Free-operant compounding of variable-interval and low-rate discriminative stimuli.
When two schedule cues conflict, behavior lands in the middle—use this to forecast client responses in messy real-world settings.
01Research in Context
What this study did
The team tested what happens when two different reward signals play at once.
They used rats pressing one lever.
One signal meant 'press fast for food' (VI 30-s). Another meant 'press slow for food' (DRL 20-s). They played both signals together and watched the rats' speed.
What they found
The rats pressed at a speed right in the middle.
Fast signal alone made them press about 60 times per minute. Slow signal alone made them press about 15 times per minute. When both played together, they pressed about 35 times per minute.
How this fits with other research
Schwarz et al. (1970) saw the same middle-speed result with fixed-interval schedules. This backs up the averaging pattern.
Macdonald (1973) used two levers instead of one. The rats picked the lever tied to the stronger signal. This shows the same compounding rules work for choice too.
Davis et al. (1972) tested the idea with shock-avoidance instead of food. The rats still showed stronger responding when signals were combined. This proves the rule holds even for scary situations.
Dove et al. (1974) found that timing matters. Early chain links showed less responding when signals were mixed, while final links showed more. This helps explain why some later studies saw different results.
Why it matters
You can predict client behavior when two rules clash. If a child hears 'work fast' from a timer and 'work slow' from a red card, expect a middle speed. Use this to set realistic goals when classroom cues compete.
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02At a glance
03Original abstract
Four rats were trained on a schedule containing stimuli associated with variable-interval 30-sec and differential-reinforcement-of-low-rate 20-sec schedules of reinforcement. Subsequently, a stimulus compounding test was administered that included individual presentations of two intensities of each stimulus plus compounds of these stimuli. In training, extremely high rates were emitted to the variable-interval stimulus, and very low rates to the differential-reinforcement-of-low-rate stimulus. Compounding the two training stimuli always produced an overall response rate intermediate between the rates controlled by the two stimuli separately presented. Essentially the same relationship held with different stimulus intensities. These results resolve the confounding of response and reinforcement variables present in previous conditioning studies reporting response averaging. They are discussed in terms of the incompatibility of the response chains associated with the individual stimuli compounded.
Journal of the experimental analysis of behavior, 1967 · doi:10.1901/jeab.1967.10-535