Changeover delay and concurrent schedules: some effects on relative performance measures.
A longer changeover delay nudges learners toward the richer schedule and cuts switching—use brief delays for balanced responding.
01Research in Context
What this study did
Shull et al. (1967) worked with pigeons on two VI key-peck schedules running at the same time.
A changeover delay (COD) punished quick switches. The team lengthened that delay to see how it changed the birds’ choices and how often they jumped keys.
What they found
Longer CODs pushed more pecks toward the richer VI 1-min side.
The birds also switched keys less often.
When both schedules paid at the same rate, choice stayed at 50-50 no matter the delay.
How this fits with other research
Smith et al. (1975) ran almost the same pigeon set-up and still saw mismatches between response ratios and payoff ratios. Their data back up the 1967 finding that strict matching is rare.
Durand (1982) swapped the COD for a short walk between keys. Travel time, like COD, cut switches and strengthened bias toward the richer side. The two studies line up: any added switch cost steers behavior the same way.
Renne et al. (1976) moved the task to adult humans pressing buttons. People still followed Herrnstein’s equation, showing the pigeon rule holds across species.
Why it matters
When you set up concurrent reinforcement, remember that even a tiny switch penalty can tilt client responding. If you want balanced work across tasks, keep the COD short or remove extra travel steps. If you need to strengthen one task, a brief delay after a switch can do the job without extra tokens or praise.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Trim any built-in pause or travel time between two work options to see more even responding during your next reinforcer test.
02At a glance
03Original abstract
The pigeon and the rat partition total response output between both schedules of a concurrent variable-interval pair. The quantitative nature of a partition seems critically dependent on the relative rates with which the two schedules provide reinforcements for responding, in addition to the changeover delay. The manner in which the changeover delay controls the partition was studied by varying the duration of the changeover delay from 0 to 20 sec with each of two pairs of concurrent variable-interval schedules, viz., Conc VI 1.5-min VI 1.5-min and Conc VI 1-min VI 3-min. Rats served as the subjects and brain stimulation was employed as the reinforcer. When the schedules were Conc VI 1.5-min VI 1.5-min, relative response rate approximated 0.50 at all values of the changeover delay. When the schedules were Conc VI 1-min VI 3-min, relative response rate, computed with respect to the VI 1-min schedule, increased when the duration of the changeover delay increased. Changeover rate decreased when the duration of the changeover delay increased. The decrease was the same for both VI schedules of the Conc VI 1.5-min VI 1.5-min pair but was more rapid for the VI 3-min schedule of the Conc VI 1-min VI 3-min pair.
Journal of the experimental analysis of behavior, 1967 · doi:10.1901/jeab.1967.10-517