Effects of search cost on foraging and feeding: a three-component chain analysis.
Pigeons treat long tasks like smart supply chains, not like single drills.
01Research in Context
What this study did
Spangler et al. (1984) built a three-link chain for pigeons. The birds pecked to search, then to procure, then to handle food.
They raised the search cost by making the first link longer. The goal was to see if the birds would still get the same amount of food with fewer total pecks.
What they found
The pigeons kept eating the same daily amount. They did it by picking the low-cost prey and cutting wasted pecks.
When search cost rose, they adjusted the whole chain instead of just working harder on one link.
How this fits with other research
Davis et al. (1994) used the same foraging set-up but added choice. Their pigeons also picked the path that saved time, showing the chain idea holds when birds can switch.
Cryan et al. (1996) saw the opposite: when bar-press cost rose, rats ate less. The birds in F’s study kept intake flat by redesigning the chain, while the rats simply quit early. The difference is the species and the task; birds could reshuffle steps, rats could not.
Neef et al. (1986) looked at the same three-link chain but asked how each stimulus controls pecking. Together the papers show both the efficiency side (F) and the stimulus-control side (A) of chained schedules.
Why it matters
You can teach clients to treat long tasks like chains. If one step gets harder, shift effort to easier steps instead of drilling the hard one. For example, if a child stalls on tooth-brushing (search), let him pick a fun toothbrush (procure) and end with a quick song (handle) so the whole routine still finishes with less fuss.
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02At a glance
03Original abstract
An experiment determined whether pigeons minimize number of key pecks per food delivery and maintain their baseline intake of food while key pecking on a three-component chain schedule. Pigeons at either 80% or 100% body weight obtained all their food during baseline and contingency sessions. During baseline sessions, pecks on the left and center keys had no consequences; each peck on the right key activated the feeder. During contingency sessions, pigeons key pecked on a three-component chain schedule simulating components of a foraging chain. In the search component either 3, 9 or 15 key pecks (varied parametrically across blocks of sessions) on the left key produced a stimulus on the middle key, indicating an encounter with either the low-cost prey (3 key pecks) or an equally probable high-cost prey (21 key pecks). In the procurement component the pigeon pecked either: (a) the left key once, thus returning to the search component, or (b) the middle key either 3 or 21 times, which activated the right response key. In the handling component one peck on the right key operated the feeder. The pigeons always procured the low-cost prey and minimized the number of key pecks per hopper by procuring the high-cost prey when the search-cost ratio was high (15 key pecks) but not when it was low (3 key pecks). All pigeons maintained their baselines of eating during contingency sessions by key pecking more frequently and eating more efficiently. The 80% body-weight birds produced higher overall rates of key pecking and eating. These results have implications for ecological theories of optimal foraging and for psychological theories of learned performance.
Journal of the experimental analysis of behavior, 1984 · doi:10.1901/jeab.1984.42-211