Response-reinforcer independence and the economic continuum: A preliminary analysis.
Free reinforcers act like outside income—cut them and operant work rises along an economic curve.
01Research in Context
What this study did
Pigeons pecked a key for food on a variable-interval schedule.
The twist: extra food also dropped into the hopper for free, but at three different rates.
The author counted how often the birds pecked as the free-food rate changed.
What they found
When free food was plentiful, the birds pecked less.
When free food became scarce, pecking jumped back up.
The results lined up with an economic continuum: work rises as outside income falls.
How this fits with other research
Lattal (1974) showed the same drop in work when any free food enters the chamber.
The 1993 paper reframes that old finding as a smooth economic curve instead of a simple on-off switch.
Dougan (1992) had already shown that less reinforcer supply makes animals work harder per bite.
Coe et al. (1997) later added that the timing of free food and its signal also matter, explaining why some later studies see mixed effects.
Why it matters
If you run NCR or give free access to reinforcers, expect the operant you want to dip.
To keep responding strong, thin the free stuff first, then stretch the schedule.
Think of reinforcement like a budget: more outside income means less need to work.
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02At a glance
03Original abstract
Three pigeons were exposed to 1-hr and 4-hr sessions during which they earned food under a fixed-ratio 50 schedule of reinforcement while obtaining additional food according to either a variable-interval or a variable-time schedule. Postsession food was provided after the 1-hr sessions. The frequency of the variable-interval and variable-time food presentations was varied under the two session durations. The various combinations of within-session earned and unearned food, as well as the postsession food, defined conditions on the open-to-closed economy continuum. Key pecks tended to increase as the frequency of either variable-interval or variable-time food decreased. An economic-continuum analysis based on an independence quotient as a measure of response-reinforcer independence is presented to account for the effects.
Journal of the experimental analysis of behavior, 1993 · doi:10.1901/jeab.1993.59-231