Food deliveries during the pause on fixed-interval schedules.
Extra food during the pause hardly moves fixed-interval pause length—schedule control wins.
01Research in Context
What this study did
Kodera et al. (1976) worked with pigeons on fixed-interval schedules.
They gave extra food during the post-reinforcement pause.
The team wanted to see if free food would stretch the pause longer.
What they found
Extra food barely changed pause length.
Only when the next interval started with the first peck did pauses grow a little.
Most of the time the FI clock ruled the bird’s timing anyway.
How this fits with other research
Gardner et al. (1977) later showed that brief stimuli can keep the FI pattern even when cocaine, not food, is the payoff.
Their work extends the 1976 finding: schedule structure beats the type of reinforcer.
Falcomata et al. (2012) tracked pause development across 200 sessions and found pause length stabilizes slowly.
That longitudinal view deepens the 1976 result—once pause timing is set, even extra food can’t budge it much.
Fay (1979) restricted rats to one response per cycle and also saw only tiny pause changes.
Together these studies line up: FI temporal control is hard to break.
Why it matters
If you run FI or FI-based token programs, don’t worry about accidental extra reinforcers during the pause.
The schedule clock, not the extra reward, drives the client’s wait time.
Keep your timing rules clear and consistent; the pattern will hold.
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02At a glance
03Original abstract
Pigeons were trained on fixed-interval schedules of food delivery. In Experiments I and II, the fixed interval was initiated by the previous fixed-interval reinforcer; in Experiment III, the fixed interval was initiated by the first key peck following the preceding fixed-interval reinforcer (a chain fixed-ratio one, fixed-interval schedule). During the postreinforcement pause, variable-time schedules delivered food independent of any specific response. Rate of food delivery during the pause had only small effects on pause duration in Experiments I and II. In Experiment III, however, pause duration increased systematically with the rate of food delivery during the pause. These data suggest that the momentary proximity to reinforcement delivered via the fixed-interval schedule exerts potent control over pause termination. Additional analysis revealed that pause termination was unaffected by the intermittent delivery of food during the pause. Such data suggest that the temporal control by fixed-interval schedules is highly resistant to interference.
Journal of the experimental analysis of behavior, 1976 · doi:10.1901/jeab.1976.26-415