The role of contingencies and "principles of behavioral variation" in pigeons' pecking.
Contingent reinforcement still drives both faster responding and distinct temporal patterns in pigeons.
01Research in Context
What this study did
Byrd (1980) worked with pigeons in a lab. The birds pecked a small key for grain.
Some birds got grain only after they pecked. Others got grain on a fixed timer, no peck needed.
The team then swapped the schedules and watched how peck speed and timing changed.
What they found
When pecks had to happen to get grain, birds pecked faster. Non-contingent grain slowed them down.
Different schedules also carved out unique peck rhythms. Fixed-interval schedules created a pause-then-burst pattern. Variable schedules spread pecks more evenly.
How this fits with other research
Dews (1978) saw local contrast: peck rate jumped in one key when grain odds rose in a second key. Byrd (1980) adds that the very timing of pecks, not just their rate, bends with contingency.
Cicerone (1976) showed that short 30-s components let overall grain odds rule, while long 3-min parts let local cues take over. Byrd (1980) extends this idea by proving contingencies also sculpt the micro-pattern of each peck burst.
Catania (2021) doubts that reinforcing one response detail boosts that detail on the very next trial. Byrd (1980) does not clash: it tracks molar patterns across many trials, not trial-to-trial copying.
Why it matters
Your client’s response shape is data. If you want steadier work, tie every reinforcer to the target act and use a variable schedule. If you want a pause-then-surge rhythm, switch to fixed-interval. The study reminds us that non-contingent praise or snacks can quietly slow skill-building. Check your delivery system: make sure the learner’s response truly produces the reinforcer.
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02At a glance
03Original abstract
Staddon and Simmelhag's proposal that behavior is produced by "principles of behavioral variation" instead of contingencies of reinforcement was tested in two experiments. In the first experiment pigeons were exposed to either a fixed-interval schedule of response-contingent reinforcement, an autoshaping schedule of stimulus-contingent reinforcement, or a fixed-time schedule of noncontingent reinforcement. Pigeons exposed to contingent reinforcement came to peck more rapidly than those exposed to noncontingent reinforcement. Staddon and Simmelhag's "principles of behavioral variation" included the proposal that patterns (interim and terminal) were a function of momentary probability of reinforcement. In the second experiment pigeons were exposed to either a fixed-time or a random-time schedule of noncontingent reinforcement. Pecking showed a constant frequency of occurrence over postfood time on the random-time schedule. Most behavior showed patterns on the fixed-time schedule that differed in overall shape (i.e., interim versus terminal) from those shown on the random-time schedule. It was concluded that both the momentary probability of reinforcement and postfood time can affect patterning.
Journal of the experimental analysis of behavior, 1980 · doi:10.1901/jeab.1980.34-1