantly, the within-session patterns of responding observed on the two procedures did not differ. Both of these patterns differed from the patterns observed during extinction. These results are consistent with the argument that sensitization-habituation contributes to within-session patterns of responding during both conditioning and extinction and that subjects may sensitize and habituate to contextual stimuli as well as to reinforcers. The results help to explain why spontaneous recovery is not always observed during random reinforcement procedures. They also suggest that the factors governing within-session patterns of responding are independent of the factors governing absolute response rates.
Responding under discrete-trial fixed-interval schedules of reinforcement1
Journal of the Experimental Analysis of Behavior, 1972
A fixed-interval schedule of reinforcement was modified by dividing each interval into -4-sec trial periods. No more than one response could occur during each trial because the operandum was inactivated for the remainder of any trial in which a response occurred. For example, under a 28-sec schedule, no more than seven responses could be emitted between reinforcements. Probabilities of responding by pigeons under six values of this discrete-trial fixed-interval schedule were best described by a two-state model: responding was either absent or infrequent immediately after reinforcement; then, at some variable time after reinforcement, there was an abrupt transition to a high and constant probability of responding on each trial. Performances under the discrete-trial procedure were less affected by uncontrolled sources of variance than performances under equivalent freeoperant fixed-interval schedules.
A comparison of response patterns on fixed-, variable-, and random-ratio schedules
Journal of the Experimental Analysis of Behavior, 1987
The behavior of individual pigeons on fixed-ratio, variable-ratio, and random-ratio schedules was examined. Within each type of ratio schedule the size of the ratio was varied in an irregular sequence. At various ratio sizes (5, 10, 40, 80) no differences were found among overall response rates (postreinforcement pause plus running response rate) as a function of ratio type. This similarity in overall response rates held despite noticeable differences in the microstructure of performance both within and across subjects; the primary performance difference on the three types of ratio schedules was the relatively longer postreinforcement pause duration on the fixed-ratio schedule. We concluded that the gross temporal characteristics of performance determined by the relative weightings of the postreinforcement pause and running response rate were primarily controlled by the type of ratio schedule (fixed, variable, or random), whereas the overall rate of responding was controlled by the size of the ratio.
2008
Rats were trained on mixed-fixed-interval (FI) schedules, with component FIs of 30 and 60 s. The probability of reinforcement according to FI 30 s varied between conditions, across values of 0.1, 0.3, 0.5, 0.7 and 0.9. When response rate in the 60 s intervals was measured, separate response peaks, one close to 30 s, the other at 60 s, could be identified when the probability of reinforcement at 30 s was 0.3 or greater. Nonlinear regression found that the location of the earlier peak was always close to 30 s, that the coefficient of variation of the response functions at 30 and 60 s were unaffected by reinforcement probability, but that the 30 s component appeared to be timed slightly more precisely than the 60 s one. Response rate at around 30 s increased with increasing probability of reinforcement according to FI 30 s, but responding at 60 s was unaffected by reinforcement probability. The data are discussed with respect to a number of contemporary models of animal timing (scalar expectancy theory, the Behavioural Theory of Timing and the Learning to Time model), and a recent account of response output on FI-like schedules.
A Runs-Test Algorithm: Contingent Reinforcement and Response Run Structures
Journal of the Experimental Analysis of Behavior, 2010
Four rats' choices between two levers were differentially reinforced using a runs-test algorithm. On each trial, a runs-test score was calculated based on the last 20 choices. In Experiment 1, the onset of stimulus lights cued when the runs score was smaller than criterion. Following cuing, the correct choice was occasionally reinforced with food, and the incorrect choice resulted in a blackout. Results indicated that this contingency reduced sequential dependencies among successive choice responses. With one exception, subjects' choice rule was well described as biased coin flipping. In Experiment 2, cuing was removed and the reinforcement criterion was changed to a percentile score based on the last 20 reinforced responses. The results replicated those of Experiment 1 in successfully eliminating first-order dependencies in all subjects. For 2 subjects, choice allocation was approximately consistent with nonbiased coin flipping. These results suggest that sequential dependencies may be a function of reinforcement contingency.