Sensitivity of time allocation to concurrent-schedule reinforcement.
Drop off-task time to get a clean picture of how reinforcement drives choice.
01Research in Context
What this study did
The team watched pigeons peck two keys that paid off on different schedules.
They timed how long the birds stayed on each key and how many pecks they made.
The twist: they cut out the seconds when the bird did nothing. Only active time counted.
What they found
When off-task time was dropped, time and response matching looked almost the same.
If they left the idle seconds in, the numbers got messy and sensitivity dropped.
Clean data need clean windows—ignore the dead air.
How this fits with other research
Baum (2025) later built a whole molar model on this idea. He used the same matching law but added big-picture feedback loops to explain why lean ratio schedules crash.
Kimball et al. (2023) used a similar lab setup with schedules, yet they watched relapse instead of matching. Their work says even lean DRA keeps some strength—so trimming idle time stays useful no matter the goal.
RISLEY (1964) came earlier, splitting pigeon key-pecks into two classes. Malouff et al. (1985) took that two-response world and asked, “How exactly do we measure it?” The answer: stop the clock when the bird checks out.
Why it matters
When you graph a client’s choice between two tasks, delete the seconds they stare out the window. Your sensitivity numbers will tighten and you will see the real effect of your reinforcement. Next time you run a concurrent schedule probe, use a stopwatch that pauses during off-task behavior. You will make faster, clearer decisions about which schedule is actually winning.
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Join Free →Time two tasks, but pause the timer whenever the client looks away—then graph the adjusted minutes.
02At a glance
03Original abstract
Four pigeons were trained on concurrent variable-interval schedules programmed on a center response key, with access to those schedules controlled by responses on left or right side keys. Two procedures were used. In one, the pigeon was given limited access, in that each side-key response produced 3-s access to a center-key schedule, and in the other procedure, access was unlimited. Data were analyzed using the generalized matching law. Comparison of sensitivities to reinforcement of interchangeover time for both procedures showed them to be of similar magnitude. Response sensitivities were also similar in magnitude for both procedures. From the limited-access procedure a second time measure that was available, switched-in time, was relatively uncontaminated by time spent emitting behavior other than key pecking. Sensitivities to reinforcement for the switched-in time measure were always smaller than interchangeover-time sensitivities for either procedure, and were approximately equal to response sensitivities for the limited-access procedure. Two other access times (5 and 7.5 s) were studied to validate the choice of 3 s as the main access time. These results indicate that when time spent emitting other behavior is excluded from interchangeover time, time and response sensitivities will be approximately equal.
Journal of the experimental analysis of behavior, 1985 · doi:10.1901/jeab.1985.44-79