Development of complex, stereotyped behavior in pigeons.
Reinforcement alone can trap learners in one rigid pattern even when many options win.
01Research in Context
What this study did
Twelve pigeons pecked a three-by-three wall of lights. Any eight-peck sequence that ended on the bottom-right light earned food.
Many sequences worked, but only one sequence paid off. The birds had equal paths to reinforcement.
What they found
Every pigeon locked into one rigid eight-peck path. They pecked the same lights in the same order every time.
When food stopped, the birds tried new routes. When the lights went dark, the old pattern fell apart.
How this fits with other research
Morse et al. (1966) showed that turning off food makes pigeons aggressive. Schwartz (1980) adds that extinction also unlocks new responses.
Baer (1974) later used massed extinction to sharpen stimulus control. Together, the three papers show extinction can both break and build patterns.
Van Houten et al. (1980), published the same year, shaped key-peck duration with simple differential reinforcement. B proves that complex spatial chains can be molded just as tightly.
Why it matters
Your client may lock into one rigid route even when many choices pay off. Watch for stereotypy in token boards, response chains, or walking paths. Build extinction probes into your program to keep behavior flexible and to test whether the skill survives new contexts.
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02At a glance
03Original abstract
A pigeon's peck on one key moved a light down one position in a 5x5 matrix of lights, while a peck on another key moved the light across one position. Reinforcement depended upon the occurrence of four pecks on each key (moving the matrix light from the top left to the bottom right), and a fifth peck on either key ended a trial without food. Though there were 70 different sequences that led to reinforcement, each of 12 pigeons developed a particular, stereotyped sequence which dominated its behavior (Experiment 1). Extinction produced substantial increases in sequence variability (Experiment 2). Removal of the matrix cues disrupted performance, though it partially recovered with extended training (Experiment 3). The pigeons did not master a contingency which required a different sequence on the current trial than on the previous one (Experiment 4), though they were able to learn to emit sequences which began with either left-left or left-right response patterns (Experiment 5). The experiments suggest that contingencies of reinforcement may contribute to the creation of complex units of behavior, and that stereotypy may be a likely consequence of contingent reinforcement.
Journal of the experimental analysis of behavior, 1980 · doi:10.1901/jeab.1980.33-153