RESPONSE‐RATE INVARIANCE IN CONCURRENT SCHEDULES: EFFECTS OF DIFFERENT CHANGEOVER CONTINGENCIES<sup>1</sup>

Guilkey, Marilyn; Shull, Richard L.; Brownstein, Aaron J.

doi:10.1901/jeab.1975.24-43

Cited by 11 publications

(15 citation statements)

References 20 publications

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“…Similar results were reported by Bourland and Miller (1978) and Killeen (1972). On the other hand, Guilkey, Shull, and Brownstein (1975) and White (1979) failed to observe this rate difference when they used a FR changeover requirement. Pliskoff, Cicerone, and Nelson (1978) …”

Section: ()Jsupporting

confidence: 83%

“…Second, it was consistently found that the differences between COD and post-COD response rates were greatly reduced when a COD of variable, rather than fixed, duration was used. Other researchers (Guilkey et al, 1975;Pliskoff et al, 1978;White, 1979) have also failed to obtain a substantial increase in response rates immediately after the CO response when they used a FR changeover requirement instead of a COD of fixed duration. The results of their experiments together with the present findings indicate that elevated response rates immediately after the CO response may occur only when a COD of fixed duration is used.…”

Section: Resultsmentioning

confidence: 99%

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The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

Haaren

1981

Animal Learning & Behavior

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()()JThe effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons were investigated in a series of three experiments. Experiment 1 compared the effects of a fixed, variable, or variable signaled changeover delay on interchangeover times and responding during and after the changeover delay. The duration of the changeover delays was systematically varied in Experiment 2, and the relative reinforcement frequencies were manipulated in Experiment 3. Interchangeover times were found to be shorter when changeover delays of variable duration were compared with those of fixed duration. Changeover delays of fixed duration produced higher response rates during the changeover delay than after the changeover delay had elapsed; changeover delays of variable duration produced such differences to a lesser extent. It was concluded that the changeover delay in concurrent variableinterval schedules of reinforcement functionally acts as a delay period to the next opportunity for reinforcement, possibly serving as a conditioned reinforcer for the behavior preceding it (the interchangeover time) and as a discriminative stimulus for the behavior in its presence (response rates during the delay).Two different methods of programming concurrent schedules of reinforcement have been widely used. In one of these (Findley, 1958), responding is maintained on one (main) key, while the subject switches schedules by responding on a second (changeover) key; each schedule on the main key is associated with its own discriminative stimulus. In the other method (Herrnstein, 1961), responding is maintained on two separate response manipulanda, each associated with its own schedule of reinforcement. Matching between relative reinforcement variables and relative performance measures has been demonstrated extensively with both kinds of procedures (DeVilliers, 1977).It has been found that a changeover delay (COD) is necessary if matching is to be obtained. A COD specifies a minimum amount of time that has to elapse between a changeover (CO) response and a subsequently reinforced response. The presence of a COD effectively eliminates the possibility of immediately reinforcing response sequences that include a CO response (Catania, 1966).Several factors affect the number of CO responses

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Section: ()Jsupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

Haaren

1981

Animal Learning & Behavior

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“…In general, the two methods have similar effects: the matching re-239 1979,31,[239][240][241][242][243][244][245][246][247][248][249][250][251][252] NUMBER 2 (MARCH) lation is found when either is used, and increasing the value of each has a similar effect on changeover and response rates. One important difference noted by Guilkey et al (1975) is that the COR does not produce the postchangeover bursts of responding which occur during the COD. With respect to this, it should be recognized that the COD is imposed after the requirement for switching has been met, whereas the COR is simply a requirement for switching.…”

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confidence: 98%

“…Thus reinforcements on one schedule are separated from responses on the other by a series of responses on the changeover manipulandum. Comparisons of the use of a COR and a COD in concurrent variable-interval (VI) schedules have been made by Guilkey, Shull, and Brownstein (1975) and Stubbs and Pliskoff (1969), both using pigeons. In general, the two methods have similar effects: the matching re-239 1979,31,[239][240][241][242][243][244][245][246][247][248][249][250][251][252] NUMBER 2 (MARCH) lation is found when either is used, and increasing the value of each has a similar effect on changeover and response rates.…”

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confidence: 99%

CHANGEOVER RATIO EFFECTS ON CONCURRENT VARIABLE‐INTERVAL PERFORMANCE¹

White

1979

J Exper Analysis Behavior

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Rats' bar-pressing was maintained by concurrent variable-interval schedules of reinforcement. A fixed-ratio of pulls on a chain (the changeover ratio) was required for switching between schedules. The first experiment employed equal variable-interval schedules and symmetrical changeover ratios. Increasing these ratios resulted in a decrease in the rate of switching between schedules and an increase in local response rate. In the second experiment, a range of asymmetrical changeover ratios was used with equal variableinterval schedules, and a preference wvas found for the schedule associated with the larger switching-into ratio. Both the distributions of responses and time between the two schedules deviated from those expected on the basis of obtained reinforcers. In the third experiment, the switching-out-of ratio was dependent on the amount of time spent in a variable-interval 2-minute schedule; a constant ratio permitted switching out of the alternative variable-interval 1-minute schedule. A strong preference was shown for the variable-interval 2-minute schedule. The fourth experiment used equal variable-interval schedules; one changeover ratio was varied while the second remained constant. The results failed to show systematic differences in local response rates immediately after a changeover.Key words: changeover ratio, concurrent schedules, matching, variable-interval, chainpull, lever press, rats Two methods have been used for programming schedules associated with concurrent operants: one involves a separate manipulandum for each of the operants, with the restriction that responding simultaneously on two or more manipulanda is not possible; the other provides a distinct manipulandum for switching between schedules, with two or more operants performed on another manipulandum, each associated with different stimulus conditions. Results from these two methods appear to be equivalent over a wide range of experimental manipulations (Catania, 1966

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“…For example, the changeover delay or COD (Herrnstein, 1961) arranges a time interval after each changeover from one response to the other, during which no response can be reinforced. But although a COD may reduce the likelihood that either response is maintained by reinforcers scheduiled for the other, it also affects the rate and pattern of responding immediately after the changeover (Catania, 1972;Guilkey, Shull, and Brownstein, 1975;Pliskoff, 1971;Silberberg and Fantino, 1970). Thus, the properties of concurrent performances may depend critically on whether and at what delay value a COD operates (Catania, 1962(Catania, , 1963Shull and Pliskoff, 1967).…”

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CONCURRENT PERFORMANCES: RATE CONSTANCIES WITHOUT CHANGEOVER DELAYS¹

Catania

1976

J Exper Analysis Behavior

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Pigeons' pecks on two keys were maintained, without changeover delays, by independent variable-interval schedules of food reinforcement. Four regularly cycling 2-min components scheduiled reinforcement respectively for both keys, left key only, both keys, and right key only. Initially, reinforcement scheduled for one key alone produced more responding on that key than reinforcement scheduled concurrently for both keys. Continued sessions reduced this difference; response rate on a given key approached constancy, or invariance with respect to the performance on and schedule for the other key. When extinction replaced the reinforcement schedule on either key, responding on that key decreased more during components that scheduled reinforcement for the other key than during those that did not. This demonstration that responses on one key were not supported by reinforcers on the other key suggested that the alternation of concurrent responding and either-key-alone responding prevented concurrent superstitions from developing.Key words: concurrent schedules, multiple schedules, variable-interval schedules, changeover delays, rate constancy, concurrent superstition, response independence, key peck, pigeonThe obvious criterion for independence of concurrent responses is that the rate of each response is unaffected by changes in either the rate of the other response or the reinforcers produced by the other response. But concurrent schedules may generate contingencies that operate against such independence. For example, when a pigeon's pecks on two keys are reinforced concurrently according to independent variable-interval (VI) schedules, the probability that a peck on one key will be reinforced increases with time spent in pecking the other key. For this reason, reinforced pecks on one key may often follow closely on changeovers from the other key. But the reinforcer may then act on the sequence of pecks on the two keys. Once this happens, the concurrent performances cannot be independent, because each response is partially under the control of the reinforcers scheduled for the other (cf.

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RESPONSE‐RATE INVARIANCE IN CONCURRENT SCHEDULES: EFFECTS OF DIFFERENT CHANGEOVER CONTINGENCIES¹

Cited by 11 publications

References 20 publications

The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

CHANGEOVER RATIO EFFECTS ON CONCURRENT VARIABLE‐INTERVAL PERFORMANCE¹

CONCURRENT PERFORMANCES: RATE CONSTANCIES WITHOUT CHANGEOVER DELAYS¹

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RESPONSE‐RATE INVARIANCE IN CONCURRENT SCHEDULES: EFFECTS OF DIFFERENT CHANGEOVER CONTINGENCIES1

Cited by 11 publications

References 20 publications

The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons

CHANGEOVER RATIO EFFECTS ON CONCURRENT VARIABLE‐INTERVAL PERFORMANCE1

CONCURRENT PERFORMANCES: RATE CONSTANCIES WITHOUT CHANGEOVER DELAYS1

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RESPONSE‐RATE INVARIANCE IN CONCURRENT SCHEDULES: EFFECTS OF DIFFERENT CHANGEOVER CONTINGENCIES¹

CHANGEOVER RATIO EFFECTS ON CONCURRENT VARIABLE‐INTERVAL PERFORMANCE¹

CONCURRENT PERFORMANCES: RATE CONSTANCIES WITHOUT CHANGEOVER DELAYS¹