The operant conditioning of response variability: Free-operant versus discrete-response procedures.
Brief timeouts after each response create variety; free-operant setups create repetition.
01Research in Context
What this study did
Pigeons pecked four times on a panel.
The birds had to make a different four-peck order each time to earn food.
One group worked in short trials with a brief blackout after every response.
A second group pecked freely with no breaks.
The study asked which setup gives more varied pecking and more food.
What they found
The trial-plus-timeout birds earned three times more food.
They also kept making new four-peck patterns.
The free-peck birds fell into the same pattern again and again.
They missed most chances for food because their responses were too similar.
How this fits with other research
Hamm et al. (1978) saw the same split with location pecks: fixed-interval schedules made varied spots, fixed-ratio made rigid spots.
The 1987 study shows the split again, but now with short timeouts doing the work of an interval.
Attwood et al. (1988) later showed the danger in people: longer fixed-interval schedules for adaptive behavior raised stereotypy in adults with ID.
Together the papers warn that loose, free-running schedules can lock in repetition, whether in birds or humans.
Why it matters
If you want flexible responding, give brief timeouts after each response.
Use clear trials instead of letting the client respond nonstop.
This simple switch keeps reinforcement high and stereotypy low.
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Insert a two-second pause after each response when teaching a new play sequence.
02At a glance
03Original abstract
The operant conditioning of response variability under free-operant and discrete-response procedures was investigated. Two pigeons received food only if their pattern of four pecks on two response keys differed from the patterns emitted on the two immediately preceding trials. Under the free-operant procedure, the keys remained illuminated and operative throughout each trial. There was little variability in the response patterns that resulted, and the pigeons received fewer than one third of the available reinforcers. Under the discrete-response procedure, a brief timeout period followed each response. Variability increased under this procedure, and the pigeons obtained three fourths of the available reinforcers. Previous successes and failures to produce response variability may have been due to the use or failure to use, respectively, a discrete-response procedure. Respondent effects inherent in the free-operant procedure may encourage the development of response stereotypy and, in turn, prevent the development of response variability.
Journal of the experimental analysis of behavior, 1987 · doi:10.1901/jeab.1987.47-273