Behavioral variability and frequency-dependent selection.
You can reinforce novelty itself, turning even stereotyped pigeons into random-like performers.
01Research in Context
What this study did
Researchers worked with pigeons in a lab. The birds had to peck four times on a key. Some pigeons only got food when their four-peck sequence was new. Other pigeons got food no matter how they pecked. The team watched what happened to the birds' patterns.
What they found
When novelty earned food, the pigeons acted almost random. No two four-peck runs looked the same. When the rule vanished, the birds slipped back into stiff, repeated routines. The schedule itself, not the bird, drove the switch.
How this fits with other research
Byrd (1980) and Julià (1982) already showed that plain contingent reinforcement speeds pecking and molds short run lengths. Hall (1992) goes further: it proves you can reinforce the absence of a pattern, not just the presence of one. Wesp et al. (1981) taught pigeons rigid four-color chains; Hall (1992) flips that idea and breaks the chain, turning four pecks into a stream of novelty. Together the studies show reinforcement can create both tight drill and near-random variation in the same animal.
Why it matters
If you want a client to vary words, play moves, or try new steps, build a payoff for novelty. Start small: reinforce any response that differs from the last three. Watch rigid routines loosen into flexible repertoires. The bird data says variability is not a trait; it is an operant you can strengthen.
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02At a glance
03Original abstract
In Experiment 1, two conditions were compared: (a) a variability schedule in which food reinforcement was delivered for the fourth peck in a sequence that differed from the preceding N four-peck sequences, with the value of N continuously adjusted to maintain reinforcement probability approximately constant; and (b) a control condition in which the variability constraint was dropped but reinforcement probability remained constant. Pigeons responded approximately randomly under the variability schedule but showed strong stereotyped behavior under the control condition. Experiments 2 and 3 tested the idea that variability is the outcome of a type of frequency-dependent selection, namely differential reinforcement of infrequent behavior patterns. The results showed that pigeons alternate when frequency-dependent selection is applied to single pecks because alternation is an easy-to-learn stable pattern that satisfies the frequency-dependent condition. Nevertheless, 2 of 4 pigeons showed random behavior when frequency-dependent selection was applied to two pecks, even though double alternation is a permissible and stable stereotype under these conditions. It appears that random behavior results when pigeons are unable to acquire the stable stereotyped behavior under a given frequency-dependent schedule.
Journal of the experimental analysis of behavior, 1992 · doi:10.1901/jeab.1992.58-241