Some effects of response-dependent clock stimuli in a fixed-interval schedule.
A brief clock light after each response lengthened the post-food pause and cut overall pecking in pigeons on an FI schedule.
01Research in Context
What this study did
Pigeons pecked a key for food on a fixed-interval 3-min schedule.
Each peck after the interval reset a small clock light for 0.2 s.
The same birds later worked without the clock light.
The team compared response rate and pause length across the two setups.
What they found
When the clock light came on, birds pecked less often.
Their pause after food grew longer.
Without the clock, rates returned to normal.
The extra cue seemed to slow the birds down, not speed them up.
How this fits with other research
Fantino (1969) first mapped how pauses stretch or shrink across different FI lengths.
Arnett (1972) shows that adding a simple clock cue can stretch the pause even when the FI stays the same.
Hassin-Herman et al. (1992) later swapped FI lengths day-to-day and found birds wait longer after short intervals.
Together, the three studies show pauses are plastic: they bend with both interval length and visible cues.
Davison et al. (1991) looks like a contradiction at first glance.
They saw low rates after a history of long inter-response times, while Arnett (1972) got low rates from a tiny clock light.
The difference is the cause: one is learning history, the other is a momentary cue.
Both warn us that low responding can come from very different sources.
Why it matters
If you run FI-based programs, know that extra lights, sounds, or timers can quiet behavior instead of cue it.
Test any new stimulus for a few sessions and graph the rate.
If responding drops, drop the cue or reshape it into a signal for faster work.
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02At a glance
03Original abstract
Two experiments studied the effects of brief response-dependent clock stimuli in fixed-interval schedules of reinforcement. In the first experiment, two pigeons were exposed to a fixed-interval schedule. Two conditions were compared. In both conditions each peck on the key produced a brief stimulus. In one condition, pecks produced a different stimulus in successive sixths of the interval. This was the clock condition. In the other condition, the same stimulus was produced throughout the interval. Response rates were lower and the pause after reinforcement was longer in the clock condition. In the second experiment, a two-key optional clock procedure was used. Responding on the clock key produced one of three stimuli correlated with the three successive minutes of a fixed-interval schedule. A response on the other key produced grain at the end of the 3 min. When the final stimulus was removed from the situation and pecking produced nothing during the third minute, responding to the clock key declined to a very low rate. When the first two stimuli were removed and the third one replaced, responding to the clock key was resumed.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.17-161