Alternative fixed-ratio fixed-interval schedules of reinforcement.
Bigger fixed-ratio requirements slow responding and stretch pauses, so keep early ratio boards small to maintain momentum.
01Research in Context
What this study did
Rider (1980) looked at how animals act when two schedules run at once. One schedule pays after a set number of presses (FR). The other pays after a set time (FI).
The team slowly raised the number of presses needed. They watched how fast the animal worked and how long it paused after each reward.
What they found
When the press requirement grew, the animal slowed down. It also waited longer after each reward before starting again.
At high press numbers the record showed a clear break-and-run shape: a long pause, then a quick burst of presses.
How this fits with other research
Sanders (1969) ran the same two-schedule setup with college students. People also slowed the FI side when the FR side was small, but they did not show the long pauses seen in animals. The animal pattern holds across species, yet the pause may vanish in humans.
Crossman et al. (1985) tested very small ratios (FR 1 to FR 7) and saw the opposite pause effect: pauses got shorter as the ratio rose. This sounds like a contradiction, but it marks a boundary. The lengthening pause only appears once the ratio moves past the single-digit range.
Abrahamsen et al. (1990) later used tandem FI-FR schedules and found the same drop in rate when the added ratio cut the overall payoff. The 1980 data still stand; they just remind us to watch how often reinforcement actually occurs.
Why it matters
If you use a token board or piece-rate system, think of it as a small FR sitting inside a larger FI. Start with low ratios to avoid long pauses or ratio strain. If you see a learner stall after each payout, shrink the ratio or add prompts right after delivery. The break-and-run pattern is normal, but only when the ratio is big enough to matter.
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02At a glance
03Original abstract
Five rats were trained under alternative fixed-ratio fixed-interval schedules, in which food reinforcement was provided for the completion of either a fixed-ratio or a fixed-interval requirement, whichever was met first. Overall response rate and running rate (the rate of responding after the postreinforcement pause) decreased for all subjects as the fixed-ratio value increased. As the proportion of reinforcements obtained from the fixed-ratio component increased and the alternative schedule approached a simple fixed ratio, overall response rate and running rate both increased; conversely, as the proportion of reinforcements obtained from the fixed-interval component increased and the alternative schedule approached a simple fixed interval, response rates decreased. Postreinforcement pause length increased linearly as the average time between reinforcements increased, regardless of the schedule parameters. A break-run pattern of responding was predominant at low- and medium-valued fixed ratios. All subjects displayed at least occasional positively accelerated responding within interreinforcement intervals at higher fixed-ratio values.
Journal of the experimental analysis of behavior, 1980 · doi:10.1901/jeab.1980.33-243