Independence of concurrent responding maintained by interval schedules of reinforcement.
Add a short changeover delay when you run two schedules at once; it keeps each response pattern pure.
01Research in Context
What this study did
The team ran two schedules at the same time. One schedule paid every few minutes no matter how many responses. The other paid only after a fixed time.
They let the subject switch between the two levers whenever it wanted. Sometimes they added a short pause after each switch.
What they found
When the pause was on, each schedule kept its own pattern. The bird pecked as if the other lever did not exist.
When the pause was off, the patterns mixed. Quick bursts showed up where they did not belong.
How this fits with other research
Cohen (1975) looked closer at the tiny bursts. He saw that time on each lever, not the peck speed, sets the local pattern.
Reid et al. (1983) pooled many studies. They found that long pauses let the local pay rates line up, matching the birds’ time split.
Geckeler et al. (2000) added a twist. Kids with autism worked harder when they could pick their prize, but only under the same two-lever setup.
Why it matters
If you run two teaching tasks side-by-side, drop in a 3-second changeover delay. The brief wait keeps each skill’s response pattern clean. You will see true performance on both tasks instead of messy carry-over.
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02At a glance
03Original abstract
A pigeon's responses were reinforced on a variable-interval schedule on one key; and, concurrently, either a multiple or a fixed-interval schedule of reinforcement was in effect on a second key. These concurrent schedules, conc VI 3 (mult VI 3 EXT) or conc VI 3 FI 6, were programmed with or without a changeover delay (COD). Because the COD provided that responses on one key could not be followed by reinforced responses on the other key, responding on one key was not likely to accidentally come under the control of the reinforcement schedule on the other. When the COD was used, the performances on each key were comparable to the performances maintained when these interval schedules are programmed separately. The VI schedule maintained a relatively constant rate of responding, even though the rate of responding on the second key varied in a manner appropriate to the schedule on the second key. The mult VI 3 EXT schedule maintained two separate rates of responding: a relatively high rate during the VI 3 component, and almost no responding during the EXT component. The FI schedule maintained the gradually increasing rate of responding within each interval that is characteristic of the performance maintained by this schedule. The concurrent performances, however, did include certain interactions involving the local characteristics of responding and the over-all rates of responding maintained by the various schedules. The relevance of the present findings to an inter-response time analysis of VI responding, a chaining account of FI responding, and the concept of the reflex reserve was discussed.
Journal of the experimental analysis of behavior, 1962 · doi:10.1901/jeab.1962.5-175