Molar And Molecular Control In Variable-interval And Variable-ratio Schedules.
Interval schedules keep response rates low because they reinforce pauses—choose ratio schedules when you need high, steady response speed.
01Research in Context
What this study did
The team compared three reinforcement schedules head-to-head. They used a standard variable-ratio schedule, a standard variable-interval schedule, and a special variable-interval schedule that paid more often when the participant responded faster.
All testing happened in a lab with single-case methods. The goal was to see if interval schedules keep response rates low because they reward long pauses.
What they found
Even when the interval schedule was rigged to pay for fast responding, rates stayed lower than on the ratio schedule. The built-in reward for long pauses, not feedback, drives the VI-VR gap.
How this fits with other research
Baum (2025) builds on this result with a matching-law model. It shows ratio schedules collapse at lean pay rates because their molar unit is smaller, not because of tiny timing gaps.
Jones et al. (2024) moves the same VI-vs-VR contrast into punishment tests with rats. Interval schedules created habit-like responding that kept going even when cocaine trials hurt.
Dardano (1972) used a similar single-case lab set-up. It found lick rate tracked pay rate across schedule parts, backing the idea that reinforcement timing controls behavior output.
Why it matters
When you need rapid, steady responding, pick ratio schedules. Interval schedules will always reward some long pauses, so they cap how fast behavior can get. Use this fact when shaping fluent skills or building endurance.
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02At a glance
03Original abstract
Response rates are typically higher under variable‐ratio than under variable‐interval schedules of reinforcement, perhaps because of differences in the dependence of reinforcement rate on response rate or because of differences in the reinforcement of long interresponse times. A variable‐interval‐with‐added‐linear‐feedback schedule is a variable‐interval schedule that provides a response rate/reinforcement rate correlation by permitting the minimum interfood interval to decrease with rapid responding. Four rats were exposed to variable‐ratio 15, 30, and 60 food reinforcement schedules, variable‐interval 15‐, 30‐, and 60‐s food reinforcement schedules, and two versions of variable‐interval‐with‐added‐linear‐feedback 15‐, 30‐, and 60‐s food reinforcement schedules. Response rates on the variable‐interval‐with‐added‐linear‐feedback schedule were similar to those on the variable‐interval schedule; all three schedules led to lower response rates than those on the variable‐ratio schedules, especially when the schedule values were 30. Also, reinforced interresponse times on the variable‐interval‐with‐added‐linear‐feedback schedule were similar to those on variable interval and much longer than those produced by variable ratio. The results were interpreted as supporting the hypothesis that response rates on variable‐interval schedules in rats are lower than those on comparable variable‐ratio schedules, primarily because the former schedules reinforce long interresponse times.
Journal of the experimental analysis of behavior, 1999 · doi:10.1901/jeab.1999.71-319