Short-term and long-term effects of reinforcers on choice (original) (raw)
Related papers
On the joint control of preference by time and reinforcer-ratio variation
Behavioural Processes, 2013
Five pigeons were trained in a procedure in which, with a specified probability, food was either available on a fixed-interval schedule on the left key, or on a variable-interval schedule on the right key. In Phase 1, we arranged, with a probability of 0.5, either a left-key fixed-interval schedule or a rightkey variable-interval 30 s, and varied the value of the fixed-interval schedule from 5 s to 50 s across 5 conditions. In Phase 2, we arranged either a left-key fixed-interval 20-s schedule or a right-key variableinterval 30-s schedule, and varied the probability of the fixed-interval schedule from 0.05 to 1.0 across 8 conditions. Phase 3 always arranged a fixed-interval schedule on the left key, and its value was varied over the same range as in Phase 1. In Phase 1, overall preference was generally toward the variableinterval schedule, preference following reinforcers was initially toward the variable-interval schedule, and maximum preference for the fixed-interval schedule generally occurred close to the arranged fixedinterval time, becoming relatively constant thereafter. In Phase 2, overall left-key preference followed the probability of the fixed-interval schedule, and maximum fixed-interval choice again occurred close to the fixed-interval time, except when the fixed-interval probability was 0.1 or less. The pattern of choice following reinforcers was similar to that in Phase 1, but the peak fixed-interval choice became more peaked with higher probabilities of the fixed interval. Phase 3 produced typical fixed-interval schedule responding. The results are discussed in terms of reinforcement effects, timing in the context of alternative reinforcers, and generalized matching. These results can be described by a quantitative model in which reinforcer rates obtained at times since the last reinforcer are distributed across time according to a Gaussian distribution with constant coefficient of variation before the fixed-interval schedule time, changing to extended choice controlled by extended reinforcer ratios beyond the fixed-interval time. The same model provides a good description of response rates on single fixed-interval schedules.
Journal of the Experimental Analysis of Behavior, 1989
Six pigeons were trained on concurrent variable-interval schedules in which feedback functions arranged that the overall reinforcer rate either (a) was independent of preference, (b) decreased with increasing absolute preference, or (c) increased with increasing absolute preference. In Experiment 1, the reinforcer rate in an interreinforcement interval was determined by the absolute time-allocation ratio in the previous interval. When arranged reinforcer ratios were varied, there was no evidence of control over preference by overall reinforcer rate. In Experiment 2, the feedback function arranged that reinforcer rates were an inverse function of absolute preference, and window durations were fixed times. In Phase 1, using schedules that provided a four-to-one reinforcer ratio, the window duration was decreased from 20 s to 5 s over four conditions. Then, in Phases 2 and 3, the arranged reinforcer ratios were varied. In Phase 2, the reinforcer rate in the current 5-s time window was determined by preference in the previous 5-s window, and in Phase 3, the window durations were 20 s. Again, there was no indication of control by obtained overall reinforcer rate. These data call into question theories that suggest that the process underlying matching is one of maximizing overall reinforcer rates, or that preference in concurrent aperiodic schedules is controlled to any extent by overall reinforcer rate. They also question the notion that concurrent-schedule preference is controlled by molecular maximizing.
2018
Previous studies have challenged the prediction of the Generalized Matching Law about the effect of relative, but not absolute, value of reinforcement parameters on relative choice measures. Six pigeons were run in an experiment involving concurrent variable-interval schedules with unequal reinforcer durations associated with the response alternatives (10 s versus 3s), a systematic replication of Davison (1988). Programmed reinforcement frequency was kept equal for the competing responses while their absolute value was varied. Measures of both response ratios and time ratios showed preference for the larger duration alternative and that preference did not change systematically with changes in absolute reinforcer frequency. Present results support the relativity assumption of the Matching Law. It is suggested that Davison’s results were due to uncontrolled variations in obtained reinforcement frequency. Keywords : choice, preference, overall reinforcer frequency, reinforcer magnitude...
The Response‐Reinforcement Dependency in Fixed‐Interval Schedules of REINFORCEMENT1
Journal of the Experimental Analysis of Behavior, 1970
Pigeons were exposed to four different schedules of food reinforcement that arranged a fixed minimum time interval between reinforcements (60 sec or 300 sec). The first was a standard fixed‐interval schedule. The second was a schedule in which food was presented automatically at the end of the fixed time interval as long as a response had occurred earlier. The third and fourth schedules were identical to the first two except that the first response after reinforcement changed the color on the key. When the schedule required a peck after the interval elapsed, the response pattern consisted of a pause after reinforcement followed by responding at a high rate until reinforcement. When a response was not required after the termination of the interval, the pattern consisted of a pause after reinforcement, followed by responses and then by a subsequent pause until reinforcement. Having the first response after reinforcement change the color on the key had little effect on performance. Pos...
Choice and the Initial Delay to a Reinforcer
The Psychological Record, 2008
Pigeons were trained in two experiments that used the concurrent-chains procedure. These experiments sought to identify the variables controlling the preference of pigeons for a constant duration over a variable duration of exposure to an aperiodic, time-based, terminal-link schedule. The results indicated that two variables correlated with the constant-duration terminal link combined to control preference: (a) a shorter initial delay to a reinforcer; and (b) the probabilistic occurrence of multiple reinforcers. Grace and Nevin (2000) trained pigeons on a concurrent-chains procedure with equal variable-interval (VI) schedules in the initial links and equal VI schedules in the terminal links. The terminal links differed in that one ended after a single reinforcer, which they called "variable-duration" terminal link, whereas the other ended after a fixed period of exposure equal to the average interreinforcement interval (IRI) of the schedule, which they called "constantduration" terminal link. As Grace and Nevin identified, and as discussed at some length below, an important feature of the constant-duration terminal link is that it probabilistically yielded 0, 1, or multiple reinforcers per entry, although it provided the same average rate of reinforcement overall as the variable-duration terminal link. Grace and Nevin (2000) found that three of four pigeons clearly preferred the constant-duration terminal link. In their words, the data of a fourth pigeon "demonstrated a consistent right-key bias" (p. 178), and the present conclusion is that its data are more difficult to interpret. In any case, an important question is what variables caused the preference. Ordinarily, one would have expected the pigeons to be indifferent, since the schedules in effect during the alternatives were identical, and each alternative yielded the same overall rate of reinforcement. Grace and Nevin (2000) initially pondered the role of multiple reinforcers in the constant-duration terminal link, because research has shown that subjects may well prefer a choice alternative associated with multiple reinforcers rather than a single reinforcer per terminal-link entry (e.g.,
Some effects of reinforcer availability on the pigeon’s responding in 24-hour sessions
Animal Learning & Behavior, 1981
Restrictions on food availability produced by schedules of reinforcement were examined in three homing pigeons continuously housed in operant chambers. Total daily access to food was free to vary and depended on the subject's contact with the schedule in effect. Experiment 1 varied reinforcer duration within a continuous reinforcement schedule in order to provide a description of the pigeon's feeding pattern under minimal constraints. In Experiments 2 and 3, access to food was contingent on responding in fixed-interval schedules, and limits on availability of food were varied by changing the duration of reinforcement (Experiment 2) or the frequency of reinforcement (Experiment 3l. In all three experiments, a decline in the scheduled availability of food produced an increase in both the overall response rate and the local response rate. In addition, the distribution of responding across the day followed a diurnal rhythm typical of the pigeon's unconstrained pattern of food intake. These effects are consistent with previous studies showing an inverse relationship between instrumental response rate and reinforcer availability in the absence of fixed deprivation, and support the interpretation that this inverse relationship results from constraints imposed on preferred patterns of intake. The data on the localdistribution of responses were consistent with an extension of the response-deprivation hypothesis to localresponse patterning. 411