Concurrent variable-ratio schedules: Implications for the generalized matching law.
Rats follow the matching law under concurrent VR schedules only when each response advances both counters; otherwise they exclusively pick the richer option.
01Research in Context
What this study did
The team placed rats in a chamber with two levers.
Each lever paid off on a variable-ratio (VR) schedule.
The twist: sometimes a press on one lever also added a count toward the other lever’s requirement.
They wanted to know if the matching law still predicts choice when the two schedules are linked this way.
What they found
When both counters went up together, the rats split their time close to the payoff rates.
When only the active lever advanced its own counter, the animals almost always picked the richer side.
In short, dependence made matching; independence made exclusivity.
How this fits with other research
Lejuez et al. (2001) later saw matching with wheel-running on concurrent VI schedules, showing the rule holds across very different reinforcers and schedule types.
Bromley et al. (1998) moved the idea to humans, finding that children and adults with disabilities also shift choice when payoff rates change, proving the lab result stretches to clinical populations.
Atnip (1977) had warned that matching equations for simple ratio schedules predict odd pauses that data do not show; the 1988 study answers that critique by testing ratios in a concurrent set-up and finding orderly choice under the right counter rule.
Why it matters
Your clients often face “concurrent schedules” — stay at the desk for tokens or go to the tablet for free videos.
If both behaviors earn credit at the same time (think token board ticking while they also scroll), the matching law says they will divide time roughly by payoff rate.
If only the active behavior earns credit, expect them to lock onto the richer side.
Set up your reinforcement systems so the desired behavior gets its counter advanced even when the client is engaged elsewhere; you will see more balanced choice instead of all-or-none preference.
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02At a glance
03Original abstract
Rats' responses were reinforced on concurrent variable-ratio variable-ratio schedules in which responses on one lever incremented the ratio counter and responses on a second lever changed the schedule and correlated stimulus. The relative frequency of reinforcement was varied from .10 to .99. In one set of conditions, responding on the main lever incremented both ratio counters, but reinforcement required a response in the presence of the stimulus correlated with the ratio that had been completed. In a second set of conditions, responses on the main lever incremented only the ratio correlated with the stimulus that was currently present. When main-lever responses incremented both ratio counters, subjects distributed responding and time in a manner consistent with the generalized matching law. When responses on the main lever incremented only the schedule currently in effect, the rats responded almost exclusively on the schedule producing the higher frequency of reinforcement. These results extend the applicability of the generalized matching law to dependent ratio schedules.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.50-55