Economic and biological influences on a pigeon's key peck.
Free reinforcers and session length can warp response rates unless you lock the contingency first.
01Research in Context
What this study did
Green et al. (1975) worked with pigeons in a lab chamber.
The birds could peck a key for food.
Sometimes extra grain arrived no matter what.
Sometimes the same grain only came after a peck.
The team changed how long each condition stayed on.
They counted key pecks to see how duration and free food mattered.
What they found
When grain was free, short periods gave many pecks and long periods gave few.
When the same grain required a peck, rates shot up.
The short-long pattern vanished.
Contingency, not just time, steered the birds.
How this fits with other research
Green et al. (2003) repeated the setup and added a treadle.
Key pecking still rose with any extra food, but treadle pressing only rose when food was tied to the step.
The 2003 study extends the 1975 finding: biology plus contingency decides which response grows.
Kendall (1974) ran a similar duration test one year earlier.
That paper showed long stimuli before free food can cut high rates.
Together the trio shows the same lever—duration—can raise or lower behavior depending on what the bird must do to eat.
Why it matters
Your client’s world is full of “free food”: praise, snacks, screen time that just appears.
If the reinforcer is not tied to a target response, you may see odd swings in motivation when activities run long.
Check the contingency first, then the clock.
Tighten the response-reinforcer link and you can flatten those swings without chasing session length.
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02At a glance
03Original abstract
Pigeons were studied in a two-component multiple schedule. In the first phase of the experiment, key pecks were reinforced on a variable-interval 2-min schedule in both components and free food was delivered additionally during one component. When components alternated every 8 sec, all pigeons pecked at a much higher rate during the component with free food than during the other component. At a component duration of 16 min, the reverse was true: all pigeons pecked at a higher rate during the component without free food. In the second phase, the additional food during one component was made contingent on pecking. Responding during the component without the extra food remained essentially unchanged, as expected, since rate of reinforcement remained identical to that in the previous phase. However, rate of responding during the component with the extra food (now contingent on pecking) was elevated, compared to the rate in the first phase, and did not show the marked decline as component duration was increased.
Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.23-55