Post-reinforcement pauses and response rate of monkeys on a two-hand fixed-ratio schedule.
Post-reinforcement pause length tracks the overall fixed-ratio requirement, not nearby ratio cues.
01Research in Context
What this study did
Monkeys pressed two levers instead of one to earn food.
The fixed-ratio size changed across sessions.
Researchers timed how long the monkeys paused after each reinforcer.
What they found
Pause length matched the session-wide ratio, not the last or next ratio.
The monkeys’ quick lever taps stayed the same no matter the ratio.
How this fits with other research
Halpern et al. (1966) first showed pigeons pause longer on bigger fixed ratios.
Crossman et al. (1985) later saw the opposite in tiny FR 1-7 schedules.
The pause shrank as the ratio grew, but only because the ratios were very small.
Young et al. (2017) added that upcoming reinforcer size also tweaks pause length.
Feldman et al. (1999) warn averaged data hide the true skewed pause shape.
Why it matters
When you design a fixed-ratio program, remember the overall ratio sets the pause, not local changes.
Check the whole session context before you tweak ratio size.
If you run small ratios, expect shorter pauses, not longer ones.
Plot individual pause times instead of just the mean to see the real pattern.
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02At a glance
03Original abstract
Fixed-ratio behavior of monkeys was analyzed separately for two hands. While one hand responded on the fixed-ratio schedule the other performed a holding response and the function of the hands changed in alternate ratio runs. After performance was stable on the fixed ratio (70 responses, two monkeys; 100 responses, two monkeys, 120 responses, two monkeys) 90 sessions of further training equalized post-reinforcement pauses and the mean interresponse time of the two hands. Hand preference in reaching for food remained unchanged. Then, the fixed-ratio requirement was changed (a) in small sequential steps, (b) in two large steps, and, (c) within sessions alternating two runs at a high ratio with two runs at a low ratio. The mean duration of post-reinforcement pauses was correlated with a fixed ratio maintained throughout a session but single pauses were neither controlled by the immediately preceding nor by the following ratio run when a cue to its length was available. The mean interresponse time was insensitive to changes in fixed ratio. The fixed-ratio performance was generally similar to that of pigeons and rats.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.17-85