Effects of magnitude of food reinforcement on free-operant response rates.
Bigger food reinforcers on VR schedules push faster response runs but also stretch the post-reinforcement pause.
01Research in Context
What this study did
Reed et al. (1988) worked with rats pressing a lever for food. They kept the schedule the same (VR) but changed the size of each food pellet. Bigger pellets meant bigger reinforcers.
The team tracked two things: how fast the rats pressed during each run, and how long they paused right after eating.
What they found
Larger food pellets made the rats press faster during the run. The same big pellets also made the rats wait longer before they started pressing again.
So bigger rewards speed you up and then make you take a longer break.
How this fits with other research
Charlop et al. (1990) ran almost the same VR setup and saw the same longer pauses with bigger pellets. Their extra twist: when the VR requirement itself got larger, the pause grew even more, but only if the pellet was small.
Reed (1991) extended the idea to other schedules. On simple VI schedules, bigger pellets actually slowed the rats down. The boost seen here only shows up on ratio schedules.
Foltin (1997) looks like a contradiction: longer access to running as a reinforcer cut lever pressing, not raised it. The key difference is the type of reinforcer—wheel-running versus food—so bigger is not always better.
Why it matters
When you want rapid responding on a ratio program, deliver the largest practical edible or token. Expect a short pause right after; use that pause to reset materials or give instruction. If you shift to interval or choice schedules, test first—bigger may back-fire and slow the client down.
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Join Free →Increase the size or number of edibles per token on VR-based token boards and watch for a longer post-reinforcement pause—use that pause to reset materials.
02At a glance
03Original abstract
In Experiment 1 rats were trained to press a lever on a variable-ratio schedule of food presentation and were then exposed to progressively increasing magnitudes of food reinforcement. Response running rates (rates exclusive of the postreinforcement pause) were found to increase as a function of increasing reinforcement magnitudes. The effect of reinforcement magnitude on response rates inclusive of the postreinforcement pause, however, was less pronounced. Increases in the magnitude of reinforcement were also found to increase the length of the postreinforcement pause. Rats in Experiment 2 were trained to respond on a chained differential-reinforcement-of-low-rate variable-ratio schedule, and were exposed to increasing magnitudes of reinforcement as in Experiment 1. Response running rates increased in the variable-ratio component but decreased in the other component of the schedule. The results are discussed with reference to incentive accounts of reinforcement and the action of reinforcement on the response units generated by the operative contingencies.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.49-75