Tests of behavior momentum in simple and multiple schedules with rats and pigeons.
Reinforcement rate only shields behavior from disruption in multiple-schedule setups with clear signals, not in simple schedules.
01Research in Context
What this study did
Cohen et al. (1993) worked with rats and pigeons in two kinds of schedules.
One group got a simple VI schedule. The other got a multiple VI schedule with two clear signals.
The team then gave free food while the animals were working. They watched whose lever or key pecking held up best.
What they found
In the multiple schedule, the component with the richer VI kept responding longer. This is classic momentum.
In the simple schedule, higher reinforcement rate did NOT protect the behavior. Free food washed the effect away.
So momentum only shows up when different stimuli mark each reinforcement rate.
How this fits with other research
Reiss et al. (1982) had already shown that shorter components boost response rate only when they also hold richer pay. The 1993 paper adds: that same pair—clear signals plus rich rate—also shields the behavior from outside disruption.
Rincover et al. (1975) saw free food increase pigeons’ responding but decrease rats’ responding. Cohen et al. (1993) now clarify the picture: species matters, but schedule type matters more. Momentum appears only in the signaled, multiple setup.
Mason et al. (2026) later used a similar multiple schedule and found that extinguishing one component made responding pop up in another. Together these studies say: multiple schedules create strong, stimulus-bound persistence—use them when you want steady performance, but watch for relapse if you change only one part.
Why it matters
If you want a client’s skill to survive distractions, arrange two clear cues and make the target routine the richer one. Simple, single-schedule drills won’t give the same protection. When you later fade reinforcement, adjust both components or you may see resurgence in the wrong place.
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02At a glance
03Original abstract
Four experiments examined the relationship between rate of reinforcement and resistance to change in rats' and pigeons' responses under simple and multiple schedules of reinforcement. In Experiment 1, 28 rats responded under either simple fixed-ratio, variable-ratio, fixed-interval, or variable-interval schedules; in Experiment 2, 3 pigeons responded under simple fixed-ratio schedules. Under each schedule, rate of reinforcement varied across four successive conditions. In Experiment 3, 14 rats responded under either a multiple fixed-ratio schedule or a multiple fixed-interval schedule, each with two components that differed in rate of reinforcement. In Experiment 4, 7 pigeons responded under either a multiple fixed-ratio or a multiple fixed-interval schedule, each with three components that also differed in rate of reinforcement. Under each condition of each experiment, resistance to change was studied by measuring schedule-controlled performance under conditions with prefeeding, response-independent food during the schedule or during timeouts that separated components of the multiple schedules, and by measuring behavior under extinction. There were no consistent differences between rats and pigeons. There was no direct relationship between rates of reinforcement and resistance to change when rates of reinforcement varied across successive conditions in the simple schedules. By comparison, in the multiple schedules there was a direct relationship between rates of reinforcement and resistance to change during most tests of resistance to change. The major exception was delivering response-independent food during the schedule; this disrupted responding, but there was no direct relationship between rates of reinforcement and resistance to change in simple- or multiple-schedule contexts. The data suggest that rate of reinforcement determines resistance to change in multiple schedules, but that this relationship does not hold under simple schedules.
Journal of the experimental analysis of behavior, 1993 · doi:10.1901/jeab.1993.60-255