Key pecking under response-independent food presentation after long simple and compound stimuli.
Auto-shaping creates fast, sturdy key pecks in pigeons and the timing of the signal controls how soon and how hard the bird responds.
01Research in Context
What this study did
The team used auto-shaping with pigeons. A light came on, then food arrived no matter what the bird did.
They tried two tricks. Some trials used a short light, others a long light. A few trials paired the light with a tone.
They watched when each bird first pecked the key and how fast it pecked during the light.
What they found
Every pigeon learned to peck. Shorter lights made the first peck happen sooner.
When light and tone played together, the birds pecked faster and faster as the signal stayed on.
How this fits with other research
Locurto et al. (1980) held the birds still during the first trials. Their pigeons also pecked sooner, showing that early restraint speeds auto-shaping.
Wilkie et al. (1981) trimmed the birds' beaks so they could not eat normally. The birds still pecked the key, proving the movement is not just a mis-aimed bite.
Mulvaney et al. (1974) later tested monkeys with the same method. The monkeys pecked at first but stopped when pecking cancelled food, a hint that species matter.
Why it matters
Auto-shaping gives you a quick, reliable first response. Use brief signals if you want faster take-off and pair signals if you want rising momentum. Remember that even severe physical changes—like restraint or trimmed beaks—do not stop the response, so do not worry if a client has motor limits. Watch for species or individual differences when you fade contingencies; what sticks in pigeons may vanish in primates.
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02At a glance
03Original abstract
Sixteen pigeons were trained to peck a key using a response-independent (auto-shaping) procedure of food presentation. The 4-sec grain presentations were independent of responding but a keylight stimulus preceded each, with a 4-min interval between the grain presentation and the next stimulus. Subjects were divided into four groups, with two durations of the keylight (30 or 120 sec) and either one or four successive colors on the response key preceding food delivery. In Phase 2, the birds were continued with the same keylight duration but were presented the alternative number of key colors. All pigeons pecked the key during the stimulus. Birds in the two groups with the 30-sec stimulus duration began to respond significantly sooner than birds with the 120-sec duration. There were no significant differences in rate of pecking between groups by the last five days of Phase 1. In Phase 1, the pigeons exposed to the four stimulus components showed an increase in rate of pecking over the four components as grain presentation approached. The pigeons with one stimulus component did not exhibit this regularity. Analogous conditions in Phase 2 had similar results except for one group. The implications of the occurrence of key pecking due to response-independent food delivery for multiple and chained schedules were pointed out.
Journal of the experimental analysis of behavior, 1973 · doi:10.1901/jeab.1973.19-509