Sensitivity of time allocation to an overall reinforcer rate feedback function in concurrent interval schedules.
Overall reinforcer-rate feedback does not control preference on concurrent VI schedules—matching isn’t simple maximizing.
01Research in Context
What this study did
Researchers placed six pigeons in a chamber with two side keys.
Each key paid food on its own variable-interval schedule.
A computer quietly changed the total food rate for both keys together.
The birds never knew this global rate moved; only local key rates mattered.
The team asked: if we raise or lower the overall food rate, will the birds shift their time between keys?
What they found
Time spent on each key stayed the same no matter how the total food rate changed.
Birds kept matching their time to the local key rates, ignoring the extra feedback.
The result cuts against simple “maximize total food” stories of the matching law.
How this fits with other research
Macdonald et al. (1973) first showed pigeons match time to local reinforcement rates.
Davison et al. (1989) now says that effect is blind to overall feedback, so matching is not pure maximization.
Yuwiler et al. (1992) ran a later, similar test and also saw matching beat maximization, supporting the null feedback effect.
Hall (2005) adds another twist: when food is earned at one rate but delivered at another, the basic matching equation breaks.
Together the four papers tell us local contingencies, not global totals, steer choice.
Why it matters
When you set up concurrent reinforcement at home, school, or clinic, focus on the separate rates each alternative delivers.
Changing the total amount of reinforcement while keeping the same proportions will not push your client toward a different choice.
Instead, adjust the relative rate or immediacy of each option if you want to see a shift in time allocation.
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02At a glance
03Original abstract
Six pigeons were trained on concurrent variable-interval schedules in which feedback functions arranged that the overall reinforcer rate either (a) was independent of preference, (b) decreased with increasing absolute preference, or (c) increased with increasing absolute preference. In Experiment 1, the reinforcer rate in an interreinforcement interval was determined by the absolute time-allocation ratio in the previous interval. When arranged reinforcer ratios were varied, there was no evidence of control over preference by overall reinforcer rate. In Experiment 2, the feedback function arranged that reinforcer rates were an inverse function of absolute preference, and window durations were fixed times. In Phase 1, using schedules that provided a four-to-one reinforcer ratio, the window duration was decreased from 20 s to 5 s over four conditions. Then, in Phases 2 and 3, the arranged reinforcer ratios were varied. In Phase 2, the reinforcer rate in the current 5-s time window was determined by preference in the previous 5-s window, and in Phase 3, the window durations were 20 s. Again, there was no indication of control by obtained overall reinforcer rate. These data call into question theories that suggest that the process underlying matching is one of maximizing overall reinforcer rates, or that preference in concurrent aperiodic schedules is controlled to any extent by overall reinforcer rate. They also question the notion that concurrent-schedule preference is controlled by molecular maximizing.
Journal of the experimental analysis of behavior, 1989 · doi:10.1901/jeab.1989.51-215