Varying wheel-running reinforcer duration within a session: effect on the revolution-postreinforcement pause relation.
Tired muscles barely lengthen the post-reinforcement pause; reinforcer value matters more.
01Research in Context
What this study did
Scientists let rats run in a wheel for food. They changed how long each run lasted within the same session.
They watched how long the rats paused after each run before they started working again.
What they found
Longer runs made the pause only a little longer. Most of the pause time stayed the same.
The link between run length and pause was weak. Most pauses did not follow a clear pattern.
How this fits with other research
Fisher et al. (2003) later showed that when rats could choose between sweet water and wheel time, longer wheel runs or weaker sweet water both made pauses grow. Their effect was bigger and clearer.
Glover et al. (1976) and Bachman et al. (1988) had already shown that richer food makes pauses longer on ratio schedules. The 2000 wheel study adds that, inside one session, simply tiring the legs is not enough to drive the pause.
Together the papers say: pause length cares more about how good the reinforcer feels than about how tired the body gets.
Why it matters
When you shape behavior, do not assume fatigue drives long pauses. Check the value of the reinforcer first. If a child stalls after a big response, try lowering the work requirement or boosting the payoff before you blame tiredness.
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02At a glance
03Original abstract
Previous investigations of wheel-running reinforcement that manipulated reinforcer duration across conditions showed a strong relation between wheel-running rate and average postreinforcement pause (PRP) duration. To determine if the basis of this relation across conditions was a local effect of fatigue or satiation, the correlation between revolutions run and the duration of the immediately following PRP was investigated under conditions in which reinforcer duration was either constant or variable within a session. Seven male Wistar rats pressed a lever on a fixed-interval 60-s reinforcement schedule with the opportunity to run for 60 s as the reinforcing consequence. In the constant-duration condition, the duration of the reinforcer was always 60 s. In the variable-duration condition, the duration of the reinforcer varied between 2 and 240 s with a mean of 60 s. Mean correlations between revolutions run and the next PRP duration for constant, variable, and constant conditions were -.07, .20, and -.07, respectively. Although the positive correlation in the variable-duration condition is consistent with an effect of momentary fatigue or satiation, little of the variance in PRP duration appears to be attributable to these factors.
Journal of the experimental analysis of behavior, 2000 · doi:10.1901/jeab.2000.73-225