Independently delivered food decelerates fixed-ratio rates.
Extra free food barely slows fixed-ratio responding unless you double the rate and wait dozens of sessions.
01Research in Context
What this study did
Edwards et al. (1970) watched pigeons peck a key on a fixed-ratio schedule.
While the birds worked, the team also dropped free food on a timer.
They wanted to see if the extra food would slow the birds down.
What they found
The free food barely touched the pecking rate.
Only after many sessions, or when they doubled the food drops, did the birds slow a little.
Even then, the drop was small.
How this fits with other research
Harper (1996) saw the same weak slow-down, but wrapped it in behavioral momentum theory.
Eugenia Gras et al. (2003) later showed bigger or longer NCR makes the slow-down stronger.
Pritchard et al. (1987) added a twist: even delayed contingent food kept rates higher than the free-food schedule, so contingency still matters.
Why it matters
If you use noncontingent reinforcement to reduce problem behavior, do not expect a quick or big drop. You may need to deliver it twice as often and wait many sessions. Keep the portions small and sessions short, or you might over-suppress the replacement skills you want to keep.
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02At a glance
03Original abstract
Following fixed-ratio baselines, the independent delivery of reinforcers was scheduled alone or concomitant with the fixed-ratio schedule for all subjects. Systematic manipulations of either the interreinforcement interval or the ratio size were also made during concomitant schedules. Response rates during the independent delivery of reinforcers did not decelerate until the subjects had been exposed for 50 or more sessions. Rates decelerated after a few sessions when the interreinforcement intervals were less than half of the original value and scheduled along with the ratio dependency. When both schedules were available, reductions in the ratio size resulted in slight deceleration of response rate when compared with the level of deceleration yielded by reductions in the independent reinforcement intervals.
Journal of the experimental analysis of behavior, 1970 · doi:10.1901/jeab.1970.14-301