Concurrent-schedule performance: Effects of relative and overall reinforcer rate.
Lean schedules dull sensitivity to payoff ratios, so clients stop favoring the better option.
01Research in Context
What this study did
The team set up two VI schedules side by side. Pigeons could hop between keys, but a 2-second delay stopped rapid switching.
They held the ratio of reinforcers steady while dropping the total rate. The goal was to see if the birds still matched their responses to the payoff ratio when the overall haul shrank.
What they found
When the overall reinforcer rate fell, the birds’ response ratio drifted away from the payoff ratio. In plain words, they stopped tracking which key paid better.
Sensitivity to the reinforcer ratio weakened as the session got leaner.
How this fits with other research
Costa et al. (2025) later showed the flip side: lower overall rate actually boosts resistance to change in adult humans. Same variable, different outcome—rate cuts both sensitivity and persistence.
Lowe et al. (1995) used water instead of food and saw similar within-session curves, hinting the reinforcer type does not erase the pattern B et al. found.
Duker et al. (1996) added that visual cues can protect responding under disruption. Together the papers say: reinforcer rate sets the baseline, but modality and contingency fine-tune how tough that behavior is.
Why it matters
If you thin a token board or stretch the schedule, do not expect perfect matching. Clients may act as if the richer side no longer matters. Check the total rate first, then adjust ratio or add salient cues to keep choice accurate.
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02At a glance
03Original abstract
Six pigeons were trained to respond on two keys, each of which provided reinforcers on an arithmetic variable-interval schedule. These concurrent schedules ran nonindependently with a 2-s changeover delay. Six sets of conditions were conducted. Within each set of conditions the ratio of reinforcers available on the two alternatives was varied, but the arranged overall reinforcer rate remained constant. Each set of conditions used a different overall reinforcer rate, ranging from 0.22 reinforcers per minute to 10 reinforcers per minute. The generalized matching law fit the data from each set of conditions, but sensitivity to reinforcer frequency (a) decreased as the overall reinforcer rate decreased for both time allocation and response allocation based analyses of the data. Overall response rates did not vary with changes in relative reinforcer rate, but decreased with decreases in overall reinforcer rate. Changeover rates varied as a function of both relative and overall reinforcer rates. However, as explanations based on changeover rate seem unable to deal with the changes in generalized matching sensitivity, discrimination accounts of choice may offer a more promising interpretation.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.49-21