Pausing under variable-ratio schedules: Interaction of reinforcer magnitude, variable-ratio size, and lowest ratio.
Small reinforcers make learners pause longer when ratios get tough, so boost magnitude or shrink the lowest ratio to keep momentum.
01Research in Context
What this study did
The team put rats on variable-ratio (VR) schedules. The animals pressed a lever for food.
They changed three things at once: how big each food pellet was, how large the VR got, and the smallest ratio that could appear.
Each rat served as its own control. Sessions ran until rates were steady.
What they found
With tiny 2-second pellets, bigger VR sizes and bigger lowest ratios made rats pause longer after food.
With large 6-second pellets, those same changes barely touched pause time.
Run rate only dipped a little as ratios grew, but bigger food kept it slightly higher.
How this fits with other research
CATANIDINSMOOR (1962) first showed less food makes animals slower to start. Charlop et al. (1990) now prove the rule holds only when reinforcers are already small.
Davis et al. (1972) found long signaled delays also stretch pauses. The new study swaps delay for ratio size and shows magnitude decides whether the pause grows.
Xue et al. (2024) moved the pause idea into an autism classroom: even 4-8 s delays slow tact learning. Together the three papers say the same thing across lab and clinic—keep the reinforcer big or keep it fast.
Why it matters
If your client stalls after reinforcement, check both size and schedule. A thin VR 20 with a single M&M can create long post-reinforcement pauses. Bump the magnitude or tighten the lowest ratio and work should restart sooner.
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02At a glance
03Original abstract
Pigeons pecked a key under two-component multiple variable-ratio schedules that offered 8-s or 2-s access to grain. Postreinforcement pausing and the rates of responding following the pause (run rates) in each component were measured as a function of variable-ratio size and the size of the lowest ratio in the configuration of ratios comprising each schedule. In one group of subjects, variable-ratio size was varied while the size of the lowest ratio was held constant. In a second group, the size of the lowest ratio was varied while variable-ratio size was held constant. For all subjects, the mean duration of postreinforcement pausing increased in the 2-s component but not in the 8-s component. Postreinforcement pauses increased with increases in variable-ratio size (Group 1) and with increases in the lowest ratio (Group 2). In both groups, run rates were slightly higher in the 8-s component than in the 2-s component. Run rates decreased slightly as variable-ratio size increased, but were unaffected by increases in the size of the lowest ratio. These results suggest that variable-ratio size, the size of the lowest ratio, and reinforcer magnitude interact to determine the duration of postreinforcement pauses.
Journal of the experimental analysis of behavior, 1990 · doi:10.1901/jeab.1990.53-133