A molecular analysis of multiple schedule interactions: negative contrast.
You can erase negative contrast by no longer reinforcing the long pauses that the richer schedule once allowed.
01Research in Context
What this study did
The team worked with pigeons in a lab.
They used two VI schedules that switched back and forth.
In one schedule they paid birds for long pauses.
Then they stopped paying for pauses and watched rates drop.
What they found
Birds showed negative contrast when the rich schedule returned.
Rates fell below the old baseline.
Removing pay for long pauses erased the dip.
Contrast vanished when long pauses no longer earned food.
How this fits with other research
Van Hemel (1973) first mapped moment-to-moment rates in contrast.
Davol et al. (1977) now shows you can turn that map into a dial.
Green et al. (1975) saw local surges before switches.
The new study says those surges can be trained away.
Szatmari (1992) later added that extra reinforcers move between parts.
Together the papers show contrast has both IRT and reinforcer paths.
Why it matters
If a client tanks on Task A after you thin Task B, check what responses you still reinforce on A. Stop paying for slow or off-task forms and the dip should fade.
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02At a glance
03Original abstract
The present experiments investigated the relationship between changes in the relative reinforced interresponse-time distributions and the occurrence of positive and negative contrast in multiple variable-interval-variable-interval and multiple variable-interval-extinction schedules of reinforcement. Experiment I demonstrated that changes in the interresponse-time distributions were consistently correlated with response-rate changes referred to as positive and negative contrast. Corresponding changes in the reinforced interresponse-time distributions suggested that negative contrast resulted as an inductive effect of selectively reinforcing long interresponse times in the altered component at the moment the baseline schedule was reintroduced. Experiment II demonstrated that the magnitude of the negative-contrast effect could be significantly decreased if the altered component schedule was modified in order to prevent the reinforcement of these interresponse times during the first few sessions of baseline recovery. The results supported a proposal that interresponse time-reinforcer relations may act as amplifiers or attenuators of negative contrast.
Journal of the experimental analysis of behavior, 1977 · doi:10.1901/jeab.1977.28-71