Choice, foraging, and reinforcer duration.
Pigeons pick quick small payoffs over delayed big ones unless both sides are equally delayed and clearly signaled.
01Research in Context
What this study did
Researchers let pigeons peck two keys. One key led to short handling time and a small food hopper. The other key led to longer handling time and a bigger hopper.
They changed how long the birds had to "search" before each option appeared. Then they watched which key the pigeons picked.
What they found
When search time grew, pigeons took the small, quick reinforcer more often. Their choices followed the delay-reduction rule: shorter wait equals better deal.
The results matched both delay-reduction math and optimal-diet models from biology.
How this fits with other research
Aman et al. (1987) ran a near-copy study the next year. They added equal delays to both choices and saw the same flip toward the longer reinforcer. The two papers fit like puzzle pieces; together they show duration matters most when both sides are delayed.
Eisenmajer et al. (1998) seems to disagree. A surprise 3-s delay hurt responding in three of four pigeons. The key difference is signaling: Emmelkamp et al. (1986) always lit the keys during the wait, while R et al. left the delay unsignaled. Signal the wait and duration stays useful; hide the wait and value crashes.
Reed et al. (1988) moved the task to teens with intellectual disability. The humans showed the same reversal as the pigeons: long delays pushed them toward smaller-sooner rewards. The animal rule travels to people.
Why it matters
If a client stalls before a big reinforcer, shorten the visible wait or add a clear signal. Break a 10-minute delay into two 5-minute stages with tokens or lights. The pigeon data says the perceived wait, not the clock time, drives the choice.
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02At a glance
03Original abstract
Pigeons were exposed to a foraging schedule characterized by three different states, beginning with a search state in which completion of a variable interval on a white key led to a choice state. In the choice state the subject could, by appropriate responding on a fixed ratio of three, either accept or reject the schedule offered. If the subject accepted the schedule, it entered a handling state in which the appropriate reinforcer amount was presented according to a variable-interval schedule. In Experiment 1 the shorter duration reinforcer was more likely to be accepted the longer the duration of the search state and the shorter the equal durations of the handling states. In Experiment 2 the shorter duration reinforcer was more likely to be accepted the longer the handling time preceding the longer duration reinforcer. All of the results were in qualitative--and some were in quantitative--agreement with those predicted by the delay-reduction hypothesis and the optimal-diet model.
Journal of the experimental analysis of behavior, 1986 · doi:10.1901/jeab.1986.46-93