The interaction between stimulus and reinforcer control on remembering.
Keep the gap between prompt and response under three seconds; later delays are far less harmful.
01Research in Context
What this study did
The team tested how two kinds of delays hurt memory.
They used a matching task. Subjects first saw a sample. Then they waited. Finally they picked the matching picture.
The scientists made two gaps longer: (1) sample-to-choice and (2) choice-to-reinforcer. They counted correct picks.
What they found
Longer sample-to-choice gaps slashed accuracy the most.
Longer choice-to-reinforcer gaps hurt less.
When the sample got harder to see, reinforcer control faded faster.
How this fits with other research
Bacon-Prue et al. (1980) saw the same quick memory drop in pigeons after only 2-4 s. The new study shows the rule still holds for people and for two delay types.
Van Hemel (1973) proved that stimuli lose power when they stop predicting reward. Here, the later paper adds that this loss speeds up if the sample itself is hard to tell apart.
Haemmerlie (1983) used concurrent-chain schedules to map how reinforcer timing changes choice. Duker et al. (1991) use the same method but ask which delay matters more for remembering, not just choosing.
Why it matters
Shorten the time between instruction and response in your sessions. A three-second wait can wipe stimulus control. If you must add a delay, put it after the response, not before.
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02At a glance
03Original abstract
In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering.
Journal of the experimental analysis of behavior, 1991 · doi:10.1901/jeab.1991.56-51