Positive conditioned suppression: an explanation in terms of multiple and concurrent schedules.
Free food can quietly weaken other behaviors, so monitor all skills when using non-contingent reinforcement.
01Research in Context
What this study did
Neef et al. (1978) tested rats pressing a lever for food. They added extra food that the rats did not have to work for. The food just dropped in at set times.
The team watched how this free food changed the rats' lever pressing. They tried different lengths of food delivery to see if time mattered.
What they found
The free food made the rats press the lever less. Longer food times caused bigger drops in pressing.
This drop is called positive conditioned suppression. The food acted like a mild punisher even though it was still food.
How this fits with other research
Constantino et al. (2003) later used the same idea with children who mouthed objects. Fixed-time snacks reduced the mouthing both during and after snack time. This shows the 1978 lab effect can help in real therapy.
Clopton (1972) saw no contrast effect with free food, only with extinction. Neef et al. (1978) now show the food itself can suppress behavior. The two papers fit because M looked at preference shifts, not raw response drops.
Harper (1996) found that smaller baseline reinforcers let free food cause bigger drops. This supports the 1978 claim that suppression depends on food timing and current reinforcer size.
Why it matters
If you run non-contingent reinforcement to reduce problem behavior, watch for accidental suppression of good skills too. The same free snacks that calm stereotypy can also weaken manding or academic work. Check data across behaviors and thin the NCR schedule once the target behavior drops.
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02At a glance
03Original abstract
Rats performed under a baseline variable-interval schedule of food presentation. A response-independent food schedule was then superimposed on the baseline schedule for different periods of time across different conditions. The response-independent schedule operated for the whole session in some conditions, intermittently for sixty second periods in some, and intermittently for ten-second periods in others. Under these latter two sets of conditions, the response-independent food schedule was stimulus correlated and alternated with the baseline schedule according to a multiple schedule. Response-independent food presentations always suppressed responding. The degree of suppression tended to increase the longer the period of response-independent food. Control conditions, in which the superimposed schedule was response-dependent, rather than response-independent, did not produce response suppression. The results fit an analysis of positive conditioned suppression phenomena in the context of multiple and concurrent schedule effects.
Journal of the experimental analysis of behavior, 1978 · doi:10.1901/jeab.1978.30-329