Steady-state performance on fixed-, mixed-, and random-ratio schedules.
On ratio schedules the speed of continuous responding stays constant; what changes are the pauses, not the burst rate.
01Research in Context
What this study did
Mazur (1983) compared three ratio schedules side-by-side. Rats pressed a lever on fixed-ratio, mixed-ratio, and random-ratio schedules while the team recorded every pause and response burst.
The goal was to see if Mazur's theory held up: do pauses explain most of the differences we see across ratio types?
What they found
All three schedules produced the same fast burst of responses once the run started. The big difference was in the pauses that came right after reinforcement.
Fixed-ratio created the longest post-reinforcement pauses. Mixed and random ratios shortened those pauses, but the burst speed stayed constant. Mazur's idea about pauses was partly right.
How this fits with other research
Mechner (1958) first described the long pause after fixed-ratio reinforcement. Mazur (1983) adds numbers, showing the pause shrinks when the schedule becomes unpredictable.
Barrett et al. (1987) later found the same pause pattern with a continuous lever hold, proving the rule works even when the response is not a discrete press.
Clarke et al. (1998) moved the idea into a classroom token system. They saw fewer stereotypy starts when teens with severe ID earned tokens on fixed-ratio instead of variable-interval, matching the lab pause data.
Together these studies build a line: longer pauses after fixed ratios appear in rats, pigeons, monkeys, and students, and can be used to shape smoother work cycles.
Why it matters
If you want steady work with short breaks, choose variable or mixed ratio schedules. If you need a clear break after each payoff, stay with fixed ratio. Watch the pause, not the speed — that's where the schedule speaks.
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Join Free →Count post-reinforcement pauses during your client's token board task; if breaks are too long, switch to a mixed ratio and time the new pause length.
02At a glance
03Original abstract
Three groups of rats pressed a lever for milk reinforcers on various simple reinforcement schedules (one schedule per condition). In Group M, each pair of conditions included a mixed-ratio schedule and a fixed-ratio schedule with equal average response:reinforcer ratios. On mixed-ratio schedules, reinforcement occurred with equal probability after a small or a large response requirement was met. In Group R, fixed-ratio and random-ratio schedules were compared in each pair of conditions. For all subjects in these two groups, the frequency distributions of interresponse times of less than one second were very similar on all ratio schedules, exhibiting a peak at about .2 seconds. For comparison, subjects in Group V responded on variable-interval schedules, and few interresponse times as short as .2 seconds were recorded. The results suggest that the rate of continuous responding is the same on all ratio schedules, and what varies among ratio schedules is the frequency, location, and duration of pauses. Preratio pauses were longer on fixed-ratio schedules than on mixed-ratio or random-ratio schedules, but there was more within-ratio pausing on mixed-ratio and random-ratio schedules. Across a single trial, the probability of an interruption in responding decreased on fixed-ratio schedules, was roughly constant on random-ratio schedules, and often increased and then decreased on mixed-ratio schedules. These response patterns provided partial support for Mazur's (1982) theory that the probability of instrumental responding is directly related to the probability of reinforcement and the proximity of reinforcement.
Journal of the experimental analysis of behavior, 1983 · doi:10.1901/jeab.1983.39-293