Effects of reinforcer consumption and magnitude on response rates during noncontingent reinforcement.
Bigger or longer NCR deliveries suppress behavior more—keep magnitudes small and sessions brief to avoid over-suppression.
01Research in Context
What this study did
Eugenia Gras et al. (2003) tested how big and how long noncontingent food deliveries affect response rates. They ran sessions with adults who had developmental disabilities. The team varied the size of each free bite and the length of the session while tracking every lever press.
What they found
Larger bites and longer sessions both pushed response rates down, even after the time spent eating was subtracted. The suppression was not just from the mouth being full; the schedule itself quieted the behavior.
How this fits with other research
Gaily et al. (1998) saw the same dose effect five years earlier: bigger free snacks cut responding more. The new study adds that session length matters too, not just bite size.
Foltin (1997) looks like a contradiction. Longer chances to run as a reinforcer also cut rats’ lever presses. The twist: running is an activity reinforcer, not food. Activity satiates faster than hunger, so longer access depressed responding instead of boosting it.
Oliver et al. (2002) found little benefit from tripling or fifteen-fold jumps in reinforcer time when teaching communicative responses. Under differential reinforcement, magnitude barely mattered; under noncontingent reinforcement, it clearly suppresses.
Why it matters
If you use NCR to reduce problem behavior, keep the free reinforcer small and the session short. A big cookie or a long movie clip can over-suppress desirable responses too. Start with tiny tastes—one sip, one sticker—and end the free delivery quickly. You can always thin later once the behavior is stable.
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02At a glance
03Original abstract
Results of previous research on the effects of noncontingent reinforcement (NCR) have been inconsistent when magnitude of reinforcement was manipulated. We attempted to clarify the influence of NCR magnitude by including additional controls. In Study 1, we examined the effects of reinforcer consumption time by comparing the same magnitude of NCR when session time was and was not corrected to account for reinforcer consumption. Lower response rates were observed when session time was not corrected, indicating that reinforcer consumption can suppress response rates. In Study 2, we first selected varying reinforcer magnitudes (small, medium, and large) on the basis of corrected response rates observed during a contingent reinforcement condition and then compared the effects of these magnitudes during NCR. One participant exhibited lower response rates when large-magnitude reinforcers were delivered; the other ceased responding altogether even when small-magnitude reinforcers were delivered. We also compared the effects of the same NCR magnitude (medium) during 10-min and 30-min sessions. Lower response rates were observed during 30-min sessions, indicating that the number of reinforcers consumed across a session can have the same effect as the number consumed per reinforcer delivery. These findings indicate that, even when response rate is corrected to account for reinforcer consumption, larger magnitudes of NCR (defined on either a per-delivery or per-session basis) result in lower response rates than do smaller magnitudes.
Journal of applied behavior analysis, 2003 · doi:10.1901/jaba.2003.36-525