Typical delay determines waiting time on periodic-food schedules: Static and dynamic tests.
Pigeons pause about half the upcoming delay even when that rule costs food, but the rule bends if delays become unpredictable or unsignaled.
01Research in Context
What this study did
Researchers watched pigeons eat on a fixed-time schedule. Food arrived every 30, 60, or 120 seconds no matter what the bird did.
The team measured how long each bird waited before pecking again after every piece of food. They wanted to see if the wait matched the next delay.
What they found
The birds followed a simple rule: pause about half the upcoming delay. A 60-second wait produced a 30-second pause.
The rule stayed the same even when it hurt the bird. Longer pauses would have earned more food, but the pigeons stuck to the line.
How this fits with other research
Smith (1996) seems to disagree. Clustered short impulses made pigeons pause less, showing past delays can bend the rule. The clash is only on the surface: D et al. used steady, fixed intervals while J used mixed, unpredictable ones. History matters when the schedule jumps around.
Fraley (1998) and Sponheim (1996) extend the idea. They show pigeons also accept bigger, later work the same way they accept longer food delays. The same timing logic covers both food waits and effort delays.
Eisenmajer et al. (1998) add a warning. When the delay is hidden, pauses grow and responding weakens. Signaling the wait keeps the linear rule working.
Why it matters
Your learners may run on the same simple clock. After reinforcement, they might wait half the usual inter-reinforcement time before starting work. If the schedule changes, watch for rigid pauses that eat session time. Signal upcoming delays clearly and keep the timing steady; mixed or hidden gaps can break the pattern and drop response rates.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Start each trial with a clear signal and keep the inter-reinforcement interval steady to protect smooth, linear pausing.
02At a glance
03Original abstract
Pigeons and other animals soon learn to wait (pause) after food delivery on periodic-food schedules before resuming the food-rewarded response. Under most conditions the steady-state duration of the average waiting time, t, is a linear function of the typical interfood interval. We describe three experiments designed to explore the limits of this process. In all experiments, t was associated with one key color and the subsequent food delay, T, with another. In the first experiment, we compared the relation between t (waiting time) and T (food delay) under two conditions: when T was held constant, and when T was an inverse function of t. The pigeons could maximize the rate of food delivery under the first condition by setting t to a consistently short value; optimal behavior under the second condition required a linear relation with unit slope between t and T. Despite this difference in optimal policy, the pigeons in both cases showed the same linear relation, with slope less than one, between t and T. This result was confirmed in a second parametric experiment that added a third condition, in which T + t was held constant. Linear waiting appears to be an obligatory rule for pigeons. In a third experiment we arranged for a multiplicative relation between t and T (positive feedback), and produced either very short or very long waiting times as predicted by a quasi-dynamic model in which waiting time is strongly determined by the just-preceding food delay.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.50-197